diff --git a/ChangeLog b/ChangeLog
index b67c2ed..49c3acf 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -42,6 +42,13 @@
 API Changes
    * Add a new X.509 API call `mbedtls_x509_parse_der_nocopy()`.
      See the Features section for more information.
+   * Allow to opt in to the removal the API mbedtls_ssl_get_peer_cert()
+     for the benefit of saving RAM, by disabling the new compile-time
+     option MBEDTLS_SSL_KEEP_PEER_CERTIFICATE (enabled by default for
+     API stability). Disabling this option makes mbedtls_ssl_get_peer_cert()
+     always return NULL, and removes the peer_cert field from the
+     mbedtls_ssl_session structure which otherwise stores the peer's
+     certificate.
 
 Bugfix
    * Server's RSA certificate in certs.c was SHA-1 signed. In the default
diff --git a/include/mbedtls/check_config.h b/include/mbedtls/check_config.h
index 00fb9b3..67cb778 100644
--- a/include/mbedtls/check_config.h
+++ b/include/mbedtls/check_config.h
@@ -278,6 +278,14 @@
 #error "MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED defined, but not all prerequisites"
 #endif
 
+#if defined(MBEDTLS_KEY_EXCHANGE__WITH_CERT__ENABLED) &&        \
+    !defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE) &&              \
+    ( !defined(MBEDTLS_SHA256_C) &&                             \
+      !defined(MBEDTLS_SHA512_C) &&                             \
+      !defined(MBEDTLS_SHA1_C) )
+#error "MBEDTLS_SSL_KEEP_PEER_CERTIFICATE defined, but not all prerequesites"
+#endif
+
 #if defined(MBEDTLS_MEMORY_BUFFER_ALLOC_C) &&                          \
     ( !defined(MBEDTLS_PLATFORM_C) || !defined(MBEDTLS_PLATFORM_MEMORY) )
 #error "MBEDTLS_MEMORY_BUFFER_ALLOC_C defined, but not all prerequisites"
diff --git a/include/mbedtls/config.h b/include/mbedtls/config.h
index 9fc512e..e5d5933 100644
--- a/include/mbedtls/config.h
+++ b/include/mbedtls/config.h
@@ -1405,6 +1405,28 @@
 #define MBEDTLS_SSL_FALLBACK_SCSV
 
 /**
+ * \def MBEDTLS_SSL_KEEP_PEER_CERTIFICATE
+ *
+ * This option controls the availability of the API mbedtls_ssl_get_peer_cert()
+ * giving access to the peer's certificate after completion of the handshake.
+ *
+ * Unless you need mbedtls_ssl_peer_cert() in your application, it is
+ * recommended to disable this option for reduced RAM usage.
+ *
+ * \note If this option is disabled, mbedtls_ssl_get_peer_cert() is still
+ *       defined, but always returns \c NULL.
+ *
+ * \note This option has no influence on the protection against the
+ *       triple handshake attack. Even if it is disabled, Mbed TLS will
+ *       still ensure that certificates do not change during renegotiation,
+ *       for exaple by keeping a hash of the peer's certificate.
+ *
+ * Comment this macro to disable storing the peer's certificate
+ * after the handshake.
+ */
+#define MBEDTLS_SSL_KEEP_PEER_CERTIFICATE
+
+/**
  * \def MBEDTLS_SSL_HW_RECORD_ACCEL
  *
  * Enable hooking functions in SSL module for hardware acceleration of
diff --git a/include/mbedtls/ssl.h b/include/mbedtls/ssl.h
index 6e1bb3a..9a36009 100644
--- a/include/mbedtls/ssl.h
+++ b/include/mbedtls/ssl.h
@@ -812,6 +812,25 @@
 typedef void mbedtls_ssl_async_cancel_t( mbedtls_ssl_context *ssl );
 #endif /* MBEDTLS_SSL_ASYNC_PRIVATE */
 
+#if defined(MBEDTLS_KEY_EXCHANGE__WITH_CERT__ENABLED) &&        \
+    !defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
+#define MBEDTLS_SSL_PEER_CERT_DIGEST_MAX_LEN  48
+#if defined(MBEDTLS_SHA256_C)
+#define MBEDTLS_SSL_PEER_CERT_DIGEST_DFL_TYPE MBEDTLS_MD_SHA256
+#define MBEDTLS_SSL_PEER_CERT_DIGEST_DFL_LEN  32
+#elif defined(MBEDTLS_SHA512_C)
+#define MBEDTLS_SSL_PEER_CERT_DIGEST_DFL_TYPE MBEDTLS_MD_SHA384
+#define MBEDTLS_SSL_PEER_CERT_DIGEST_DFL_LEN  48
+#elif defined(MBEDTLS_SHA1_C)
+#define MBEDTLS_SSL_PEER_CERT_DIGEST_DFL_TYPE MBEDTLS_MD_SHA1
+#define MBEDTLS_SSL_PEER_CERT_DIGEST_DFL_LEN  20
+#else
+/* This is already checked in check_config.h, but be sure. */
+#error "Bad configuration - need SHA-1, SHA-256 or SHA-512 enabled to compute digest of peer CRT."
+#endif
+#endif /* MBEDTLS_KEY_EXCHANGE__WITH_CERT__ENABLED &&
+          !MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
+
 /*
  * This structure is used for storing current session data.
  *
@@ -835,7 +854,15 @@
     unsigned char master[48];   /*!< the master secret  */
 
 #if defined(MBEDTLS_X509_CRT_PARSE_C)
-    mbedtls_x509_crt *peer_cert;        /*!< peer X.509 cert chain */
+#if defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
+    mbedtls_x509_crt *peer_cert;       /*!< peer X.509 cert chain */
+#else /* MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
+    /*! The digest of the peer's end-CRT. This must be kept to detect CRT
+     *  changes during renegotiation, mitigating the triple handshake attack. */
+    unsigned char *peer_cert_digest;
+    size_t peer_cert_digest_len;
+    mbedtls_md_type_t peer_cert_digest_type;
+#endif /* !MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
 #endif /* MBEDTLS_X509_CRT_PARSE_C */
     uint32_t verify_result;          /*!<  verification result     */
 
@@ -3230,18 +3257,34 @@
 
 #if defined(MBEDTLS_X509_CRT_PARSE_C)
 /**
- * \brief          Return the peer certificate from the current connection
+ * \brief          Return the peer certificate from the current connection.
  *
- *                 Note: Can be NULL in case no certificate was sent during
- *                 the handshake. Different calls for the same connection can
- *                 return the same or different pointers for the same
- *                 certificate and even a different certificate altogether.
- *                 The peer cert CAN change in a single connection if
- *                 renegotiation is performed.
+ * \param  ssl     The SSL context to use. This must be initialized and setup.
  *
- * \param ssl      SSL context
+ * \return         The current peer certificate, if available.
+ *                 The returned certificate is owned by the SSL context and
+ *                 is valid only until the next call to the SSL API.
+ * \return         \c NULL if no peer certificate is available. This might
+ *                 be because the chosen ciphersuite doesn't use CRTs
+ *                 (PSK-based ciphersuites, for example), or because
+ *                 #MBEDTLS_SSL_KEEP_PEER_CERTIFICATE has been disabled,
+ *                 allowing the stack to free the peer's CRT to save memory.
  *
- * \return         the current peer certificate
+ * \note           For one-time inspection of the peer's certificate during
+ *                 the handshake, consider registering an X.509 CRT verification
+ *                 callback through mbedtls_ssl_conf_verify() instead of calling
+ *                 this function. Using mbedtls_ssl_conf_verify() also comes at
+ *                 the benefit of allowing you to influence the verification
+ *                 process, for example by masking expected and tolerated
+ *                 verification failures.
+ *
+ * \warning        You must not use the pointer returned by this function
+ *                 after any further call to the SSL API, including
+ *                 mbedtls_ssl_read() and mbedtls_ssl_write(); this is
+ *                 because the pointer might change during renegotiation,
+ *                 which happens transparently to the user.
+ *                 If you want to use the certificate across API calls,
+ *                 you must make a copy.
  */
 const mbedtls_x509_crt *mbedtls_ssl_get_peer_cert( const mbedtls_ssl_context *ssl );
 #endif /* MBEDTLS_X509_CRT_PARSE_C */
diff --git a/include/mbedtls/ssl_cache.h b/include/mbedtls/ssl_cache.h
index 52ba094..84254d3 100644
--- a/include/mbedtls/ssl_cache.h
+++ b/include/mbedtls/ssl_cache.h
@@ -70,7 +70,8 @@
     mbedtls_time_t timestamp;           /*!< entry timestamp    */
 #endif
     mbedtls_ssl_session session;        /*!< entry session      */
-#if defined(MBEDTLS_X509_CRT_PARSE_C)
+#if defined(MBEDTLS_X509_CRT_PARSE_C) && \
+    defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
     mbedtls_x509_buf peer_cert;         /*!< entry peer_cert    */
 #endif
     mbedtls_ssl_cache_entry *next;      /*!< chain pointer      */
diff --git a/include/mbedtls/ssl_ciphersuites.h b/include/mbedtls/ssl_ciphersuites.h
index 71053e5..7126783 100644
--- a/include/mbedtls/ssl_ciphersuites.h
+++ b/include/mbedtls/ssl_ciphersuites.h
@@ -486,6 +486,24 @@
     }
 }
 
+static inline int mbedtls_ssl_ciphersuite_uses_srv_cert( const mbedtls_ssl_ciphersuite_t *info )
+{
+    switch( info->key_exchange )
+    {
+        case MBEDTLS_KEY_EXCHANGE_RSA:
+        case MBEDTLS_KEY_EXCHANGE_RSA_PSK:
+        case MBEDTLS_KEY_EXCHANGE_DHE_RSA:
+        case MBEDTLS_KEY_EXCHANGE_ECDH_RSA:
+        case MBEDTLS_KEY_EXCHANGE_ECDHE_RSA:
+        case MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA:
+        case MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA:
+            return( 1 );
+
+        default:
+            return( 0 );
+    }
+}
+
 #if defined(MBEDTLS_KEY_EXCHANGE__SOME__DHE_ENABLED)
 static inline int mbedtls_ssl_ciphersuite_uses_dhe( const mbedtls_ssl_ciphersuite_t *info )
 {
diff --git a/include/mbedtls/ssl_internal.h b/include/mbedtls/ssl_internal.h
index 8089441..3eb37b8 100644
--- a/include/mbedtls/ssl_internal.h
+++ b/include/mbedtls/ssl_internal.h
@@ -396,8 +396,13 @@
         ssl_ecrs_cke_ecdh_calc_secret,  /*!< ClientKeyExchange: ECDH step 2 */
         ssl_ecrs_crt_vrfy_sign,         /*!< CertificateVerify: pk_sign()   */
     } ecrs_state;                       /*!< current (or last) operation    */
+    mbedtls_x509_crt *ecrs_peer_cert;   /*!< The peer's CRT chain.          */
     size_t ecrs_n;                      /*!< place for saving a length      */
 #endif
+#if defined(MBEDTLS_X509_CRT_PARSE_C) && \
+    !defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
+    mbedtls_pk_context peer_pubkey;     /*!< The public key from the peer.  */
+#endif /* MBEDTLS_X509_CRT_PARSE_C && !MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
 #if defined(MBEDTLS_SSL_PROTO_DTLS)
     unsigned int out_msg_seq;           /*!<  Outgoing handshake sequence number */
     unsigned int in_msg_seq;            /*!<  Incoming handshake sequence number */
@@ -989,6 +994,9 @@
 void mbedtls_ssl_dtls_replay_update( mbedtls_ssl_context *ssl );
 #endif
 
+int mbedtls_ssl_session_copy( mbedtls_ssl_session *dst,
+                              const mbedtls_ssl_session *src );
+
 /* constant-time buffer comparison */
 static inline int mbedtls_ssl_safer_memcmp( const void *a, const void *b, size_t n )
 {
diff --git a/include/mbedtls/x509_crt.h b/include/mbedtls/x509_crt.h
index dc3260b..09ba69f 100644
--- a/include/mbedtls/x509_crt.h
+++ b/include/mbedtls/x509_crt.h
@@ -70,6 +70,7 @@
     mbedtls_x509_time valid_from;       /**< Start time of certificate validity. */
     mbedtls_x509_time valid_to;         /**< End time of certificate validity. */
 
+    mbedtls_x509_buf pk_raw;
     mbedtls_pk_context pk;              /**< Container for the public key context. */
 
     mbedtls_x509_buf issuer_id;         /**< Optional X.509 v2/v3 issuer unique identifier. */
diff --git a/library/ssl_cache.c b/library/ssl_cache.c
index 47867f1..62a0a29 100644
--- a/library/ssl_cache.c
+++ b/library/ssl_cache.c
@@ -40,6 +40,7 @@
 #endif
 
 #include "mbedtls/ssl_cache.h"
+#include "mbedtls/ssl_internal.h"
 
 #include <string.h>
 
@@ -92,16 +93,24 @@
                     entry->session.id_len ) != 0 )
             continue;
 
-        memcpy( session->master, entry->session.master, 48 );
+        ret = mbedtls_ssl_session_copy( session, &entry->session );
+        if( ret != 0 )
+        {
+            ret = 1;
+            goto exit;
+        }
 
-        session->verify_result = entry->session.verify_result;
-
-#if defined(MBEDTLS_X509_CRT_PARSE_C)
+#if defined(MBEDTLS_X509_CRT_PARSE_C) && \
+    defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
         /*
          * Restore peer certificate (without rest of the original chain)
          */
         if( entry->peer_cert.p != NULL )
         {
+            /* `session->peer_cert` is NULL after the call to
+             * mbedtls_ssl_session_copy(), because cache entries
+             * have the `peer_cert` field set to NULL. */
+
             if( ( session->peer_cert = mbedtls_calloc( 1,
                                  sizeof(mbedtls_x509_crt) ) ) == NULL )
             {
@@ -119,7 +128,7 @@
                 goto exit;
             }
         }
-#endif /* MBEDTLS_X509_CRT_PARSE_C */
+#endif /* MBEDTLS_X509_CRT_PARSE_C && MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
 
         ret = 0;
         goto exit;
@@ -239,9 +248,8 @@
 #endif
     }
 
-    memcpy( &cur->session, session, sizeof( mbedtls_ssl_session ) );
-
-#if defined(MBEDTLS_X509_CRT_PARSE_C)
+#if defined(MBEDTLS_X509_CRT_PARSE_C) && \
+    defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
     /*
      * If we're reusing an entry, free its certificate first
      */
@@ -250,26 +258,43 @@
         mbedtls_free( cur->peer_cert.p );
         memset( &cur->peer_cert, 0, sizeof(mbedtls_x509_buf) );
     }
+#endif /* MBEDTLS_X509_CRT_PARSE_C && MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
 
-    /*
-     * Store peer certificate
-     */
-    if( session->peer_cert != NULL )
+    /* Copy the entire session; this temporarily makes a copy of the
+     * X.509 CRT structure even though we only want to store the raw CRT.
+     * This inefficiency will go away as soon as we implement on-demand
+     * parsing of CRTs, in which case there's no need for the `peer_cert`
+     * field anymore in the first place, and we're done after this call. */
+    ret = mbedtls_ssl_session_copy( &cur->session, session );
+    if( ret != 0 )
     {
-        cur->peer_cert.p = mbedtls_calloc( 1, session->peer_cert->raw.len );
+        ret = 1;
+        goto exit;
+    }
+
+#if defined(MBEDTLS_X509_CRT_PARSE_C) && \
+    defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
+    /* If present, free the X.509 structure and only store the raw CRT data. */
+    if( cur->session.peer_cert != NULL )
+    {
+        cur->peer_cert.p =
+            mbedtls_calloc( 1, cur->session.peer_cert->raw.len );
         if( cur->peer_cert.p == NULL )
         {
             ret = 1;
             goto exit;
         }
 
-        memcpy( cur->peer_cert.p, session->peer_cert->raw.p,
-                session->peer_cert->raw.len );
+        memcpy( cur->peer_cert.p,
+                cur->session.peer_cert->raw.p,
+                cur->session.peer_cert->raw.len );
         cur->peer_cert.len = session->peer_cert->raw.len;
 
+        mbedtls_x509_crt_free( cur->session.peer_cert );
+        mbedtls_free( cur->session.peer_cert );
         cur->session.peer_cert = NULL;
     }
-#endif /* MBEDTLS_X509_CRT_PARSE_C */
+#endif /* MBEDTLS_X509_CRT_PARSE_C && MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
 
     ret = 0;
 
@@ -311,9 +336,10 @@
 
         mbedtls_ssl_session_free( &prv->session );
 
-#if defined(MBEDTLS_X509_CRT_PARSE_C)
+#if defined(MBEDTLS_X509_CRT_PARSE_C) && \
+    defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
         mbedtls_free( prv->peer_cert.p );
-#endif /* MBEDTLS_X509_CRT_PARSE_C */
+#endif /* MBEDTLS_X509_CRT_PARSE_C && MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
 
         mbedtls_free( prv );
     }
diff --git a/library/ssl_cli.c b/library/ssl_cli.c
index cd9793e..e5185d4 100644
--- a/library/ssl_cli.c
+++ b/library/ssl_cli.c
@@ -2288,6 +2288,7 @@
     int ret;
     size_t len_bytes = ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_0 ? 0 : 2;
     unsigned char *p = ssl->handshake->premaster + pms_offset;
+    mbedtls_pk_context * peer_pk;
 
     if( offset + len_bytes > MBEDTLS_SSL_OUT_CONTENT_LEN )
     {
@@ -2313,23 +2314,28 @@
 
     ssl->handshake->pmslen = 48;
 
+#if !defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
+    peer_pk = &ssl->handshake->peer_pubkey;
+#else /* !MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
     if( ssl->session_negotiate->peer_cert == NULL )
     {
-        MBEDTLS_SSL_DEBUG_MSG( 2, ( "certificate required" ) );
-        return( MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE );
+        /* Should never happen */
+        MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
+        return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
     }
+    peer_pk = &ssl->session_negotiate->peer_cert->pk;
+#endif /* MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
 
     /*
      * Now write it out, encrypted
      */
-    if( ! mbedtls_pk_can_do( &ssl->session_negotiate->peer_cert->pk,
-                MBEDTLS_PK_RSA ) )
+    if( ! mbedtls_pk_can_do( peer_pk, MBEDTLS_PK_RSA ) )
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "certificate key type mismatch" ) );
         return( MBEDTLS_ERR_SSL_PK_TYPE_MISMATCH );
     }
 
-    if( ( ret = mbedtls_pk_encrypt( &ssl->session_negotiate->peer_cert->pk,
+    if( ( ret = mbedtls_pk_encrypt( peer_pk,
                             p, ssl->handshake->pmslen,
                             ssl->out_msg + offset + len_bytes, olen,
                             MBEDTLS_SSL_OUT_CONTENT_LEN - offset - len_bytes,
@@ -2349,6 +2355,10 @@
     }
 #endif
 
+#if !defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
+    /* We don't need the peer's public key anymore. Free it. */
+    mbedtls_pk_free( peer_pk );
+#endif /* !MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
     return( 0 );
 }
 #endif /* MBEDTLS_KEY_EXCHANGE_RSA_ENABLED ||
@@ -2424,21 +2434,27 @@
 {
     int ret;
     const mbedtls_ecp_keypair *peer_key;
+    mbedtls_pk_context * peer_pk;
 
+#if !defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
+    peer_pk = &ssl->handshake->peer_pubkey;
+#else /* !MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
     if( ssl->session_negotiate->peer_cert == NULL )
     {
-        MBEDTLS_SSL_DEBUG_MSG( 2, ( "certificate required" ) );
-        return( MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE );
+        /* Should never happen */
+        MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
+        return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
     }
+    peer_pk = &ssl->session_negotiate->peer_cert->pk;
+#endif /* MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
 
-    if( ! mbedtls_pk_can_do( &ssl->session_negotiate->peer_cert->pk,
-                     MBEDTLS_PK_ECKEY ) )
+    if( ! mbedtls_pk_can_do( peer_pk, MBEDTLS_PK_ECKEY ) )
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "server key not ECDH capable" ) );
         return( MBEDTLS_ERR_SSL_PK_TYPE_MISMATCH );
     }
 
-    peer_key = mbedtls_pk_ec( ssl->session_negotiate->peer_cert->pk );
+    peer_key = mbedtls_pk_ec( *peer_pk );
 
     if( ( ret = mbedtls_ecdh_get_params( &ssl->handshake->ecdh_ctx, peer_key,
                                  MBEDTLS_ECDH_THEIRS ) ) != 0 )
@@ -2453,6 +2469,13 @@
         return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE );
     }
 
+#if !defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
+    /* We don't need the peer's public key anymore. Free it,
+     * so that more RAM is available for upcoming expensive
+     * operations like ECDHE. */
+    mbedtls_pk_free( peer_pk );
+#endif /* !MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
+
     return( ret );
 }
 #endif /* MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED) ||
@@ -2645,6 +2668,8 @@
         size_t params_len = p - params;
         void *rs_ctx = NULL;
 
+        mbedtls_pk_context * peer_pk;
+
         /*
          * Handle the digitally-signed structure
          */
@@ -2747,18 +2772,22 @@
 
         MBEDTLS_SSL_DEBUG_BUF( 3, "parameters hash", hash, hashlen );
 
+#if !defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
+        peer_pk = &ssl->handshake->peer_pubkey;
+#else /* !MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
         if( ssl->session_negotiate->peer_cert == NULL )
         {
-            MBEDTLS_SSL_DEBUG_MSG( 2, ( "certificate required" ) );
-            mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
-                                            MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
-            return( MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE );
+            /* Should never happen */
+            MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
+            return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
         }
+        peer_pk = &ssl->session_negotiate->peer_cert->pk;
+#endif /* MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
 
         /*
          * Verify signature
          */
-        if( ! mbedtls_pk_can_do( &ssl->session_negotiate->peer_cert->pk, pk_alg ) )
+        if( !mbedtls_pk_can_do( peer_pk, pk_alg ) )
         {
             MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad server key exchange message" ) );
             mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
@@ -2771,8 +2800,7 @@
             rs_ctx = &ssl->handshake->ecrs_ctx.pk;
 #endif
 
-        if( ( ret = mbedtls_pk_verify_restartable(
-                        &ssl->session_negotiate->peer_cert->pk,
+        if( ( ret = mbedtls_pk_verify_restartable( peer_pk,
                         md_alg, hash, hashlen, p, sig_len, rs_ctx ) ) != 0 )
         {
 #if defined(MBEDTLS_SSL__ECP_RESTARTABLE)
@@ -2787,6 +2815,13 @@
 #endif
             return( ret );
         }
+
+#if !defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
+        /* We don't need the peer's public key anymore. Free it,
+         * so that more RAM is available for upcoming expensive
+         * operations like ECDHE. */
+        mbedtls_pk_free( peer_pk );
+#endif /* !MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
     }
 #endif /* MBEDTLS_KEY_EXCHANGE__WITH_SERVER_SIGNATURE__ENABLED */
 
@@ -3306,12 +3341,7 @@
     return( 0 );
 }
 
-#if !defined(MBEDTLS_KEY_EXCHANGE_RSA_ENABLED)       && \
-    !defined(MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED)   && \
-    !defined(MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED)  && \
-    !defined(MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED) && \
-    !defined(MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED)&& \
-    !defined(MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED)
+#if !defined(MBEDTLS_KEY_EXCHANGE__CERT_REQ_ALLOWED__ENABLED)
 static int ssl_write_certificate_verify( mbedtls_ssl_context *ssl )
 {
     const mbedtls_ssl_ciphersuite_t *ciphersuite_info =
@@ -3326,11 +3356,7 @@
         return( ret );
     }
 
-    if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_PSK ||
-        ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA_PSK ||
-        ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_PSK ||
-        ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_DHE_PSK ||
-        ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECJPAKE )
+    if( !mbedtls_ssl_ciphersuite_cert_req_allowed( ciphersuite_info ) )
     {
         MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip write certificate verify" ) );
         ssl->state++;
@@ -3340,7 +3366,7 @@
     MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
     return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
 }
-#else
+#else /* !MBEDTLS_KEY_EXCHANGE__CERT_REQ_ALLOWED__ENABLED */
 static int ssl_write_certificate_verify( mbedtls_ssl_context *ssl )
 {
     int ret = MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE;
@@ -3369,11 +3395,7 @@
         return( ret );
     }
 
-    if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_PSK ||
-        ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA_PSK ||
-        ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_PSK ||
-        ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_DHE_PSK ||
-        ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECJPAKE )
+    if( !mbedtls_ssl_ciphersuite_cert_req_allowed( ciphersuite_info ) )
     {
         MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip write certificate verify" ) );
         ssl->state++;
@@ -3514,12 +3536,7 @@
 
     return( ret );
 }
-#endif /* !MBEDTLS_KEY_EXCHANGE_RSA_ENABLED &&
-          !MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED &&
-          !MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED &&
-          !MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED &&
-          !MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED &&
-          !MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED */
+#endif /* MBEDTLS_KEY_EXCHANGE__CERT_REQ_ALLOWED__ENABLED */
 
 #if defined(MBEDTLS_SSL_SESSION_TICKETS)
 static int ssl_parse_new_session_ticket( mbedtls_ssl_context *ssl )
diff --git a/library/ssl_srv.c b/library/ssl_srv.c
index d40a21f..06fe3ee 100644
--- a/library/ssl_srv.c
+++ b/library/ssl_srv.c
@@ -2801,12 +2801,7 @@
     return( ret );
 }
 
-#if !defined(MBEDTLS_KEY_EXCHANGE_RSA_ENABLED)       && \
-    !defined(MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED)   && \
-    !defined(MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED)  && \
-    !defined(MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED) && \
-    !defined(MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED)&& \
-    !defined(MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED)
+#if !defined(MBEDTLS_KEY_EXCHANGE__CERT_REQ_ALLOWED__ENABLED)
 static int ssl_write_certificate_request( mbedtls_ssl_context *ssl )
 {
     const mbedtls_ssl_ciphersuite_t *ciphersuite_info =
@@ -2814,11 +2809,7 @@
 
     MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write certificate request" ) );
 
-    if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_PSK ||
-        ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA_PSK ||
-        ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_DHE_PSK ||
-        ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_PSK ||
-        ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECJPAKE )
+    if( !mbedtls_ssl_ciphersuite_cert_req_allowed( ciphersuite_info ) )
     {
         MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip write certificate request" ) );
         ssl->state++;
@@ -2828,7 +2819,7 @@
     MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
     return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
 }
-#else
+#else /* !MBEDTLS_KEY_EXCHANGE__CERT_REQ_ALLOWED__ENABLED */
 static int ssl_write_certificate_request( mbedtls_ssl_context *ssl )
 {
     int ret = MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE;
@@ -2852,11 +2843,7 @@
 #endif
         authmode = ssl->conf->authmode;
 
-    if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_PSK ||
-        ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA_PSK ||
-        ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_DHE_PSK ||
-        ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_PSK ||
-        ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECJPAKE ||
+    if( !mbedtls_ssl_ciphersuite_cert_req_allowed( ciphersuite_info ) ||
         authmode == MBEDTLS_SSL_VERIFY_NONE )
     {
         MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip write certificate request" ) );
@@ -2995,12 +2982,7 @@
 
     return( ret );
 }
-#endif /* !MBEDTLS_KEY_EXCHANGE_RSA_ENABLED &&
-          !MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED &&
-          !MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED &&
-          !MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED &&
-          !MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED &&
-          !MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED */
+#endif /* MBEDTLS_KEY_EXCHANGE__CERT_REQ_ALLOWED__ENABLED */
 
 #if defined(MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED) || \
     defined(MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED)
@@ -4147,12 +4129,7 @@
     return( 0 );
 }
 
-#if !defined(MBEDTLS_KEY_EXCHANGE_RSA_ENABLED)       && \
-    !defined(MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED)   && \
-    !defined(MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED)  && \
-    !defined(MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED) && \
-    !defined(MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED)&& \
-    !defined(MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED)
+#if !defined(MBEDTLS_KEY_EXCHANGE__CERT_REQ_ALLOWED__ENABLED)
 static int ssl_parse_certificate_verify( mbedtls_ssl_context *ssl )
 {
     const mbedtls_ssl_ciphersuite_t *ciphersuite_info =
@@ -4160,11 +4137,7 @@
 
     MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse certificate verify" ) );
 
-    if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_PSK ||
-        ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA_PSK ||
-        ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_PSK ||
-        ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_DHE_PSK ||
-        ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECJPAKE )
+    if( !mbedtls_ssl_ciphersuite_cert_req_allowed( ciphersuite_info ) )
     {
         MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip parse certificate verify" ) );
         ssl->state++;
@@ -4174,7 +4147,7 @@
     MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
     return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
 }
-#else
+#else /* !MBEDTLS_KEY_EXCHANGE__CERT_REQ_ALLOWED__ENABLED */
 static int ssl_parse_certificate_verify( mbedtls_ssl_context *ssl )
 {
     int ret = MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE;
@@ -4188,21 +4161,33 @@
     mbedtls_md_type_t md_alg;
     const mbedtls_ssl_ciphersuite_t *ciphersuite_info =
         ssl->handshake->ciphersuite_info;
+    mbedtls_pk_context * peer_pk;
 
     MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse certificate verify" ) );
 
-    if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_PSK ||
-        ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA_PSK ||
-        ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_PSK ||
-        ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_DHE_PSK ||
-        ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECJPAKE ||
-        ssl->session_negotiate->peer_cert == NULL )
+    if( !mbedtls_ssl_ciphersuite_cert_req_allowed( ciphersuite_info ) )
     {
         MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip parse certificate verify" ) );
         ssl->state++;
         return( 0 );
     }
 
+#if defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
+    if( ssl->session_negotiate->peer_cert == NULL )
+    {
+        MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip parse certificate verify" ) );
+        ssl->state++;
+        return( 0 );
+    }
+#else /* MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
+    if( ssl->session_negotiate->peer_cert_digest == NULL )
+    {
+        MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip parse certificate verify" ) );
+        ssl->state++;
+        return( 0 );
+    }
+#endif /* !MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
+
     /* Read the message without adding it to the checksum */
     ret = mbedtls_ssl_read_record( ssl, 0 /* no checksum update */ );
     if( 0 != ret )
@@ -4223,6 +4208,17 @@
 
     i = mbedtls_ssl_hs_hdr_len( ssl );
 
+#if !defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
+    peer_pk = &ssl->handshake->peer_pubkey;
+#else /* !MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
+    if( ssl->session_negotiate->peer_cert == NULL )
+    {
+        /* Should never happen */
+        return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
+    }
+    peer_pk = &ssl->session_negotiate->peer_cert->pk;
+#endif /* MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
+
     /*
      *  struct {
      *     SignatureAndHashAlgorithm algorithm; -- TLS 1.2 only
@@ -4237,8 +4233,7 @@
         hashlen = 36;
 
         /* For ECDSA, use SHA-1, not MD-5 + SHA-1 */
-        if( mbedtls_pk_can_do( &ssl->session_negotiate->peer_cert->pk,
-                        MBEDTLS_PK_ECDSA ) )
+        if( mbedtls_pk_can_do( peer_pk, MBEDTLS_PK_ECDSA ) )
         {
             hash_start += 16;
             hashlen -= 16;
@@ -4293,7 +4288,7 @@
         /*
          * Check the certificate's key type matches the signature alg
          */
-        if( ! mbedtls_pk_can_do( &ssl->session_negotiate->peer_cert->pk, pk_alg ) )
+        if( !mbedtls_pk_can_do( peer_pk, pk_alg ) )
         {
             MBEDTLS_SSL_DEBUG_MSG( 1, ( "sig_alg doesn't match cert key" ) );
             return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY );
@@ -4329,7 +4324,7 @@
         ssl->handshake->calc_verify( ssl, hash, &dummy_hlen );
     }
 
-    if( ( ret = mbedtls_pk_verify( &ssl->session_negotiate->peer_cert->pk,
+    if( ( ret = mbedtls_pk_verify( peer_pk,
                            md_alg, hash_start, hashlen,
                            ssl->in_msg + i, sig_len ) ) != 0 )
     {
@@ -4343,12 +4338,7 @@
 
     return( ret );
 }
-#endif /* !MBEDTLS_KEY_EXCHANGE_RSA_ENABLED &&
-          !MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED &&
-          !MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED &&
-          !MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED &&
-          !MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED &&
-          !MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED */
+#endif /* MBEDTLS_KEY_EXCHANGE__CERT_REQ_ALLOWED__ENABLED */
 
 #if defined(MBEDTLS_SSL_SESSION_TICKETS)
 static int ssl_write_new_session_ticket( mbedtls_ssl_context *ssl )
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index 096b6c8..84a9b3b 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -368,13 +368,15 @@
 }
 #endif /* MBEDTLS_SSL_MAX_FRAGMENT_LENGTH */
 
-#if defined(MBEDTLS_SSL_CLI_C)
-static int ssl_session_copy( mbedtls_ssl_session *dst, const mbedtls_ssl_session *src )
+int mbedtls_ssl_session_copy( mbedtls_ssl_session *dst,
+                              const mbedtls_ssl_session *src )
 {
     mbedtls_ssl_session_free( dst );
     memcpy( dst, src, sizeof( mbedtls_ssl_session ) );
 
 #if defined(MBEDTLS_X509_CRT_PARSE_C)
+
+#if defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
     if( src->peer_cert != NULL )
     {
         int ret;
@@ -393,6 +395,21 @@
             return( ret );
         }
     }
+#else /* MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
+    if( src->peer_cert_digest != NULL )
+    {
+        dst->peer_cert_digest =
+            mbedtls_calloc( 1, src->peer_cert_digest_len );
+        if( dst->peer_cert_digest == NULL )
+            return( MBEDTLS_ERR_SSL_ALLOC_FAILED );
+
+        memcpy( dst->peer_cert_digest, src->peer_cert_digest,
+                src->peer_cert_digest_len );
+        dst->peer_cert_digest_type = src->peer_cert_digest_type;
+        dst->peer_cert_digest_len = src->peer_cert_digest_len;
+    }
+#endif /* MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
+
 #endif /* MBEDTLS_X509_CRT_PARSE_C */
 
 #if defined(MBEDTLS_SSL_SESSION_TICKETS) && defined(MBEDTLS_SSL_CLI_C)
@@ -408,7 +425,6 @@
 
     return( 0 );
 }
-#endif /* MBEDTLS_SSL_CLI_C */
 
 #if defined(MBEDTLS_SSL_HW_RECORD_ACCEL)
 int (*mbedtls_ssl_hw_record_init)( mbedtls_ssl_context *ssl,
@@ -5973,16 +5989,33 @@
     return( 0 );
 }
 
+#if defined(MBEDTLS_X509_CRT_PARSE_C)
+static void ssl_clear_peer_cert( mbedtls_ssl_session *session )
+{
+#if defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
+    if( session->peer_cert != NULL )
+    {
+        mbedtls_x509_crt_free( session->peer_cert );
+        mbedtls_free( session->peer_cert );
+        session->peer_cert = NULL;
+    }
+#else /* MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
+    if( session->peer_cert_digest != NULL )
+    {
+        /* Zeroization is not necessary. */
+        mbedtls_free( session->peer_cert_digest );
+        session->peer_cert_digest      = NULL;
+        session->peer_cert_digest_type = MBEDTLS_MD_NONE;
+        session->peer_cert_digest_len  = 0;
+    }
+#endif /* !MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
+}
+#endif /* MBEDTLS_X509_CRT_PARSE_C */
+
 /*
  * Handshake functions
  */
-#if !defined(MBEDTLS_KEY_EXCHANGE_RSA_ENABLED)         && \
-    !defined(MBEDTLS_KEY_EXCHANGE_RSA_PSK_ENABLED)     && \
-    !defined(MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED)     && \
-    !defined(MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED)   && \
-    !defined(MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED) && \
-    !defined(MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED)    && \
-    !defined(MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED)
+#if !defined(MBEDTLS_KEY_EXCHANGE__WITH_CERT__ENABLED)
 /* No certificate support -> dummy functions */
 int mbedtls_ssl_write_certificate( mbedtls_ssl_context *ssl )
 {
@@ -5990,10 +6023,7 @@
 
     MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write certificate" ) );
 
-    if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_PSK ||
-        ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_DHE_PSK ||
-        ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_PSK ||
-        ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECJPAKE )
+    if( !mbedtls_ssl_ciphersuite_uses_srv_cert( ciphersuite_info ) )
     {
         MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip write certificate" ) );
         ssl->state++;
@@ -6010,10 +6040,7 @@
 
     MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse certificate" ) );
 
-    if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_PSK ||
-        ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_DHE_PSK ||
-        ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_PSK ||
-        ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECJPAKE )
+    if( !mbedtls_ssl_ciphersuite_uses_srv_cert( ciphersuite_info ) )
     {
         MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip parse certificate" ) );
         ssl->state++;
@@ -6024,7 +6051,7 @@
     return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
 }
 
-#else
+#else /* MBEDTLS_KEY_EXCHANGE__WITH_CERT__ENABLED */
 /* Some certificate support -> implement write and parse */
 
 int mbedtls_ssl_write_certificate( mbedtls_ssl_context *ssl )
@@ -6036,10 +6063,7 @@
 
     MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write certificate" ) );
 
-    if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_PSK ||
-        ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_DHE_PSK ||
-        ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_PSK ||
-        ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECJPAKE )
+    if( !mbedtls_ssl_ciphersuite_uses_srv_cert( ciphersuite_info ) )
     {
         MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip write certificate" ) );
         ssl->state++;
@@ -6144,6 +6168,8 @@
 }
 
 #if defined(MBEDTLS_SSL_RENEGOTIATION) && defined(MBEDTLS_SSL_CLI_C)
+
+#if defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
 static int ssl_check_peer_crt_unchanged( mbedtls_ssl_context *ssl,
                                          unsigned char *crt_buf,
                                          size_t crt_buf_len )
@@ -6158,65 +6184,51 @@
 
     return( memcmp( peer_crt->raw.p, crt_buf, crt_buf_len ) );
 }
+#else /* MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
+static int ssl_check_peer_crt_unchanged( mbedtls_ssl_context *ssl,
+                                         unsigned char *crt_buf,
+                                         size_t crt_buf_len )
+{
+    int ret;
+    unsigned char const * const peer_cert_digest =
+        ssl->session->peer_cert_digest;
+    mbedtls_md_type_t const peer_cert_digest_type =
+        ssl->session->peer_cert_digest_type;
+    mbedtls_md_info_t const * const digest_info =
+        mbedtls_md_info_from_type( peer_cert_digest_type );
+    unsigned char tmp_digest[MBEDTLS_SSL_PEER_CERT_DIGEST_MAX_LEN];
+    size_t digest_len;
+
+    if( peer_cert_digest == NULL || digest_info == NULL )
+        return( -1 );
+
+    digest_len = mbedtls_md_get_size( digest_info );
+    if( digest_len > MBEDTLS_SSL_PEER_CERT_DIGEST_MAX_LEN )
+        return( -1 );
+
+    ret = mbedtls_md( digest_info, crt_buf, crt_buf_len, tmp_digest );
+    if( ret != 0 )
+        return( -1 );
+
+    return( memcmp( tmp_digest, peer_cert_digest, digest_len ) );
+}
+#endif /* MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
 #endif /* MBEDTLS_SSL_RENEGOTIATION && MBEDTLS_SSL_CLI_C */
 
 /*
  * Once the certificate message is read, parse it into a cert chain and
  * perform basic checks, but leave actual verification to the caller
  */
-static int ssl_parse_certificate_chain( mbedtls_ssl_context *ssl )
+static int ssl_parse_certificate_chain( mbedtls_ssl_context *ssl,
+                                        mbedtls_x509_crt *chain )
 {
     int ret;
+#if defined(MBEDTLS_SSL_RENEGOTIATION) && defined(MBEDTLS_SSL_CLI_C)
+    int crt_cnt=0;
+#endif
     size_t i, n;
     uint8_t alert;
 
-#if defined(MBEDTLS_SSL_SRV_C)
-#if defined(MBEDTLS_SSL_PROTO_SSL3)
-    /*
-     * Check if the client sent an empty certificate
-     */
-    if( ssl->conf->endpoint  == MBEDTLS_SSL_IS_SERVER &&
-        ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_0 )
-    {
-        if( ssl->in_msglen  == 2                        &&
-            ssl->in_msgtype == MBEDTLS_SSL_MSG_ALERT            &&
-            ssl->in_msg[0]  == MBEDTLS_SSL_ALERT_LEVEL_WARNING  &&
-            ssl->in_msg[1]  == MBEDTLS_SSL_ALERT_MSG_NO_CERT )
-        {
-            MBEDTLS_SSL_DEBUG_MSG( 1, ( "SSLv3 client has no certificate" ) );
-
-            /* The client was asked for a certificate but didn't send
-               one. The client should know what's going on, so we
-               don't send an alert. */
-            ssl->session_negotiate->verify_result = MBEDTLS_X509_BADCERT_MISSING;
-            return( MBEDTLS_ERR_SSL_NO_CLIENT_CERTIFICATE );
-        }
-    }
-#endif /* MBEDTLS_SSL_PROTO_SSL3 */
-
-#if defined(MBEDTLS_SSL_PROTO_TLS1) || defined(MBEDTLS_SSL_PROTO_TLS1_1) || \
-    defined(MBEDTLS_SSL_PROTO_TLS1_2)
-    if( ssl->conf->endpoint  == MBEDTLS_SSL_IS_SERVER &&
-        ssl->minor_ver != MBEDTLS_SSL_MINOR_VERSION_0 )
-    {
-        if( ssl->in_hslen   == 3 + mbedtls_ssl_hs_hdr_len( ssl ) &&
-            ssl->in_msgtype == MBEDTLS_SSL_MSG_HANDSHAKE    &&
-            ssl->in_msg[0]  == MBEDTLS_SSL_HS_CERTIFICATE   &&
-            memcmp( ssl->in_msg + mbedtls_ssl_hs_hdr_len( ssl ), "\0\0\0", 3 ) == 0 )
-        {
-            MBEDTLS_SSL_DEBUG_MSG( 1, ( "TLSv1 client has no certificate" ) );
-
-            /* The client was asked for a certificate but didn't send
-               one. The client should know what's going on, so we
-               don't send an alert. */
-            ssl->session_negotiate->verify_result = MBEDTLS_X509_BADCERT_MISSING;
-            return( MBEDTLS_ERR_SSL_NO_CLIENT_CERTIFICATE );
-        }
-    }
-#endif /* MBEDTLS_SSL_PROTO_TLS1 || MBEDTLS_SSL_PROTO_TLS1_1 || \
-          MBEDTLS_SSL_PROTO_TLS1_2 */
-#endif /* MBEDTLS_SSL_SRV_C */
-
     if( ssl->in_msgtype != MBEDTLS_SSL_MSG_HANDSHAKE )
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate message" ) );
@@ -6253,14 +6265,6 @@
     /* Make &ssl->in_msg[i] point to the beginning of the CRT chain. */
     i += 3;
 
-    /* In case we tried to reuse a session but it failed */
-    if( ssl->session_negotiate->peer_cert != NULL )
-    {
-        mbedtls_x509_crt_free( ssl->session_negotiate->peer_cert );
-        mbedtls_free( ssl->session_negotiate->peer_cert );
-        ssl->session_negotiate->peer_cert = NULL;
-    }
-
     /* Iterate through and parse the CRTs in the provided chain. */
     while( i < ssl->in_hslen )
     {
@@ -6298,66 +6302,40 @@
         }
 
         /* Check if we're handling the first CRT in the chain. */
-        if( ssl->session_negotiate->peer_cert == NULL )
+#if defined(MBEDTLS_SSL_RENEGOTIATION) && defined(MBEDTLS_SSL_CLI_C)
+        if( crt_cnt++ == 0 &&
+            ssl->conf->endpoint == MBEDTLS_SSL_IS_CLIENT &&
+            ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_IN_PROGRESS )
         {
             /* During client-side renegotiation, check that the server's
              * end-CRTs hasn't changed compared to the initial handshake,
              * mitigating the triple handshake attack. On success, reuse
              * the original end-CRT instead of parsing it again. */
-#if defined(MBEDTLS_SSL_RENEGOTIATION) && defined(MBEDTLS_SSL_CLI_C)
-            if( ssl->conf->endpoint == MBEDTLS_SSL_IS_CLIENT &&
-                ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_IN_PROGRESS )
+            MBEDTLS_SSL_DEBUG_MSG( 3, ( "Check that peer CRT hasn't changed during renegotiation" ) );
+            if( ssl_check_peer_crt_unchanged( ssl,
+                                              &ssl->in_msg[i],
+                                              n ) != 0 )
             {
-                MBEDTLS_SSL_DEBUG_MSG( 3, ( "Check that peer CRT hasn't changed during renegotiation" ) );
-                if( ssl_check_peer_crt_unchanged( ssl,
-                                                  &ssl->in_msg[i],
-                                                  n ) != 0 )
-                {
-                    MBEDTLS_SSL_DEBUG_MSG( 1, ( "new server cert during renegotiation" ) );
-                    mbedtls_ssl_send_alert_message( ssl,
-                             MBEDTLS_SSL_ALERT_LEVEL_FATAL,
-                             MBEDTLS_SSL_ALERT_MSG_ACCESS_DENIED );
-                    return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE );
-                }
-
-                /* Move CRT chain structure to new session instance. */
-                ssl->session_negotiate->peer_cert = ssl->session->peer_cert;
-                ssl->session->peer_cert = NULL;
-
-                /* Delete all remaining CRTs from the original CRT chain. */
-                mbedtls_x509_crt_free(
-                    ssl->session_negotiate->peer_cert->next );
-                mbedtls_free( ssl->session_negotiate->peer_cert->next );
-                ssl->session_negotiate->peer_cert->next = NULL;
-
-                i += n;
-                continue;
+                MBEDTLS_SSL_DEBUG_MSG( 1, ( "new server cert during renegotiation" ) );
+                mbedtls_ssl_send_alert_message( ssl,
+                                                MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                                MBEDTLS_SSL_ALERT_MSG_ACCESS_DENIED );
+                return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE );
             }
+
+            /* Now we can safely free the original chain. */
+            ssl_clear_peer_cert( ssl->session );
+        }
 #endif /* MBEDTLS_SSL_RENEGOTIATION && MBEDTLS_SSL_CLI_C */
 
-            /* Outside of client-side renegotiation, create a fresh X.509 CRT
-             * instance to parse the end-CRT into. */
-
-            ssl->session_negotiate->peer_cert =
-                mbedtls_calloc( 1, sizeof( mbedtls_x509_crt ) );
-            if( ssl->session_negotiate->peer_cert == NULL )
-            {
-                MBEDTLS_SSL_DEBUG_MSG( 1, ( "alloc(%d bytes) failed",
-                                            sizeof( mbedtls_x509_crt ) ) );
-                mbedtls_ssl_send_alert_message( ssl,
-                               MBEDTLS_SSL_ALERT_LEVEL_FATAL,
-                               MBEDTLS_SSL_ALERT_MSG_INTERNAL_ERROR );
-                return( MBEDTLS_ERR_SSL_ALLOC_FAILED );
-            }
-
-            mbedtls_x509_crt_init( ssl->session_negotiate->peer_cert );
-
-            /* Intentional fall through */
-        }
-
         /* Parse the next certificate in the chain. */
-        ret = mbedtls_x509_crt_parse_der( ssl->session_negotiate->peer_cert,
-                                          ssl->in_msg + i, n );
+#if defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
+        ret = mbedtls_x509_crt_parse_der( chain, ssl->in_msg + i, n );
+#else
+        /* If we don't need to store the CRT chain permanently, parse
+         * it in-place from the input buffer instead of making a copy. */
+        ret = mbedtls_x509_crt_parse_der_nocopy( chain, ssl->in_msg + i, n );
+#endif /* MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
         switch( ret )
         {
             case 0: /*ok*/
@@ -6385,15 +6363,292 @@
         i += n;
     }
 
-    MBEDTLS_SSL_DEBUG_CRT( 3, "peer certificate", ssl->session_negotiate->peer_cert );
+    MBEDTLS_SSL_DEBUG_CRT( 3, "peer certificate", chain );
     return( 0 );
 }
 
-int mbedtls_ssl_parse_certificate( mbedtls_ssl_context *ssl )
+#if defined(MBEDTLS_SSL_SRV_C)
+static int ssl_srv_check_client_no_crt_notification( mbedtls_ssl_context *ssl )
+{
+    if( ssl->conf->endpoint == MBEDTLS_SSL_IS_CLIENT )
+        return( -1 );
+
+#if defined(MBEDTLS_SSL_PROTO_SSL3)
+    /*
+     * Check if the client sent an empty certificate
+     */
+    if( ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_0 )
+    {
+        if( ssl->in_msglen  == 2                        &&
+            ssl->in_msgtype == MBEDTLS_SSL_MSG_ALERT            &&
+            ssl->in_msg[0]  == MBEDTLS_SSL_ALERT_LEVEL_WARNING  &&
+            ssl->in_msg[1]  == MBEDTLS_SSL_ALERT_MSG_NO_CERT )
+        {
+            MBEDTLS_SSL_DEBUG_MSG( 1, ( "SSLv3 client has no certificate" ) );
+            return( 0 );
+        }
+
+        return( -1 );
+    }
+#endif /* MBEDTLS_SSL_PROTO_SSL3 */
+
+#if defined(MBEDTLS_SSL_PROTO_TLS1) || defined(MBEDTLS_SSL_PROTO_TLS1_1) || \
+    defined(MBEDTLS_SSL_PROTO_TLS1_2)
+    if( ssl->in_hslen   == 3 + mbedtls_ssl_hs_hdr_len( ssl ) &&
+        ssl->in_msgtype == MBEDTLS_SSL_MSG_HANDSHAKE    &&
+        ssl->in_msg[0]  == MBEDTLS_SSL_HS_CERTIFICATE   &&
+        memcmp( ssl->in_msg + mbedtls_ssl_hs_hdr_len( ssl ), "\0\0\0", 3 ) == 0 )
+    {
+        MBEDTLS_SSL_DEBUG_MSG( 1, ( "TLSv1 client has no certificate" ) );
+        return( 0 );
+    }
+
+#endif /* MBEDTLS_SSL_PROTO_TLS1 || MBEDTLS_SSL_PROTO_TLS1_1 || \
+          MBEDTLS_SSL_PROTO_TLS1_2 */
+
+    return( -1 );
+}
+#endif /* MBEDTLS_SSL_SRV_C */
+
+/* Check if a certificate message is expected.
+ * Return either
+ * - SSL_CERTIFICATE_EXPECTED, or
+ * - SSL_CERTIFICATE_SKIP
+ * indicating whether a Certificate message is expected or not.
+ */
+#define SSL_CERTIFICATE_EXPECTED 0
+#define SSL_CERTIFICATE_SKIP     1
+static int ssl_parse_certificate_coordinate( mbedtls_ssl_context *ssl,
+                                             int authmode )
+{
+    const mbedtls_ssl_ciphersuite_t *ciphersuite_info =
+        ssl->handshake->ciphersuite_info;
+
+    if( !mbedtls_ssl_ciphersuite_uses_srv_cert( ciphersuite_info ) )
+        return( SSL_CERTIFICATE_SKIP );
+
+#if defined(MBEDTLS_SSL_SRV_C)
+    if( ssl->conf->endpoint == MBEDTLS_SSL_IS_SERVER )
+    {
+        if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA_PSK )
+            return( SSL_CERTIFICATE_SKIP );
+
+        if( authmode == MBEDTLS_SSL_VERIFY_NONE )
+        {
+            ssl->session_negotiate->verify_result =
+                MBEDTLS_X509_BADCERT_SKIP_VERIFY;
+            return( SSL_CERTIFICATE_SKIP );
+        }
+    }
+#else
+    ((void) authmode);
+#endif /* MBEDTLS_SSL_SRV_C */
+
+    return( SSL_CERTIFICATE_EXPECTED );
+}
+
+static int ssl_parse_certificate_verify( mbedtls_ssl_context *ssl,
+                                         int authmode,
+                                         mbedtls_x509_crt *chain,
+                                         void *rs_ctx )
+{
+    int ret = 0;
+    const mbedtls_ssl_ciphersuite_t *ciphersuite_info =
+        ssl->handshake->ciphersuite_info;
+    mbedtls_x509_crt *ca_chain;
+    mbedtls_x509_crl *ca_crl;
+
+    if( authmode == MBEDTLS_SSL_VERIFY_NONE )
+        return( 0 );
+
+#if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
+    if( ssl->handshake->sni_ca_chain != NULL )
+    {
+        ca_chain = ssl->handshake->sni_ca_chain;
+        ca_crl   = ssl->handshake->sni_ca_crl;
+    }
+    else
+#endif
+    {
+        ca_chain = ssl->conf->ca_chain;
+        ca_crl   = ssl->conf->ca_crl;
+    }
+
+    /*
+     * Main check: verify certificate
+     */
+    ret = mbedtls_x509_crt_verify_restartable(
+        chain,
+        ca_chain, ca_crl,
+        ssl->conf->cert_profile,
+        ssl->hostname,
+        &ssl->session_negotiate->verify_result,
+        ssl->conf->f_vrfy, ssl->conf->p_vrfy, rs_ctx );
+
+    if( ret != 0 )
+    {
+        MBEDTLS_SSL_DEBUG_RET( 1, "x509_verify_cert", ret );
+    }
+
+#if defined(MBEDTLS_SSL__ECP_RESTARTABLE)
+    if( ret == MBEDTLS_ERR_ECP_IN_PROGRESS )
+        return( MBEDTLS_ERR_SSL_CRYPTO_IN_PROGRESS );
+#endif
+
+    /*
+     * Secondary checks: always done, but change 'ret' only if it was 0
+     */
+
+#if defined(MBEDTLS_ECP_C)
+    {
+        const mbedtls_pk_context *pk = &chain->pk;
+
+        /* If certificate uses an EC key, make sure the curve is OK */
+        if( mbedtls_pk_can_do( pk, MBEDTLS_PK_ECKEY ) &&
+            mbedtls_ssl_check_curve( ssl, mbedtls_pk_ec( *pk )->grp.id ) != 0 )
+        {
+            ssl->session_negotiate->verify_result |= MBEDTLS_X509_BADCERT_BAD_KEY;
+
+            MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate (EC key curve)" ) );
+            if( ret == 0 )
+                ret = MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE;
+        }
+    }
+#endif /* MBEDTLS_ECP_C */
+
+    if( mbedtls_ssl_check_cert_usage( chain,
+                                      ciphersuite_info,
+                                      ! ssl->conf->endpoint,
+                                      &ssl->session_negotiate->verify_result ) != 0 )
+    {
+        MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate (usage extensions)" ) );
+        if( ret == 0 )
+            ret = MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE;
+    }
+
+    /* mbedtls_x509_crt_verify_with_profile is supposed to report a
+     * verification failure through MBEDTLS_ERR_X509_CERT_VERIFY_FAILED,
+     * with details encoded in the verification flags. All other kinds
+     * of error codes, including those from the user provided f_vrfy
+     * functions, are treated as fatal and lead to a failure of
+     * ssl_parse_certificate even if verification was optional. */
+    if( authmode == MBEDTLS_SSL_VERIFY_OPTIONAL &&
+        ( ret == MBEDTLS_ERR_X509_CERT_VERIFY_FAILED ||
+          ret == MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE ) )
+    {
+        ret = 0;
+    }
+
+    if( ca_chain == NULL && authmode == MBEDTLS_SSL_VERIFY_REQUIRED )
+    {
+        MBEDTLS_SSL_DEBUG_MSG( 1, ( "got no CA chain" ) );
+        ret = MBEDTLS_ERR_SSL_CA_CHAIN_REQUIRED;
+    }
+
+    if( ret != 0 )
+    {
+        uint8_t alert;
+
+        /* The certificate may have been rejected for several reasons.
+           Pick one and send the corresponding alert. Which alert to send
+           may be a subject of debate in some cases. */
+        if( ssl->session_negotiate->verify_result & MBEDTLS_X509_BADCERT_OTHER )
+            alert = MBEDTLS_SSL_ALERT_MSG_ACCESS_DENIED;
+        else if( ssl->session_negotiate->verify_result & MBEDTLS_X509_BADCERT_CN_MISMATCH )
+            alert = MBEDTLS_SSL_ALERT_MSG_BAD_CERT;
+        else if( ssl->session_negotiate->verify_result & MBEDTLS_X509_BADCERT_KEY_USAGE )
+            alert = MBEDTLS_SSL_ALERT_MSG_UNSUPPORTED_CERT;
+        else if( ssl->session_negotiate->verify_result & MBEDTLS_X509_BADCERT_EXT_KEY_USAGE )
+            alert = MBEDTLS_SSL_ALERT_MSG_UNSUPPORTED_CERT;
+        else if( ssl->session_negotiate->verify_result & MBEDTLS_X509_BADCERT_NS_CERT_TYPE )
+            alert = MBEDTLS_SSL_ALERT_MSG_UNSUPPORTED_CERT;
+        else if( ssl->session_negotiate->verify_result & MBEDTLS_X509_BADCERT_BAD_PK )
+            alert = MBEDTLS_SSL_ALERT_MSG_UNSUPPORTED_CERT;
+        else if( ssl->session_negotiate->verify_result & MBEDTLS_X509_BADCERT_BAD_KEY )
+            alert = MBEDTLS_SSL_ALERT_MSG_UNSUPPORTED_CERT;
+        else if( ssl->session_negotiate->verify_result & MBEDTLS_X509_BADCERT_EXPIRED )
+            alert = MBEDTLS_SSL_ALERT_MSG_CERT_EXPIRED;
+        else if( ssl->session_negotiate->verify_result & MBEDTLS_X509_BADCERT_REVOKED )
+            alert = MBEDTLS_SSL_ALERT_MSG_CERT_REVOKED;
+        else if( ssl->session_negotiate->verify_result & MBEDTLS_X509_BADCERT_NOT_TRUSTED )
+            alert = MBEDTLS_SSL_ALERT_MSG_UNKNOWN_CA;
+        else
+            alert = MBEDTLS_SSL_ALERT_MSG_CERT_UNKNOWN;
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        alert );
+    }
+
+#if defined(MBEDTLS_DEBUG_C)
+    if( ssl->session_negotiate->verify_result != 0 )
+    {
+        MBEDTLS_SSL_DEBUG_MSG( 3, ( "! Certificate verification flags %x",
+                                    ssl->session_negotiate->verify_result ) );
+    }
+    else
+    {
+        MBEDTLS_SSL_DEBUG_MSG( 3, ( "Certificate verification flags clear" ) );
+    }
+#endif /* MBEDTLS_DEBUG_C */
+
+    return( ret );
+}
+
+#if !defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
+static int ssl_remember_peer_crt_digest( mbedtls_ssl_context *ssl,
+                                         unsigned char *start, size_t len )
 {
     int ret;
-    const mbedtls_ssl_ciphersuite_t * const ciphersuite_info =
-          ssl->handshake->ciphersuite_info;
+    /* Remember digest of the peer's end-CRT. */
+    ssl->session_negotiate->peer_cert_digest =
+        mbedtls_calloc( 1, MBEDTLS_SSL_PEER_CERT_DIGEST_DFL_LEN );
+    if( ssl->session_negotiate->peer_cert_digest == NULL )
+    {
+        MBEDTLS_SSL_DEBUG_MSG( 1, ( "alloc(%d bytes) failed",
+                                    sizeof( MBEDTLS_SSL_PEER_CERT_DIGEST_DFL_LEN ) ) );
+        mbedtls_ssl_send_alert_message( ssl,
+                                        MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_INTERNAL_ERROR );
+
+        return( MBEDTLS_ERR_SSL_ALLOC_FAILED );
+    }
+
+    ret = mbedtls_md( mbedtls_md_info_from_type(
+                          MBEDTLS_SSL_PEER_CERT_DIGEST_DFL_TYPE ),
+                      start, len,
+                      ssl->session_negotiate->peer_cert_digest );
+
+    ssl->session_negotiate->peer_cert_digest_type =
+        MBEDTLS_SSL_PEER_CERT_DIGEST_DFL_TYPE;
+    ssl->session_negotiate->peer_cert_digest_len =
+        MBEDTLS_SSL_PEER_CERT_DIGEST_DFL_LEN;
+
+    return( ret );
+}
+
+static int ssl_remember_peer_pubkey( mbedtls_ssl_context *ssl,
+                                     unsigned char *start, size_t len )
+{
+    unsigned char *end = start + len;
+    int ret;
+
+    /* Make a copy of the peer's raw public key. */
+    mbedtls_pk_init( &ssl->handshake->peer_pubkey );
+    ret = mbedtls_pk_parse_subpubkey( &start, end,
+                                      &ssl->handshake->peer_pubkey );
+    if( ret != 0 )
+    {
+        /* We should have parsed the public key before. */
+        return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
+    }
+
+    return( 0 );
+}
+#endif /* !MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
+
+int mbedtls_ssl_parse_certificate( mbedtls_ssl_context *ssl )
+{
+    int ret = 0;
+    int crt_expected;
 #if defined(MBEDTLS_SSL_SRV_C) && defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
     const int authmode = ssl->handshake->sni_authmode != MBEDTLS_SSL_VERIFY_UNSET
                        ? ssl->handshake->sni_authmode
@@ -6402,43 +6657,23 @@
     const int authmode = ssl->conf->authmode;
 #endif
     void *rs_ctx = NULL;
+    mbedtls_x509_crt *chain = NULL;
 
     MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse certificate" ) );
 
-    if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_PSK ||
-        ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_DHE_PSK ||
-        ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_PSK ||
-        ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECJPAKE )
+    crt_expected = ssl_parse_certificate_coordinate( ssl, authmode );
+    if( crt_expected == SSL_CERTIFICATE_SKIP )
     {
         MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip parse certificate" ) );
-        ssl->state++;
-        return( 0 );
+        goto exit;
     }
 
-#if defined(MBEDTLS_SSL_SRV_C)
-    if( ssl->conf->endpoint == MBEDTLS_SSL_IS_SERVER &&
-        ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA_PSK )
-    {
-        MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip parse certificate" ) );
-        ssl->state++;
-        return( 0 );
-    }
-
-    if( ssl->conf->endpoint == MBEDTLS_SSL_IS_SERVER &&
-        authmode == MBEDTLS_SSL_VERIFY_NONE )
-    {
-        ssl->session_negotiate->verify_result = MBEDTLS_X509_BADCERT_SKIP_VERIFY;
-        MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip parse certificate" ) );
-
-        ssl->state++;
-        return( 0 );
-    }
-#endif
-
 #if defined(MBEDTLS_SSL__ECP_RESTARTABLE)
     if( ssl->handshake->ecrs_enabled &&
         ssl->handshake->ecrs_state == ssl_ecrs_crt_verify )
     {
+        chain = ssl->handshake->ecrs_peer_cert;
+        ssl->handshake->ecrs_peer_cert = NULL;
         goto crt_verify;
     }
 #endif
@@ -6448,22 +6683,44 @@
         /* mbedtls_ssl_read_record may have sent an alert already. We
            let it decide whether to alert. */
         MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_read_record", ret );
-        return( ret );
+        goto exit;
     }
 
-    if( ( ret = ssl_parse_certificate_chain( ssl ) ) != 0 )
-    {
 #if defined(MBEDTLS_SSL_SRV_C)
-        if( ret == MBEDTLS_ERR_SSL_NO_CLIENT_CERTIFICATE &&
-            authmode == MBEDTLS_SSL_VERIFY_OPTIONAL )
-        {
-            ret = 0;
-        }
-#endif
+    if( ssl_srv_check_client_no_crt_notification( ssl ) == 0 )
+    {
+        ssl->session_negotiate->verify_result = MBEDTLS_X509_BADCERT_MISSING;
 
-        ssl->state++;
-        return( ret );
+        if( authmode == MBEDTLS_SSL_VERIFY_OPTIONAL )
+            ret = 0;
+        else
+            ret = MBEDTLS_ERR_SSL_NO_CLIENT_CERTIFICATE;
+
+        goto exit;
     }
+#endif /* MBEDTLS_SSL_SRV_C */
+
+    /* Clear existing peer CRT structure in case we tried to
+     * reuse a session but it failed, and allocate a new one. */
+    ssl_clear_peer_cert( ssl->session_negotiate );
+
+    chain = mbedtls_calloc( 1, sizeof( mbedtls_x509_crt ) );
+    if( chain == NULL )
+    {
+        MBEDTLS_SSL_DEBUG_MSG( 1, ( "alloc(%d bytes) failed",
+                                    sizeof( mbedtls_x509_crt ) ) );
+        mbedtls_ssl_send_alert_message( ssl,
+                                        MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_INTERNAL_ERROR );
+
+        ret = MBEDTLS_ERR_SSL_ALLOC_FAILED;
+        goto exit;
+    }
+    mbedtls_x509_crt_init( chain );
+
+    ret = ssl_parse_certificate_chain( ssl, chain );
+    if( ret != 0 )
+        goto exit;
 
 #if defined(MBEDTLS_SSL__ECP_RESTARTABLE)
     if( ssl->handshake->ecrs_enabled)
@@ -6474,154 +6731,71 @@
         rs_ctx = &ssl->handshake->ecrs_ctx;
 #endif
 
-    if( authmode != MBEDTLS_SSL_VERIFY_NONE )
+    ret = ssl_parse_certificate_verify( ssl, authmode,
+                                        chain, rs_ctx );
+    if( ret != 0 )
+        goto exit;
+
+#if !defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
     {
-        mbedtls_x509_crt *ca_chain;
-        mbedtls_x509_crl *ca_crl;
+        unsigned char *crt_start, *pk_start;
+        size_t crt_len, pk_len;
 
-#if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
-        if( ssl->handshake->sni_ca_chain != NULL )
-        {
-            ca_chain = ssl->handshake->sni_ca_chain;
-            ca_crl   = ssl->handshake->sni_ca_crl;
-        }
-        else
-#endif
-        {
-            ca_chain = ssl->conf->ca_chain;
-            ca_crl   = ssl->conf->ca_crl;
-        }
+        /* We parse the CRT chain without copying, so
+         * these pointers point into the input buffer,
+         * and are hence still valid after freeing the
+         * CRT chain. */
 
-        /*
-         * Main check: verify certificate
-         */
-        ret = mbedtls_x509_crt_verify_restartable(
-                                ssl->session_negotiate->peer_cert,
-                                ca_chain, ca_crl,
-                                ssl->conf->cert_profile,
-                                ssl->hostname,
-                               &ssl->session_negotiate->verify_result,
-                                ssl->conf->f_vrfy, ssl->conf->p_vrfy, rs_ctx );
+        crt_start = chain->raw.p;
+        crt_len   = chain->raw.len;
 
+        pk_start = chain->pk_raw.p;
+        pk_len   = chain->pk_raw.len;
+
+        /* Free the CRT structures before computing
+         * digest and copying the peer's public key. */
+        mbedtls_x509_crt_free( chain );
+        mbedtls_free( chain );
+        chain = NULL;
+
+        ret = ssl_remember_peer_crt_digest( ssl, crt_start, crt_len );
         if( ret != 0 )
-        {
-            MBEDTLS_SSL_DEBUG_RET( 1, "x509_verify_cert", ret );
-        }
+            goto exit;
 
-#if defined(MBEDTLS_SSL__ECP_RESTARTABLE)
-        if( ret == MBEDTLS_ERR_ECP_IN_PROGRESS )
-            return( MBEDTLS_ERR_SSL_CRYPTO_IN_PROGRESS );
-#endif
-
-        /*
-         * Secondary checks: always done, but change 'ret' only if it was 0
-         */
-
-#if defined(MBEDTLS_ECP_C)
-        {
-            const mbedtls_pk_context *pk = &ssl->session_negotiate->peer_cert->pk;
-
-            /* If certificate uses an EC key, make sure the curve is OK */
-            if( mbedtls_pk_can_do( pk, MBEDTLS_PK_ECKEY ) &&
-                mbedtls_ssl_check_curve( ssl, mbedtls_pk_ec( *pk )->grp.id ) != 0 )
-            {
-                ssl->session_negotiate->verify_result |= MBEDTLS_X509_BADCERT_BAD_KEY;
-
-                MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate (EC key curve)" ) );
-                if( ret == 0 )
-                    ret = MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE;
-            }
-        }
-#endif /* MBEDTLS_ECP_C */
-
-        if( mbedtls_ssl_check_cert_usage( ssl->session_negotiate->peer_cert,
-                                 ciphersuite_info,
-                                 ! ssl->conf->endpoint,
-                                 &ssl->session_negotiate->verify_result ) != 0 )
-        {
-            MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate (usage extensions)" ) );
-            if( ret == 0 )
-                ret = MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE;
-        }
-
-        /* mbedtls_x509_crt_verify_with_profile is supposed to report a
-         * verification failure through MBEDTLS_ERR_X509_CERT_VERIFY_FAILED,
-         * with details encoded in the verification flags. All other kinds
-         * of error codes, including those from the user provided f_vrfy
-         * functions, are treated as fatal and lead to a failure of
-         * ssl_parse_certificate even if verification was optional. */
-        if( authmode == MBEDTLS_SSL_VERIFY_OPTIONAL &&
-            ( ret == MBEDTLS_ERR_X509_CERT_VERIFY_FAILED ||
-              ret == MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE ) )
-        {
-            ret = 0;
-        }
-
-        if( ca_chain == NULL && authmode == MBEDTLS_SSL_VERIFY_REQUIRED )
-        {
-            MBEDTLS_SSL_DEBUG_MSG( 1, ( "got no CA chain" ) );
-            ret = MBEDTLS_ERR_SSL_CA_CHAIN_REQUIRED;
-        }
-
+        ret = ssl_remember_peer_pubkey( ssl, pk_start, pk_len );
         if( ret != 0 )
-        {
-            uint8_t alert;
-
-            /* The certificate may have been rejected for several reasons.
-               Pick one and send the corresponding alert. Which alert to send
-               may be a subject of debate in some cases. */
-            if( ssl->session_negotiate->verify_result & MBEDTLS_X509_BADCERT_OTHER )
-                alert = MBEDTLS_SSL_ALERT_MSG_ACCESS_DENIED;
-            else if( ssl->session_negotiate->verify_result & MBEDTLS_X509_BADCERT_CN_MISMATCH )
-                alert = MBEDTLS_SSL_ALERT_MSG_BAD_CERT;
-            else if( ssl->session_negotiate->verify_result & MBEDTLS_X509_BADCERT_KEY_USAGE )
-                alert = MBEDTLS_SSL_ALERT_MSG_UNSUPPORTED_CERT;
-            else if( ssl->session_negotiate->verify_result & MBEDTLS_X509_BADCERT_EXT_KEY_USAGE )
-                alert = MBEDTLS_SSL_ALERT_MSG_UNSUPPORTED_CERT;
-            else if( ssl->session_negotiate->verify_result & MBEDTLS_X509_BADCERT_NS_CERT_TYPE )
-                alert = MBEDTLS_SSL_ALERT_MSG_UNSUPPORTED_CERT;
-            else if( ssl->session_negotiate->verify_result & MBEDTLS_X509_BADCERT_BAD_PK )
-                alert = MBEDTLS_SSL_ALERT_MSG_UNSUPPORTED_CERT;
-            else if( ssl->session_negotiate->verify_result & MBEDTLS_X509_BADCERT_BAD_KEY )
-                alert = MBEDTLS_SSL_ALERT_MSG_UNSUPPORTED_CERT;
-            else if( ssl->session_negotiate->verify_result & MBEDTLS_X509_BADCERT_EXPIRED )
-                alert = MBEDTLS_SSL_ALERT_MSG_CERT_EXPIRED;
-            else if( ssl->session_negotiate->verify_result & MBEDTLS_X509_BADCERT_REVOKED )
-                alert = MBEDTLS_SSL_ALERT_MSG_CERT_REVOKED;
-            else if( ssl->session_negotiate->verify_result & MBEDTLS_X509_BADCERT_NOT_TRUSTED )
-                alert = MBEDTLS_SSL_ALERT_MSG_UNKNOWN_CA;
-            else
-                alert = MBEDTLS_SSL_ALERT_MSG_CERT_UNKNOWN;
-            mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
-                                            alert );
-        }
-
-#if defined(MBEDTLS_DEBUG_C)
-        if( ssl->session_negotiate->verify_result != 0 )
-        {
-            MBEDTLS_SSL_DEBUG_MSG( 3, ( "! Certificate verification flags %x",
-                                        ssl->session_negotiate->verify_result ) );
-        }
-        else
-        {
-            MBEDTLS_SSL_DEBUG_MSG( 3, ( "Certificate verification flags clear" ) );
-        }
-#endif /* MBEDTLS_DEBUG_C */
+            goto exit;
     }
-
-    ssl->state++;
+#else /* !MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
+    /* Pass ownership to session structure. */
+    ssl->session_negotiate->peer_cert = chain;
+    chain = NULL;
+#endif /* MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
 
     MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= parse certificate" ) );
 
+exit:
+
+    if( ret == 0 )
+        ssl->state++;
+
+#if defined(MBEDTLS_SSL__ECP_RESTARTABLE)
+    if( ret == MBEDTLS_ERR_SSL_CRYPTO_IN_PROGRESS )
+    {
+        ssl->handshake->ecrs_peer_cert = chain;
+        chain = NULL;
+    }
+#endif
+
+    if( chain != NULL )
+    {
+        mbedtls_x509_crt_free( chain );
+        mbedtls_free( chain );
+    }
+
     return( ret );
 }
-#endif /* !MBEDTLS_KEY_EXCHANGE_RSA_ENABLED
-          !MBEDTLS_KEY_EXCHANGE_RSA_PSK_ENABLED
-          !MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED
-          !MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED
-          !MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED
-          !MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED
-          !MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED */
+#endif /* MBEDTLS_KEY_EXCHANGE__WITH_CERT__ENABLED */
 
 int mbedtls_ssl_write_change_cipher_spec( mbedtls_ssl_context *ssl )
 {
@@ -7403,6 +7577,11 @@
 #if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
     handshake->sni_authmode = MBEDTLS_SSL_VERIFY_UNSET;
 #endif
+
+#if defined(MBEDTLS_X509_CRT_PARSE_C) && \
+    !defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
+    mbedtls_pk_init( &handshake->peer_pubkey );
+#endif
 }
 
 void mbedtls_ssl_transform_init( mbedtls_ssl_transform *transform )
@@ -7985,7 +8164,8 @@
         return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
     }
 
-    if( ( ret = ssl_session_copy( ssl->session_negotiate, session ) ) != 0 )
+    if( ( ret = mbedtls_ssl_session_copy( ssl->session_negotiate,
+                                          session ) ) != 0 )
         return( ret );
 
     ssl->handshake->resume = 1;
@@ -8839,12 +9019,17 @@
     if( ssl == NULL || ssl->session == NULL )
         return( NULL );
 
+#if defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
     return( ssl->session->peer_cert );
+#else
+    return( NULL );
+#endif /* MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
 }
 #endif /* MBEDTLS_X509_CRT_PARSE_C */
 
 #if defined(MBEDTLS_SSL_CLI_C)
-int mbedtls_ssl_get_session( const mbedtls_ssl_context *ssl, mbedtls_ssl_session *dst )
+int mbedtls_ssl_get_session( const mbedtls_ssl_context *ssl,
+                             mbedtls_ssl_session *dst )
 {
     if( ssl == NULL ||
         dst == NULL ||
@@ -8854,7 +9039,7 @@
         return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
     }
 
-    return( ssl_session_copy( dst, ssl->session ) );
+    return( mbedtls_ssl_session_copy( dst, ssl->session ) );
 }
 #endif /* MBEDTLS_SSL_CLI_C */
 
@@ -8918,6 +9103,12 @@
 #define SSL_SERIALIZED_SESSION_CONFIG_TICKET 0
 #endif /* MBEDTLS_SSL_SESSION_TICKETS */
 
+#if defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
+#define SSL_SERIALIZED_SESSION_CONFIG_KEEP_CRT 1
+#else
+#define SSL_SERIALIZED_SESSION_CONFIG_KEEP_CRT 0
+#endif /* MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
+
 #define SSL_SERIALIZED_SESSION_CONFIG_TIME_BIT          0
 #define SSL_SERIALIZED_SESSION_CONFIG_CRT_BIT           1
 #define SSL_SERIALIZED_SESSION_CONFIG_CLIENT_TICKET_BIT 2
@@ -8925,6 +9116,7 @@
 #define SSL_SERIALIZED_SESSION_CONFIG_TRUNC_HMAC_BIT    4
 #define SSL_SERIALIZED_SESSION_CONFIG_ETM_BIT           5
 #define SSL_SERIALIZED_SESSION_CONFIG_TICKET_BIT        6
+#define SSL_SERIALIZED_SESSION_CONFIG_KEEP_CRT_BIT      7
 
 #define SSL_SERIALIZED_SESSION_CONFIG_BITFLAG                           \
     ( (uint16_t) (                                                      \
@@ -8934,7 +9126,8 @@
         ( SSL_SERIALIZED_SESSION_CONFIG_MFL           << SSL_SERIALIZED_SESSION_CONFIG_MFL_BIT           ) | \
         ( SSL_SERIALIZED_SESSION_CONFIG_TRUNC_HMAC    << SSL_SERIALIZED_SESSION_CONFIG_TRUNC_HMAC_BIT    ) | \
         ( SSL_SERIALIZED_SESSION_CONFIG_ETM           << SSL_SERIALIZED_SESSION_CONFIG_ETM_BIT           ) | \
-        ( SSL_SERIALIZED_SESSION_CONFIG_TICKET        << SSL_SERIALIZED_SESSION_CONFIG_TICKET_BIT        ) ) )
+        ( SSL_SERIALIZED_SESSION_CONFIG_TICKET        << SSL_SERIALIZED_SESSION_CONFIG_TICKET_BIT        ) | \
+        ( SSL_SERIALIZED_SESSION_CONFIG_KEEP_CRT      << SSL_SERIALIZED_SESSION_CONFIG_KEEP_CRT_BIT      ) ) )
 
 static unsigned char ssl_serialized_session_header[] = {
     MBEDTLS_VERSION_MAJOR,
@@ -8967,7 +9160,11 @@
  *  opaque session_id[32];
  *  opaque master[48];           // fixed length in the standard
  *  uint32 verify_result;
- *  opaque peer_cert<0..2^24-1>; // length 0 means no peer cert
+ *  select (MBEDTLS_SSL_KEEP_PEER_CERTIFICATE) {
+ *      case enabled:  opaque peer_cert<0..2^24-1>; // length 0 means no cert
+ *      case disabled: uint8_t peer_cert_digest_type;
+ *                     opaque peer_cert_digest<0..2^8-1>;
+ *  }
  *  opaque ticket<0..2^24-1>;    // length 0 means no ticket
  *  uint32 ticket_lifetime;
  *  uint8 mfl_code;              // up to 255 according to standard
@@ -8989,8 +9186,10 @@
     uint64_t start;
 #endif
 #if defined(MBEDTLS_X509_CRT_PARSE_C)
+#if defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
     size_t cert_len;
 #endif
+#endif
 
     /*
      * Add version identifier
@@ -9060,6 +9259,7 @@
      * Peer's end-entity certificate
      */
 #if defined(MBEDTLS_X509_CRT_PARSE_C)
+#if defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
     if( session->peer_cert == NULL )
         cert_len = 0;
     else
@@ -9079,6 +9279,31 @@
             p += cert_len;
         }
     }
+
+#else /* MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
+    /* Digest of peer certificate */
+    if( session->peer_cert_digest != NULL )
+    {
+        used += 1 /* type */ + 1 /* length */ + session->peer_cert_digest_len;
+        if( used <= buf_len )
+        {
+            *p++ = (unsigned char) session->peer_cert_digest_type;
+            *p++ = (unsigned char) session->peer_cert_digest_len;
+            memcpy( p, session->peer_cert_digest,
+                    session->peer_cert_digest_len );
+            p += session->peer_cert_digest_len;
+        }
+    }
+    else
+    {
+        used += 2;
+        if( used <= buf_len )
+        {
+            *p++ = (unsigned char) MBEDTLS_MD_NONE;
+            *p++ = 0;
+        }
+    }
+#endif /* !MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
 #endif /* MBEDTLS_X509_CRT_PARSE_C */
 
     /*
@@ -9155,8 +9380,10 @@
     uint64_t start;
 #endif
 #if defined(MBEDTLS_X509_CRT_PARSE_C)
+#if defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
     size_t cert_len;
-#endif /* MBEDTLS_X509_CRT_PARSE_C */
+#endif
+#endif
 
     /*
      * Check version identifier
@@ -9219,7 +9446,11 @@
     /* Immediately clear invalid pointer values that have been read, in case
      * we exit early before we replaced them with valid ones. */
 #if defined(MBEDTLS_X509_CRT_PARSE_C)
+#if defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
     session->peer_cert = NULL;
+#else
+    session->peer_cert_digest = NULL;
+#endif /* !MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
 #endif
 #if defined(MBEDTLS_SSL_SESSION_TICKETS) && defined(MBEDTLS_SSL_CLI_C)
     session->ticket = NULL;
@@ -9229,6 +9460,7 @@
      * Peer certificate
      */
 #if defined(MBEDTLS_X509_CRT_PARSE_C)
+#if defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
     if( 3 > (size_t)( end - p ) )
         return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
 
@@ -9264,6 +9496,36 @@
 
         p += cert_len;
     }
+#else /* defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
+    /* Deserialize CRT digest from the end of the ticket. */
+    if( 2 > (size_t)( end - p ) )
+        return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
+
+    session->peer_cert_digest_type = (mbedtls_md_type_t) *p++;
+    session->peer_cert_digest_len  = (size_t) *p++;
+
+    if( session->peer_cert_digest_len != 0 )
+    {
+        const mbedtls_md_info_t *md_info =
+            mbedtls_md_info_from_type( session->peer_cert_digest_type );
+        if( md_info == NULL )
+            return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
+        if( session->peer_cert_digest_len != mbedtls_md_get_size( md_info ) )
+            return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
+
+        if( session->peer_cert_digest_len > (size_t)( end - p ) )
+            return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
+
+        session->peer_cert_digest =
+            mbedtls_calloc( 1, session->peer_cert_digest_len );
+        if( session->peer_cert_digest == NULL )
+            return( MBEDTLS_ERR_SSL_ALLOC_FAILED );
+
+        memcpy( session->peer_cert_digest, p,
+                session->peer_cert_digest_len );
+        p += session->peer_cert_digest_len;
+    }
+#endif /* MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
 #endif /* MBEDTLS_X509_CRT_PARSE_C */
 
     /*
@@ -10203,8 +10465,18 @@
 
 #if defined(MBEDTLS_SSL__ECP_RESTARTABLE)
     mbedtls_x509_crt_restart_free( &handshake->ecrs_ctx );
+    if( handshake->ecrs_peer_cert != NULL )
+    {
+        mbedtls_x509_crt_free( handshake->ecrs_peer_cert );
+        mbedtls_free( handshake->ecrs_peer_cert );
+    }
 #endif
 
+#if defined(MBEDTLS_X509_CRT_PARSE_C) &&        \
+    !defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
+    mbedtls_pk_free( &handshake->peer_pubkey );
+#endif /* MBEDTLS_X509_CRT_PARSE_C && !MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
+
 #if defined(MBEDTLS_SSL_PROTO_DTLS)
     mbedtls_free( handshake->verify_cookie );
     ssl_flight_free( handshake->flight );
@@ -10221,11 +10493,7 @@
         return;
 
 #if defined(MBEDTLS_X509_CRT_PARSE_C)
-    if( session->peer_cert != NULL )
-    {
-        mbedtls_x509_crt_free( session->peer_cert );
-        mbedtls_free( session->peer_cert );
-    }
+    ssl_clear_peer_cert( session );
 #endif
 
 #if defined(MBEDTLS_SSL_SESSION_TICKETS) && defined(MBEDTLS_SSL_CLI_C)
diff --git a/library/version_features.c b/library/version_features.c
index 245f957..5e9d923 100644
--- a/library/version_features.c
+++ b/library/version_features.c
@@ -456,6 +456,9 @@
 #if defined(MBEDTLS_SSL_FALLBACK_SCSV)
     "MBEDTLS_SSL_FALLBACK_SCSV",
 #endif /* MBEDTLS_SSL_FALLBACK_SCSV */
+#if defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
+    "MBEDTLS_SSL_KEEP_PEER_CERTIFICATE",
+#endif /* MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
 #if defined(MBEDTLS_SSL_HW_RECORD_ACCEL)
     "MBEDTLS_SSL_HW_RECORD_ACCEL",
 #endif /* MBEDTLS_SSL_HW_RECORD_ACCEL */
diff --git a/library/x509_crt.c b/library/x509_crt.c
index 97d4b95..e4a35f6 100644
--- a/library/x509_crt.c
+++ b/library/x509_crt.c
@@ -990,11 +990,13 @@
     /*
      * SubjectPublicKeyInfo
      */
+    crt->pk_raw.p = p;
     if( ( ret = mbedtls_pk_parse_subpubkey( &p, end, &crt->pk ) ) != 0 )
     {
         mbedtls_x509_crt_free( crt );
         return( ret );
     }
+    crt->pk_raw.len = p - crt->pk_raw.p;
 
     /*
      *  issuerUniqueID  [1]  IMPLICIT UniqueIdentifier OPTIONAL,
diff --git a/programs/ssl/query_config.c b/programs/ssl/query_config.c
index dbb6cc1..ab3c772 100644
--- a/programs/ssl/query_config.c
+++ b/programs/ssl/query_config.c
@@ -1258,6 +1258,14 @@
     }
 #endif /* MBEDTLS_SSL_FALLBACK_SCSV */
 
+#if defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
+    if( strcmp( "MBEDTLS_SSL_KEEP_PEER_CERTIFICATE", config ) == 0 )
+    {
+        MACRO_EXPANSION_TO_STR( MBEDTLS_SSL_KEEP_PEER_CERTIFICATE );
+        return( 0 );
+    }
+#endif /* MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
+
 #if defined(MBEDTLS_SSL_HW_RECORD_ACCEL)
     if( strcmp( "MBEDTLS_SSL_HW_RECORD_ACCEL", config ) == 0 )
     {
diff --git a/programs/ssl/ssl_client2.c b/programs/ssl/ssl_client2.c
index 9363316..d859101 100644
--- a/programs/ssl/ssl_client2.c
+++ b/programs/ssl/ssl_client2.c
@@ -494,6 +494,8 @@
 }
 
 #if defined(MBEDTLS_X509_CRT_PARSE_C)
+static unsigned char peer_crt_info[1024];
+
 /*
  * Enabled if debug_level > 1 in code below
  */
@@ -506,8 +508,14 @@
     ((void) data);
 
 #if !defined(MBEDTLS_X509_REMOVE_INFO)
-    mbedtls_printf( "\nVerify requested for (Depth %d):\n", depth );
     mbedtls_x509_crt_info( buf, sizeof( buf ) - 1, "", crt );
+    if( depth == 0 )
+        memcpy( peer_crt_info, buf, sizeof( buf ) );
+
+    if( opt.debug_level == 0 )
+        return( 0 );
+
+    mbedtls_printf( "\nVerify requested for (Depth %d):\n", depth );
     mbedtls_printf( "%s", buf );
 #else
     ((void) crt);
@@ -1641,8 +1649,8 @@
         mbedtls_ssl_conf_sig_hashes( &conf, ssl_sig_hashes_for_test );
     }
 
-    if( opt.debug_level > 0 )
-        mbedtls_ssl_conf_verify( &conf, my_verify, NULL );
+    mbedtls_ssl_conf_verify( &conf, my_verify, NULL );
+    memset( peer_crt_info, 0, sizeof( peer_crt_info ) );
 #endif /* MBEDTLS_X509_CRT_PARSE_C */
 
 #if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID)
@@ -2021,13 +2029,8 @@
         mbedtls_printf( " ok\n" );
 
 #if !defined(MBEDTLS_X509_REMOVE_INFO)
-    if( mbedtls_ssl_get_peer_cert( &ssl ) != NULL )
-    {
-        mbedtls_printf( "  . Peer certificate information    ...\n" );
-        mbedtls_x509_crt_info( (char *) buf, sizeof( buf ) - 1, "      ",
-                       mbedtls_ssl_get_peer_cert( &ssl ) );
-        mbedtls_printf( "%s\n", buf );
-    }
+    mbedtls_printf( "  . Peer certificate information    ...\n" );
+    mbedtls_printf( "%s\n", peer_crt_info );
 #endif /* !MBEDTLS_X509_REMOVE_INFO */
 #endif /* MBEDTLS_X509_CRT_PARSE_C */
 
@@ -2357,6 +2360,10 @@
         mbedtls_printf( "  . Restarting connection from same port..." );
         fflush( stdout );
 
+#if defined(MBEDTLS_X509_CRT_PARSE_C)
+        memset( peer_crt_info, 0, sizeof( peer_crt_info ) );
+#endif /* MBEDTLS_X509_CRT_PARSE_C */
+
         if( ( ret = mbedtls_ssl_session_reset( &ssl ) ) != 0 )
         {
             mbedtls_printf( " failed\n  ! mbedtls_ssl_session_reset returned -0x%x\n\n",
@@ -2511,6 +2518,10 @@
 
         mbedtls_printf( "  . Reconnecting with saved session..." );
 
+#if defined(MBEDTLS_X509_CRT_PARSE_C)
+        memset( peer_crt_info, 0, sizeof( peer_crt_info ) );
+#endif /* MBEDTLS_X509_CRT_PARSE_C */
+
         if( ( ret = mbedtls_ssl_session_reset( &ssl ) ) != 0 )
         {
             mbedtls_printf( " failed\n  ! mbedtls_ssl_session_reset returned -0x%x\n\n",
diff --git a/programs/x509/cert_app.c b/programs/x509/cert_app.c
index 8eded34..fd52719 100644
--- a/programs/x509/cert_app.c
+++ b/programs/x509/cert_app.c
@@ -467,9 +467,12 @@
         /*
          * 5. Print the certificate
          */
+#if !defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
+        mbedtls_printf( "  . Peer certificate information    ... skipped\n" );
+#else
         mbedtls_printf( "  . Peer certificate information    ...\n" );
         ret = mbedtls_x509_crt_info( (char *) buf, sizeof( buf ) - 1, "      ",
-                             ssl.session->peer_cert );
+                                     mbedtls_ssl_get_peer_cert( &ssl ) );
         if( ret == -1 )
         {
             mbedtls_printf( " failed\n  !  mbedtls_x509_crt_info returned %d\n\n", ret );
@@ -477,6 +480,7 @@
         }
 
         mbedtls_printf( "%s\n", buf );
+#endif /* MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
 
         mbedtls_ssl_close_notify( &ssl );
 
diff --git a/tests/scripts/all.sh b/tests/scripts/all.sh
index 8414d54..83e33fd 100755
--- a/tests/scripts/all.sh
+++ b/tests/scripts/all.sh
@@ -885,6 +885,22 @@
     if_build_succeeded tests/ssl-opt.sh -f "Max fragment length"
 }
 
+component_test_asan_remove_peer_certificate () {
+    msg "build: default config with MBEDTLS_SSL_KEEP_PEER_CERTIFICATE disabled (ASan build)"
+    scripts/config.pl unset MBEDTLS_SSL_KEEP_PEER_CERTIFICATE
+    CC=gcc cmake -D CMAKE_BUILD_TYPE:String=Asan .
+    make
+
+    msg "test: !MBEDTLS_SSL_KEEP_PEER_CERTIFICATE"
+    make test
+
+    msg "test: ssl-opt.sh, !MBEDTLS_SSL_KEEP_PEER_CERTIFICATE"
+    if_build_succeeded tests/ssl-opt.sh
+
+    msg "test: compat.sh, !MBEDTLS_SSL_KEEP_PEER_CERTIFICATE"
+    if_build_succeeded tests/compat.sh
+}
+
 component_test_no_max_fragment_length_small_ssl_out_content_len () {
     msg "build: no MFL extension, small SSL_OUT_CONTENT_LEN (ASan build)"
     scripts/config.pl unset MBEDTLS_SSL_MAX_FRAGMENT_LENGTH
diff --git a/tests/suites/test_suite_ssl.function b/tests/suites/test_suite_ssl.function
index c6dd564..fb77102 100644
--- a/tests/suites/test_suite_ssl.function
+++ b/tests/suites/test_suite_ssl.function
@@ -1,6 +1,7 @@
 /* BEGIN_HEADER */
 #include <mbedtls/ssl.h>
 #include <mbedtls/ssl_internal.h>
+#include <mbedtls/md.h>
 
 /*
  * Helper function setting up inverse record transformations
@@ -287,15 +288,40 @@
 #if defined(MBEDTLS_X509_CRT_PARSE_C) && defined(MBEDTLS_FS_IO)
     if( strlen( crt_file ) != 0 )
     {
+        mbedtls_x509_crt tmp_crt;
         int ret;
 
+        mbedtls_x509_crt_init( &tmp_crt );
+        ret = mbedtls_x509_crt_parse_file( &tmp_crt, crt_file );
+        if( ret != 0 )
+            return( ret );
+
+#if !defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
+        /* Calculate digest of temporary CRT. */
+        session->peer_cert_digest =
+            mbedtls_calloc( 1, MBEDTLS_SSL_PEER_CERT_DIGEST_DFL_LEN );
+        if( session->peer_cert_digest == NULL )
+            return( -1 );
+        ret = mbedtls_md( mbedtls_md_info_from_type(
+                              MBEDTLS_SSL_PEER_CERT_DIGEST_DFL_TYPE ),
+                          tmp_crt.raw.p, tmp_crt.raw.len,
+                          session->peer_cert_digest );
+        if( ret != 0 )
+            return( ret );
+        session->peer_cert_digest_type =
+            MBEDTLS_SSL_PEER_CERT_DIGEST_DFL_TYPE;
+        session->peer_cert_digest_len =
+            MBEDTLS_SSL_PEER_CERT_DIGEST_DFL_LEN;
+#else /* !MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
+        /* Move temporary CRT. */
         session->peer_cert = mbedtls_calloc( 1, sizeof( *session->peer_cert ) );
         if( session->peer_cert == NULL )
             return( -1 );
+        *session->peer_cert = tmp_crt;
+        memset( &tmp_crt, 0, sizeof( tmp_crt ) );
+#endif /* MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
 
-        ret = mbedtls_x509_crt_parse_file( session->peer_cert, crt_file );
-        if( ret != 0 )
-            return( ret );
+        mbedtls_x509_crt_free( &tmp_crt );
     }
 #else
     (void) crt_file;
@@ -681,6 +707,7 @@
                          restored.master, sizeof( original.master ) ) == 0 );
 
 #if defined(MBEDTLS_X509_CRT_PARSE_C)
+#if defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
     TEST_ASSERT( ( original.peer_cert == NULL ) ==
                  ( restored.peer_cert == NULL ) );
     if( original.peer_cert != NULL )
@@ -691,7 +718,21 @@
                              restored.peer_cert->raw.p,
                              original.peer_cert->raw.len ) == 0 );
     }
-#endif
+#else /* MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
+    TEST_ASSERT( original.peer_cert_digest_type ==
+                 restored.peer_cert_digest_type );
+    TEST_ASSERT( original.peer_cert_digest_len ==
+                 restored.peer_cert_digest_len );
+    TEST_ASSERT( ( original.peer_cert_digest == NULL ) ==
+                 ( restored.peer_cert_digest == NULL ) );
+    if( original.peer_cert_digest != NULL )
+    {
+        TEST_ASSERT( memcmp( original.peer_cert_digest,
+                             restored.peer_cert_digest,
+                             original.peer_cert_digest_len ) == 0 );
+    }
+#endif /* !MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
+#endif /* MBEDTLS_X509_CRT_PARSE_C */
     TEST_ASSERT( original.verify_result == restored.verify_result );
 
 #if defined(MBEDTLS_SSL_SESSION_TICKETS) && defined(MBEDTLS_SSL_CLI_C)