diff --git a/ChangeLog.d/default-curves.txt b/ChangeLog.d/default-curves.txt
new file mode 100644
index 0000000..bfb0fd0
--- /dev/null
+++ b/ChangeLog.d/default-curves.txt
@@ -0,0 +1,9 @@
+Default behavior changes
+   * Some default policies for X.509 certificate verification and TLS have
+     changed: curves and hashes weaker than 255 bits are no longer accepted
+     by default. The default order in TLS now favors faster curves over larger
+     curves.
+
+Removals
+   * Remove the compile-time option
+     MBEDTLS_TLS_DEFAULT_ALLOW_SHA1_IN_KEY_EXCHANGE.
diff --git a/ChangeLog.d/ecp-window-size.txt b/ChangeLog.d/ecp-window-size.txt
new file mode 100644
index 0000000..909d4e8
--- /dev/null
+++ b/ChangeLog.d/ecp-window-size.txt
@@ -0,0 +1,3 @@
+Changes
+   * Reduce the default value of MBEDTLS_ECP_WINDOW_SIZE. This reduces RAM usage
+     during ECC operations at a negligible performance cost.
diff --git a/ChangeLog.d/mbedtls_debug_print_mpi.txt b/ChangeLog.d/mbedtls_debug_print_mpi.txt
new file mode 100644
index 0000000..d1b4f5b
--- /dev/null
+++ b/ChangeLog.d/mbedtls_debug_print_mpi.txt
@@ -0,0 +1,5 @@
+Bugfix
+   * Fix a crash in mbedtls_mpi_debug_mpi on a bignum having 0 limbs. This
+     could notably be triggered by setting the TLS debug level to 3 or above
+     and using a Montgomery curve for the key exchange. Reported by lhuang04
+     in #4578. Fixes #4608.
diff --git a/docs/3.0-migration-guide.d/default-curves.md b/docs/3.0-migration-guide.d/default-curves.md
new file mode 100644
index 0000000..928130d
--- /dev/null
+++ b/docs/3.0-migration-guide.d/default-curves.md
@@ -0,0 +1,25 @@
+Strengthen default algorithm selection for X.509 and TLS
+--------------------------------------------------------
+
+The default X.509 verification profile (`mbedtls_x509_crt_profile_default`) and the default curve and hash selection in TLS have changed. They are now aligned, except that the X.509 profile only lists curves that support signature verification.
+
+Hashes and curves weaker than 255 bits (security strength less than 128 bits) are no longer accepted by default. The following hashes have been removed: SHA-1 (formerly only accepted for key exchanges but not for certificate signatures), SHA-224 (weaker hashes were already not accepted). The following curves have been removed: secp192r1, secp224r1, secp192k1, secp224k1.
+
+The compile-time options `MBEDTLS_TLS_DEFAULT_ALLOW_SHA1_IN_CERTIFICATES` and `MBEDTLS_TLS_DEFAULT_ALLOW_SHA1_IN_KEY_EXCHANGE` are no longer available.
+
+The curve secp256k1 has also been removed from the default X.509 and TLS profiles. [RFC 8422](https://datatracker.ietf.org/doc/html/rfc8422#section-5.1.1) deprecates it in TLS, and it is very rarely used, although it is not known to be weak at the time of writing.
+
+If you still need to accept certificates signed with algorithms that have been removed from the default profile, call `mbedtls_x509_crt_verify_with_profile` instead of `mbedtls_x509_crt_verify` and pass a profile that allows the curves and hashes you want. For example, to allow SHA-224:
+```
+mbedtls_x509_crt_profile my_profile = mbedtls_x509_crt_profile_default;
+my_profile.allowed_mds |= MBEDTLS_X509_ID_FLAG( MBEDTLS_MD_SHA224 );
+```
+
+If you still need to allow hashes and curves in TLS that have been removed from the default configuration, call `mbedtls_ssl_conf_sig_hashes()` and `mbedtls_ssl_conf_curves()` with the desired lists.
+
+TLS now favors faster curves over larger curves
+-----------------------------------------------
+
+The default preference order for curves in TLS now favors resource usage (performance and memory consumption) over size. The exact order is unspecified and may change, but generally you can expect 256-bit curves to be preferred over larger curves.
+
+If you prefer a different order, call `mbedtls_ssl_conf_curves()` when configuring a TLS connection.
diff --git a/docs/3.0-migration-guide.md b/docs/3.0-migration-guide.md
index d76cc17..1541c7a 100644
--- a/docs/3.0-migration-guide.md
+++ b/docs/3.0-migration-guide.md
@@ -65,31 +65,6 @@
 function that's now in a private header, please reach out on the mailing list
 and explain your need; we'll consider adding a new API in a future version.
 
-Remove the option to allow SHA-1 by default in certificates
------------------------------------------------------------
-
-This does not affect users who use the default `config.h`, as this option was
-already off by default.
-
-If you used to enable `MBEDTLS_TLS_DEFAULT_ALLOW_SHA1_IN_CERTIFICATES` in your
-`config.h`, first please take a moment to consider whether you really still
-want to accept certificates signed with SHA-1 as those are considered insecure
-and no CA has issued them for a while. If you really need to allow SHA-1 in
-certificates, please set up a custom profile as follows:
-
-```
-const mbedtls_x509_crt_profile mbedtls_x509_crt_custom = {
-    MBEDTLS_X509_ID_FLAG( MBEDTLS_MD_SHA1 ) |
-    MBEDTLS_X509_ID_FLAG( /* other hash */ ) /* | etc */,
-    0xFFFFFFF,  /* Or specific PK algs */
-    0xFFFFFFF,  /* Or specific curves */
-    2048        /* Or another RSA min bitlen */
-};
-```
-Then pass it to `mbedtls_x509_crt_verify_with_profile()` if you're verifying
-a certificate chain directly, or to `mbedtls_ssl_conf_cert_profile()` if the
-verification happens during a TLS handshake.
-
 Remove the certs module from the library
 ----------------------------------------
 
diff --git a/include/mbedtls/config.h b/include/mbedtls/config.h
index 1a9c924..c37f61c 100644
--- a/include/mbedtls/config.h
+++ b/include/mbedtls/config.h
@@ -3033,7 +3033,7 @@
 //#define MBEDTLS_HMAC_DRBG_MAX_SEED_INPUT      384 /**< Maximum size of (re)seed buffer */
 
 /* ECP options */
-//#define MBEDTLS_ECP_WINDOW_SIZE            6 /**< Maximum window size used */
+//#define MBEDTLS_ECP_WINDOW_SIZE            4 /**< Maximum window size used */
 //#define MBEDTLS_ECP_FIXED_POINT_OPTIM      1 /**< Enable fixed-point speed-up */
 
 /* Entropy options */
@@ -3215,23 +3215,6 @@
 //#define MBEDTLS_X509_MAX_FILE_PATH_LEN     512 /**< Maximum length of a path/filename string in bytes including the null terminator character ('\0'). */
 
 /**
- * Allow SHA-1 in the default TLS configuration for TLS 1.2 handshake
- * signature and ciphersuite selection. Without this build-time option, SHA-1
- * support must be activated explicitly through mbedtls_ssl_conf_sig_hashes.
- * The use of SHA-1 in TLS <= 1.1 and in HMAC-SHA-1 is always allowed by
- * default. At the time of writing, there is no practical attack on the use
- * of SHA-1 in handshake signatures, hence this option is turned on by default
- * to preserve compatibility with existing peers, but the general
- * warning applies nonetheless:
- *
- * \warning   SHA-1 is considered a weak message digest and its use constitutes
- *            a security risk. If possible, we recommend avoiding dependencies
- *            on it, and considering stronger message digests instead.
- *
- */
-#define MBEDTLS_TLS_DEFAULT_ALLOW_SHA1_IN_KEY_EXCHANGE
-
-/**
  * Uncomment the macro to let mbed TLS use your alternate implementation of
  * mbedtls_platform_zeroize(). This replaces the default implementation in
  * platform_util.c.
diff --git a/include/mbedtls/ecp.h b/include/mbedtls/ecp.h
index 75ad808..db84c10 100644
--- a/include/mbedtls/ecp.h
+++ b/include/mbedtls/ecp.h
@@ -255,7 +255,8 @@
 #if !defined(MBEDTLS_ECP_WINDOW_SIZE)
 /*
  * Maximum "window" size used for point multiplication.
- * Default: 6.
+ * Default: a point where higher memory usage yields disminishing performance
+ *          returns.
  * Minimum value: 2. Maximum value: 7.
  *
  * Result is an array of at most ( 1 << ( MBEDTLS_ECP_WINDOW_SIZE - 1 ) )
@@ -272,7 +273,7 @@
  *      224       475     475     453     398     342
  *      192       640     640     633     587     476
  */
-#define MBEDTLS_ECP_WINDOW_SIZE    6   /**< The maximum window size used. */
+#define MBEDTLS_ECP_WINDOW_SIZE    4   /**< The maximum window size used. */
 #endif /* MBEDTLS_ECP_WINDOW_SIZE */
 
 #if !defined(MBEDTLS_ECP_FIXED_POINT_OPTIM)
@@ -505,8 +506,7 @@
 
 /**
  * \brief           This function retrieves the information defined in
- *                  mbedtls_ecp_curve_info() for all supported curves in order
- *                  of preference.
+ *                  mbedtls_ecp_curve_info() for all supported curves.
  *
  * \note            This function returns information about all curves
  *                  supported by the library. Some curves may not be
diff --git a/include/mbedtls/ssl.h b/include/mbedtls/ssl.h
index 1a963c5..32ed638 100644
--- a/include/mbedtls/ssl.h
+++ b/include/mbedtls/ssl.h
@@ -2901,7 +2901,6 @@
 #if defined(MBEDTLS_ECP_C)
 /**
  * \brief          Set the allowed curves in order of preference.
- *                 (Default: all defined curves.)
  *
  *                 On server: this only affects selection of the ECDHE curve;
  *                 the curves used for ECDH and ECDSA are determined by the
@@ -2922,6 +2921,19 @@
  * \note           This list should be ordered by decreasing preference
  *                 (preferred curve first).
  *
+ * \note           The default list is the same set of curves that
+ *                 #mbedtls_x509_crt_profile_default allows, plus
+ *                 ECDHE-only curves selected according to the same criteria.
+ *                 The order favors curves with the lowest resource usage.
+ *
+ * \note           New minor versions of Mbed TLS may extend this list,
+ *                 for example if new curves are added to the library.
+ *                 New minor versions of Mbed TLS will not remove items
+ *                 from this list unless serious security concerns require it.
+ *                 New minor versions of Mbed TLS may change the order in
+ *                 keeping with the general principle of favoring the lowest
+ *                 resource usage.
+ *
  * \param conf     SSL configuration
  * \param curves   Ordered list of allowed curves,
  *                 terminated by MBEDTLS_ECP_DP_NONE.
@@ -2933,7 +2945,6 @@
 #if defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
 /**
  * \brief          Set the allowed hashes for signatures during the handshake.
- *                 (Default: all available hashes except MD5.)
  *
  * \note           This only affects which hashes are offered and can be used
  *                 for signatures during the handshake. Hashes for message
@@ -2945,6 +2956,18 @@
  * \note           This list should be ordered by decreasing preference
  *                 (preferred hash first).
  *
+ * \note           By default, all supported hashes whose length is at least
+ *                 256 bits are allowed. This is the same set as the default
+ *                 for certificate verification
+ *                 (#mbedtls_x509_crt_profile_default).
+ *                 The preference order is currently unspecified and may
+ *                 change in future versions.
+ *
+ * \note           New minor versions of Mbed TLS may extend this list,
+ *                 for example if new curves are added to the library.
+ *                 New minor versions of Mbed TLS will not remove items
+ *                 from this list unless serious security concerns require it.
+ *
  * \param conf     SSL configuration
  * \param hashes   Ordered list of allowed signature hashes,
  *                 terminated by \c MBEDTLS_MD_NONE.
diff --git a/include/mbedtls/x509_crt.h b/include/mbedtls/x509_crt.h
index 5c5509c..340c522 100644
--- a/include/mbedtls/x509_crt.h
+++ b/include/mbedtls/x509_crt.h
@@ -332,12 +332,22 @@
 /**
  * Default security profile. Should provide a good balance between security
  * and compatibility with current deployments.
+ *
+ * This profile permits:
+ * - SHA2 hashes with at least 256 bits: SHA-256, SHA-384, SHA-512.
+ * - Elliptic curves with 255 bits and above except secp256k1.
+ * - RSA with 2048 bits and above.
+ *
+ * New minor versions of Mbed TLS may extend this profile, for example if
+ * new algorithms are added to the library. New minor versions of Mbed TLS will
+ * not reduce this profile unless serious security concerns require it.
  */
 extern const mbedtls_x509_crt_profile mbedtls_x509_crt_profile_default;
 
 /**
  * Expected next default profile. Recommended for new deployments.
- * Currently targets a 128-bit security level, except for RSA-2048.
+ * Currently targets a 128-bit security level, except for allowing RSA-2048.
+ * This profile may change at any time.
  */
 extern const mbedtls_x509_crt_profile mbedtls_x509_crt_profile_next;
 
diff --git a/library/debug.c b/library/debug.c
index 4be2cba..fa60d13 100644
--- a/library/debug.c
+++ b/library/debug.c
@@ -220,8 +220,8 @@
                       const char *text, const mbedtls_mpi *X )
 {
     char str[DEBUG_BUF_SIZE];
-    int j, k, zeros = 1;
-    size_t i, n, idx = 0;
+    size_t bitlen;
+    size_t idx = 0;
 
     if( NULL == ssl              ||
         NULL == ssl->conf        ||
@@ -232,55 +232,43 @@
         return;
     }
 
-    for( n = X->n - 1; n > 0; n-- )
-        if( X->p[n] != 0 )
-            break;
+    bitlen = mbedtls_mpi_bitlen( X );
 
-    for( j = ( sizeof(mbedtls_mpi_uint) << 3 ) - 1; j >= 0; j-- )
-        if( ( ( X->p[n] >> j ) & 1 ) != 0 )
-            break;
-
-    mbedtls_snprintf( str + idx, sizeof( str ) - idx, "value of '%s' (%d bits) is:\n",
-              text, (int) ( ( n * ( sizeof(mbedtls_mpi_uint) << 3 ) ) + j + 1 ) );
-
+    mbedtls_snprintf( str, sizeof( str ), "value of '%s' (%u bits) is:\n",
+                      text, (unsigned) bitlen );
     debug_send_line( ssl, level, file, line, str );
 
-    idx = 0;
-    for( i = n + 1, j = 0; i > 0; i-- )
+    if( bitlen == 0 )
     {
-        if( zeros && X->p[i - 1] == 0 )
-            continue;
-
-        for( k = sizeof( mbedtls_mpi_uint ) - 1; k >= 0; k-- )
+        str[0] = ' '; str[1] = '0'; str[2] = '0';
+        idx = 3;
+    }
+    else
+    {
+        int n;
+        for( n = (int) ( ( bitlen - 1 ) / 8 ); n >= 0; n-- )
         {
-            if( zeros && ( ( X->p[i - 1] >> ( k << 3 ) ) & 0xFF ) == 0 )
-                continue;
-            else
-                zeros = 0;
-
-            if( j % 16 == 0 )
+            size_t limb_offset = n / sizeof( mbedtls_mpi_uint );
+            size_t offset_in_limb = n % sizeof( mbedtls_mpi_uint );
+            unsigned char octet =
+                ( X->p[limb_offset] >> ( offset_in_limb * 8 ) ) & 0xff;
+            mbedtls_snprintf( str + idx, sizeof( str ) - idx, " %02x", octet );
+            idx += 3;
+            /* Wrap lines after 16 octets that each take 3 columns */
+            if( idx >= 3 * 16 )
             {
-                if( j > 0 )
-                {
-                    mbedtls_snprintf( str + idx, sizeof( str ) - idx, "\n" );
-                    debug_send_line( ssl, level, file, line, str );
-                    idx = 0;
-                }
+                mbedtls_snprintf( str + idx, sizeof( str ) - idx, "\n" );
+                debug_send_line( ssl, level, file, line, str );
+                idx = 0;
             }
-
-            idx += mbedtls_snprintf( str + idx, sizeof( str ) - idx, " %02x", (unsigned int)
-                             ( X->p[i - 1] >> ( k << 3 ) ) & 0xFF );
-
-            j++;
         }
-
     }
 
-    if( zeros == 1 )
-        idx += mbedtls_snprintf( str + idx, sizeof( str ) - idx, " 00" );
-
-    mbedtls_snprintf( str + idx, sizeof( str ) - idx, "\n" );
-    debug_send_line( ssl, level, file, line, str );
+    if( idx != 0 )
+    {
+        mbedtls_snprintf( str + idx, sizeof( str ) - idx, "\n" );
+        debug_send_line( ssl, level, file, line, str );
+    }
 }
 #endif /* MBEDTLS_BIGNUM_C */
 
diff --git a/library/ecp.c b/library/ecp.c
index 8f6e988..3dc1378 100644
--- a/library/ecp.c
+++ b/library/ecp.c
@@ -349,9 +349,9 @@
  *  - readable name
  *
  * Curves are listed in order: largest curves first, and for a given size,
- * fastest curves first. This provides the default order for the SSL module.
+ * fastest curves first.
  *
- * Reminder: update profiles in x509_crt.c when adding a new curves!
+ * Reminder: update profiles in x509_crt.c and ssl_tls.c when adding a new curve!
  */
 static const mbedtls_ecp_curve_info ecp_supported_curves[] =
 {
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index 1bfbc84..5787026 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -6069,6 +6069,11 @@
 }
 
 #if defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
+/* The selection should be the same as mbedtls_x509_crt_profile_default in
+ * x509_crt.c. Here, the order matters. Currently we favor stronger hashes,
+ * for no fundamental reason.
+ * See the documentation of mbedtls_ssl_conf_curves() for what we promise
+ * about this list. */
 static int ssl_preset_default_hashes[] = {
 #if defined(MBEDTLS_SHA512_C)
     MBEDTLS_MD_SHA512,
@@ -6079,16 +6084,46 @@
 #if defined(MBEDTLS_SHA256_C)
     MBEDTLS_MD_SHA256,
 #endif
-#if defined(MBEDTLS_SHA224_C)
-    MBEDTLS_MD_SHA224,
-#endif
-#if defined(MBEDTLS_SHA1_C) && defined(MBEDTLS_TLS_DEFAULT_ALLOW_SHA1_IN_KEY_EXCHANGE)
-    MBEDTLS_MD_SHA1,
-#endif
     MBEDTLS_MD_NONE
 };
 #endif
 
+#if defined(MBEDTLS_ECP_C)
+/* The selection should be the same as mbedtls_x509_crt_profile_default in
+ * x509_crt.c, plus Montgomery curves for ECDHE. Here, the order matters:
+ * curves with a lower resource usage come first.
+ * See the documentation of mbedtls_ssl_conf_curves() for what we promise
+ * about this list.
+ */
+static mbedtls_ecp_group_id ssl_preset_default_curves[] = {
+#if defined(MBEDTLS_ECP_DP_CURVE25519_ENABLED)
+    MBEDTLS_ECP_DP_CURVE25519,
+#endif
+#if defined(MBEDTLS_ECP_DP_SECP256R1_ENABLED)
+    MBEDTLS_ECP_DP_SECP256R1,
+#endif
+#if defined(MBEDTLS_ECP_DP_SECP384R1_ENABLED)
+    MBEDTLS_ECP_DP_SECP384R1,
+#endif
+#if defined(MBEDTLS_ECP_DP_CURVE448_ENABLED)
+    MBEDTLS_ECP_DP_CURVE448,
+#endif
+#if defined(MBEDTLS_ECP_DP_SECP521R1_ENABLED)
+    MBEDTLS_ECP_DP_SECP521R1,
+#endif
+#if defined(MBEDTLS_ECP_DP_BP256R1_ENABLED)
+    MBEDTLS_ECP_DP_BP256R1,
+#endif
+#if defined(MBEDTLS_ECP_DP_BP384R1_ENABLED)
+    MBEDTLS_ECP_DP_BP384R1,
+#endif
+#if defined(MBEDTLS_ECP_DP_BP512R1_ENABLED)
+    MBEDTLS_ECP_DP_BP512R1,
+#endif
+    MBEDTLS_ECP_DP_NONE
+};
+#endif
+
 static int ssl_preset_suiteb_ciphersuites[] = {
     MBEDTLS_TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,
     MBEDTLS_TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,
@@ -6252,7 +6287,7 @@
 #endif
 
 #if defined(MBEDTLS_ECP_C)
-            conf->curve_list = mbedtls_ecp_grp_id_list();
+            conf->curve_list = ssl_preset_default_curves;
 #endif
 
 #if defined(MBEDTLS_DHM_C) && defined(MBEDTLS_SSL_CLI_C)
diff --git a/library/x509_crt.c b/library/x509_crt.c
index d4e0ffd..f12ac6b 100644
--- a/library/x509_crt.c
+++ b/library/x509_crt.c
@@ -95,33 +95,43 @@
  */
 #define X509_MAX_VERIFY_CHAIN_SIZE    ( MBEDTLS_X509_MAX_INTERMEDIATE_CA + 2 )
 
-/*
- * Default profile
- */
+/* Default profile. Do not remove items unless there are serious security
+ * concerns. */
 const mbedtls_x509_crt_profile mbedtls_x509_crt_profile_default =
 {
-    /* Only SHA-2 hashes */
-    MBEDTLS_X509_ID_FLAG( MBEDTLS_MD_SHA224 ) |
-    MBEDTLS_X509_ID_FLAG( MBEDTLS_MD_SHA256 ) |
-    MBEDTLS_X509_ID_FLAG( MBEDTLS_MD_SHA384 ) |
-    MBEDTLS_X509_ID_FLAG( MBEDTLS_MD_SHA512 ),
-    0xFFFFFFF, /* Any PK alg    */
-    0xFFFFFFF, /* Any curve     */
-    2048,
-};
-
-/*
- * Next-default profile
- */
-const mbedtls_x509_crt_profile mbedtls_x509_crt_profile_next =
-{
-    /* Hashes from SHA-256 and above */
+    /* Hashes from SHA-256 and above. Note that this selection
+     * should be aligned with ssl_preset_default_hashes in ssl_tls.c. */
     MBEDTLS_X509_ID_FLAG( MBEDTLS_MD_SHA256 ) |
     MBEDTLS_X509_ID_FLAG( MBEDTLS_MD_SHA384 ) |
     MBEDTLS_X509_ID_FLAG( MBEDTLS_MD_SHA512 ),
     0xFFFFFFF, /* Any PK alg    */
 #if defined(MBEDTLS_ECP_C)
-    /* Curves at or above 128-bit security level */
+    /* Curves at or above 128-bit security level. Note that this selection
+     * should be aligned with ssl_preset_default_curves in ssl_tls.c. */
+    MBEDTLS_X509_ID_FLAG( MBEDTLS_ECP_DP_SECP256R1 ) |
+    MBEDTLS_X509_ID_FLAG( MBEDTLS_ECP_DP_SECP384R1 ) |
+    MBEDTLS_X509_ID_FLAG( MBEDTLS_ECP_DP_SECP521R1 ) |
+    MBEDTLS_X509_ID_FLAG( MBEDTLS_ECP_DP_BP256R1 ) |
+    MBEDTLS_X509_ID_FLAG( MBEDTLS_ECP_DP_BP384R1 ) |
+    MBEDTLS_X509_ID_FLAG( MBEDTLS_ECP_DP_BP512R1 ) |
+    0,
+#else
+    0,
+#endif
+    2048,
+};
+
+/* Next-generation profile. Currently identical to the default, but may
+ * be tightened at any time. */
+const mbedtls_x509_crt_profile mbedtls_x509_crt_profile_next =
+{
+    /* Hashes from SHA-256 and above. */
+    MBEDTLS_X509_ID_FLAG( MBEDTLS_MD_SHA256 ) |
+    MBEDTLS_X509_ID_FLAG( MBEDTLS_MD_SHA384 ) |
+    MBEDTLS_X509_ID_FLAG( MBEDTLS_MD_SHA512 ),
+    0xFFFFFFF, /* Any PK alg    */
+#if defined(MBEDTLS_ECP_C)
+    /* Curves at or above 128-bit security level. */
     MBEDTLS_X509_ID_FLAG( MBEDTLS_ECP_DP_SECP256R1 ) |
     MBEDTLS_X509_ID_FLAG( MBEDTLS_ECP_DP_SECP384R1 ) |
     MBEDTLS_X509_ID_FLAG( MBEDTLS_ECP_DP_SECP521R1 ) |
diff --git a/tests/ssl-opt.sh b/tests/ssl-opt.sh
index 89eece6..681a6ef 100755
--- a/tests/ssl-opt.sh
+++ b/tests/ssl-opt.sh
@@ -1008,7 +1008,7 @@
 run_test_psa_force_curve() {
     requires_config_enabled MBEDTLS_USE_PSA_CRYPTO
     run_test    "PSA - ECDH with $1" \
-                "$P_SRV debug_level=4 force_version=tls1_2" \
+                "$P_SRV debug_level=4 force_version=tls1_2 curves=$1" \
                 "$P_CLI debug_level=4 force_version=tls1_2 force_ciphersuite=TLS-ECDHE-RSA-WITH-AES-128-GCM-SHA256 curves=$1" \
                 0 \
                 -c "Successfully setup PSA-based decryption cipher context" \
@@ -1233,7 +1233,7 @@
 
 # Checks that:
 # - things work with all ciphersuites active (used with config-full in all.sh)
-# - the expected (highest security) parameters are selected
+# - the expected parameters are selected
 #   ("signature_algorithm ext: 6" means SHA-512 (highest common hash))
 run_test    "Default" \
             "$P_SRV debug_level=3" \
@@ -1242,7 +1242,7 @@
             -s "Protocol is TLSv1.2" \
             -s "Ciphersuite is TLS-ECDHE-RSA-WITH-CHACHA20-POLY1305-SHA256" \
             -s "client hello v3, signature_algorithm ext: 6" \
-            -s "ECDHE curve: secp521r1" \
+            -s "ECDHE curve: x25519" \
             -S "error" \
             -C "error"
 
@@ -5743,9 +5743,12 @@
 
 # Tests for restartable ECC
 
+# Force the use of a curve that supports restartable ECC (secp256r1).
+
 requires_config_enabled MBEDTLS_ECP_RESTARTABLE
+requires_config_enabled MBEDTLS_ECP_DP_SECP256R1_ENABLED
 run_test    "EC restart: TLS, default" \
-            "$P_SRV auth_mode=required" \
+            "$P_SRV curves=secp256r1 auth_mode=required" \
             "$P_CLI force_ciphersuite=TLS-ECDHE-ECDSA-WITH-AES-128-GCM-SHA256 \
              key_file=data_files/server5.key crt_file=data_files/server5.crt  \
              debug_level=1" \
@@ -5756,8 +5759,9 @@
             -C "mbedtls_pk_sign.*4b00"
 
 requires_config_enabled MBEDTLS_ECP_RESTARTABLE
+requires_config_enabled MBEDTLS_ECP_DP_SECP256R1_ENABLED
 run_test    "EC restart: TLS, max_ops=0" \
-            "$P_SRV auth_mode=required" \
+            "$P_SRV curves=secp256r1 auth_mode=required" \
             "$P_CLI force_ciphersuite=TLS-ECDHE-ECDSA-WITH-AES-128-GCM-SHA256 \
              key_file=data_files/server5.key crt_file=data_files/server5.crt  \
              debug_level=1 ec_max_ops=0" \
@@ -5768,8 +5772,9 @@
             -C "mbedtls_pk_sign.*4b00"
 
 requires_config_enabled MBEDTLS_ECP_RESTARTABLE
+requires_config_enabled MBEDTLS_ECP_DP_SECP256R1_ENABLED
 run_test    "EC restart: TLS, max_ops=65535" \
-            "$P_SRV auth_mode=required" \
+            "$P_SRV curves=secp256r1 auth_mode=required" \
             "$P_CLI force_ciphersuite=TLS-ECDHE-ECDSA-WITH-AES-128-GCM-SHA256 \
              key_file=data_files/server5.key crt_file=data_files/server5.crt  \
              debug_level=1 ec_max_ops=65535" \
@@ -5780,8 +5785,9 @@
             -C "mbedtls_pk_sign.*4b00"
 
 requires_config_enabled MBEDTLS_ECP_RESTARTABLE
+requires_config_enabled MBEDTLS_ECP_DP_SECP256R1_ENABLED
 run_test    "EC restart: TLS, max_ops=1000" \
-            "$P_SRV auth_mode=required" \
+            "$P_SRV curves=secp256r1 auth_mode=required" \
             "$P_CLI force_ciphersuite=TLS-ECDHE-ECDSA-WITH-AES-128-GCM-SHA256 \
              key_file=data_files/server5.key crt_file=data_files/server5.crt  \
              debug_level=1 ec_max_ops=1000" \
@@ -5792,8 +5798,9 @@
             -c "mbedtls_pk_sign.*4b00"
 
 requires_config_enabled MBEDTLS_ECP_RESTARTABLE
+requires_config_enabled MBEDTLS_ECP_DP_SECP256R1_ENABLED
 run_test    "EC restart: TLS, max_ops=1000, badsign" \
-            "$P_SRV auth_mode=required \
+            "$P_SRV curves=secp256r1 auth_mode=required \
              crt_file=data_files/server5-badsign.crt \
              key_file=data_files/server5.key" \
             "$P_CLI force_ciphersuite=TLS-ECDHE-ECDSA-WITH-AES-128-GCM-SHA256 \
@@ -5809,8 +5816,9 @@
             -c "X509 - Certificate verification failed"
 
 requires_config_enabled MBEDTLS_ECP_RESTARTABLE
+requires_config_enabled MBEDTLS_ECP_DP_SECP256R1_ENABLED
 run_test    "EC restart: TLS, max_ops=1000, auth_mode=optional badsign" \
-            "$P_SRV auth_mode=required \
+            "$P_SRV curves=secp256r1 auth_mode=required \
              crt_file=data_files/server5-badsign.crt \
              key_file=data_files/server5.key" \
             "$P_CLI force_ciphersuite=TLS-ECDHE-ECDSA-WITH-AES-128-GCM-SHA256 \
@@ -5826,8 +5834,9 @@
             -C "X509 - Certificate verification failed"
 
 requires_config_enabled MBEDTLS_ECP_RESTARTABLE
+requires_config_enabled MBEDTLS_ECP_DP_SECP256R1_ENABLED
 run_test    "EC restart: TLS, max_ops=1000, auth_mode=none badsign" \
-            "$P_SRV auth_mode=required \
+            "$P_SRV curves=secp256r1 auth_mode=required \
              crt_file=data_files/server5-badsign.crt \
              key_file=data_files/server5.key" \
             "$P_CLI force_ciphersuite=TLS-ECDHE-ECDSA-WITH-AES-128-GCM-SHA256 \
@@ -5843,8 +5852,9 @@
             -C "X509 - Certificate verification failed"
 
 requires_config_enabled MBEDTLS_ECP_RESTARTABLE
+requires_config_enabled MBEDTLS_ECP_DP_SECP256R1_ENABLED
 run_test    "EC restart: DTLS, max_ops=1000" \
-            "$P_SRV auth_mode=required dtls=1" \
+            "$P_SRV curves=secp256r1 auth_mode=required dtls=1" \
             "$P_CLI force_ciphersuite=TLS-ECDHE-ECDSA-WITH-AES-128-GCM-SHA256 \
              key_file=data_files/server5.key crt_file=data_files/server5.crt  \
              dtls=1 debug_level=1 ec_max_ops=1000" \
@@ -5855,8 +5865,9 @@
             -c "mbedtls_pk_sign.*4b00"
 
 requires_config_enabled MBEDTLS_ECP_RESTARTABLE
+requires_config_enabled MBEDTLS_ECP_DP_SECP256R1_ENABLED
 run_test    "EC restart: TLS, max_ops=1000 no client auth" \
-            "$P_SRV" \
+            "$P_SRV curves=secp256r1" \
             "$P_CLI force_ciphersuite=TLS-ECDHE-ECDSA-WITH-AES-128-GCM-SHA256 \
              debug_level=1 ec_max_ops=1000" \
             0 \
@@ -5866,8 +5877,9 @@
             -C "mbedtls_pk_sign.*4b00"
 
 requires_config_enabled MBEDTLS_ECP_RESTARTABLE
+requires_config_enabled MBEDTLS_ECP_DP_SECP256R1_ENABLED
 run_test    "EC restart: TLS, max_ops=1000, ECDHE-PSK" \
-            "$P_SRV psk=abc123" \
+            "$P_SRV curves=secp256r1 psk=abc123" \
             "$P_CLI force_ciphersuite=TLS-ECDHE-PSK-WITH-AES-128-CBC-SHA256 \
              psk=abc123 debug_level=1 ec_max_ops=1000" \
             0 \
diff --git a/tests/suites/test_suite_debug.data b/tests/suites/test_suite_debug.data
index 0935c12..4a1a1be 100644
--- a/tests/suites/test_suite_debug.data
+++ b/tests/suites/test_suite_debug.data
@@ -37,6 +37,27 @@
 Debug print buffer #5
 mbedtls_debug_print_buf:"MyFile":999:"Test return value":"000102030405060708090A0B0C0D0E0F101112131415161718191A1B1C1D1E1F202122232425262728292A2B2C2D2E2F30":"MyFile(0999)\: dumping 'Test return value' (49 bytes)\nMyFile(0999)\: 0000\:  00 01 02 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 0f  ................\nMyFile(0999)\: 0010\:  10 11 12 13 14 15 16 17 18 19 1a 1b 1c 1d 1e 1f  ................\nMyFile(0999)\: 0020\:  20 21 22 23 24 25 26 27 28 29 2a 2b 2c 2d 2e 2f   !"#$%&'()*+,-./\nMyFile(0999)\: 0030\:  30                                               0\n"
 
+Debug print mbedtls_mpi: 0 (empty representation)
+mbedtls_debug_print_mpi:16:"":"MyFile":999:"VALUE":"MyFile(0999)\: value of 'VALUE' (0 bits) is\:\nMyFile(0999)\:  00\n"
+
+Debug print mbedtls_mpi: 0 (non-empty representation)
+mbedtls_debug_print_mpi:16:"00000000000000":"MyFile":999:"VALUE":"MyFile(0999)\: value of 'VALUE' (0 bits) is\:\nMyFile(0999)\:  00\n"
+
+Debug print mbedtls_mpi #2: 3 bits
+mbedtls_debug_print_mpi:16:"00000000000007":"MyFile":999:"VALUE":"MyFile(0999)\: value of 'VALUE' (3 bits) is\:\nMyFile(0999)\:  07\n"
+
+Debug print mbedtls_mpi: 49 bits
+mbedtls_debug_print_mpi:16:"01020304050607":"MyFile":999:"VALUE":"MyFile(0999)\: value of 'VALUE' (49 bits) is\:\nMyFile(0999)\:  01 02 03 04 05 06 07\n"
+
+Debug print mbedtls_mpi: 759 bits
+mbedtls_debug_print_mpi:16:"0000000000000000000000000000000000000000000000000000000041379d00fed1491fe15df284dfde4a142f68aa8d412023195cee66883e6290ffe703f4ea5963bf212713cee46b107c09182b5edcd955adac418bf4918e2889af48e1099d513830cec85c26ac1e158b52620e33ba8692f893efbb2f958b4424":"MyFile":999:"VALUE":"MyFile(0999)\: value of 'VALUE' (759 bits) is\:\nMyFile(0999)\:  41 37 9d 00 fe d1 49 1f e1 5d f2 84 df de 4a 14\nMyFile(0999)\:  2f 68 aa 8d 41 20 23 19 5c ee 66 88 3e 62 90 ff\nMyFile(0999)\:  e7 03 f4 ea 59 63 bf 21 27 13 ce e4 6b 10 7c 09\nMyFile(0999)\:  18 2b 5e dc d9 55 ad ac 41 8b f4 91 8e 28 89 af\nMyFile(0999)\:  48 e1 09 9d 51 38 30 ce c8 5c 26 ac 1e 15 8b 52\nMyFile(0999)\:  62 0e 33 ba 86 92 f8 93 ef bb 2f 95 8b 44 24\n"
+
+Debug print mbedtls_mpi: 764 bits #1
+mbedtls_debug_print_mpi:16:"0941379d00fed1491fe15df284dfde4a142f68aa8d412023195cee66883e6290ffe703f4ea5963bf212713cee46b107c09182b5edcd955adac418bf4918e2889af48e1099d513830cec85c26ac1e158b52620e33ba8692f893efbb2f958b4424":"MyFile":999:"VALUE":"MyFile(0999)\: value of 'VALUE' (764 bits) is\:\nMyFile(0999)\:  09 41 37 9d 00 fe d1 49 1f e1 5d f2 84 df de 4a\nMyFile(0999)\:  14 2f 68 aa 8d 41 20 23 19 5c ee 66 88 3e 62 90\nMyFile(0999)\:  ff e7 03 f4 ea 59 63 bf 21 27 13 ce e4 6b 10 7c\nMyFile(0999)\:  09 18 2b 5e dc d9 55 ad ac 41 8b f4 91 8e 28 89\nMyFile(0999)\:  af 48 e1 09 9d 51 38 30 ce c8 5c 26 ac 1e 15 8b\nMyFile(0999)\:  52 62 0e 33 ba 86 92 f8 93 ef bb 2f 95 8b 44 24\n"
+
+Debug print mbedtls_mpi: 764 bits #2
+mbedtls_debug_print_mpi:16:"0000000000000000000000000000000000000000000000000000000941379d00fed1491fe15df284dfde4a142f68aa8d412023195cee66883e6290ffe703f4ea5963bf212713cee46b107c09182b5edcd955adac418bf4918e2889af48e1099d513830cec85c26ac1e158b52620e33ba8692f893efbb2f958b4424":"MyFile":999:"VALUE":"MyFile(0999)\: value of 'VALUE' (764 bits) is\:\nMyFile(0999)\:  09 41 37 9d 00 fe d1 49 1f e1 5d f2 84 df de 4a\nMyFile(0999)\:  14 2f 68 aa 8d 41 20 23 19 5c ee 66 88 3e 62 90\nMyFile(0999)\:  ff e7 03 f4 ea 59 63 bf 21 27 13 ce e4 6b 10 7c\nMyFile(0999)\:  09 18 2b 5e dc d9 55 ad ac 41 8b f4 91 8e 28 89\nMyFile(0999)\:  af 48 e1 09 9d 51 38 30 ce c8 5c 26 ac 1e 15 8b\nMyFile(0999)\:  52 62 0e 33 ba 86 92 f8 93 ef bb 2f 95 8b 44 24\n"
+
 Debug print certificate #1 (RSA)
 depends_on:MBEDTLS_PEM_PARSE_C:MBEDTLS_BASE64_C:MBEDTLS_RSA_C:MBEDTLS_SHA1_C:!MBEDTLS_X509_REMOVE_INFO
 mbedtls_debug_print_crt:"data_files/server1.crt":"MyFile":999:"PREFIX_":"MyFile(0999)\: PREFIX_ #1\:\nMyFile(0999)\: cert. version     \: 3\nMyFile(0999)\: serial number     \: 01\nMyFile(0999)\: issuer name       \: C=NL, O=PolarSSL, CN=PolarSSL Test CA\nMyFile(0999)\: subject name      \: C=NL, O=PolarSSL, CN=PolarSSL Server 1\nMyFile(0999)\: issued  on        \: 2019-02-10 14\:44\:06\nMyFile(0999)\: expires on        \: 2029-02-10 14\:44\:06\nMyFile(0999)\: signed using      \: RSA with SHA1\nMyFile(0999)\: RSA key size      \: 2048 bits\nMyFile(0999)\: basic constraints \: CA=false\nMyFile(0999)\: value of 'crt->rsa.N' (2048 bits) is\:\nMyFile(0999)\:  a9 02 1f 3d 40 6a d5 55 53 8b fd 36 ee 82 65 2e\nMyFile(0999)\:  15 61 5e 89 bf b8 e8 45 90 db ee 88 16 52 d3 f1\nMyFile(0999)\:  43 50 47 96 12 59 64 87 6b fd 2b e0 46 f9 73 be\nMyFile(0999)\:  dd cf 92 e1 91 5b ed 66 a0 6f 89 29 79 45 80 d0\nMyFile(0999)\:  83 6a d5 41 43 77 5f 39 7c 09 04 47 82 b0 57 39\nMyFile(0999)\:  70 ed a3 ec 15 19 1e a8 33 08 47 c1 05 42 a9 fd\nMyFile(0999)\:  4c c3 b4 df dd 06 1f 4d 10 51 40 67 73 13 0f 40\nMyFile(0999)\:  f8 6d 81 25 5f 0a b1 53 c6 30 7e 15 39 ac f9 5a\nMyFile(0999)\:  ee 7f 92 9e a6 05 5b e7 13 97 85 b5 23 92 d9 d4\nMyFile(0999)\:  24 06 d5 09 25 89 75 07 dd a6 1a 8f 3f 09 19 be\nMyFile(0999)\:  ad 65 2c 64 eb 95 9b dc fe 41 5e 17 a6 da 6c 5b\nMyFile(0999)\:  69 cc 02 ba 14 2c 16 24 9c 4a dc cd d0 f7 52 67\nMyFile(0999)\:  73 f1 2d a0 23 fd 7e f4 31 ca 2d 70 ca 89 0b 04\nMyFile(0999)\:  db 2e a6 4f 70 6e 9e ce bd 58 89 e2 53 59 9e 6e\nMyFile(0999)\:  5a 92 65 e2 88 3f 0c 94 19 a3 dd e5 e8 9d 95 13\nMyFile(0999)\:  ed 29 db ab 70 12 dc 5a ca 6b 17 ab 52 82 54 b1\nMyFile(0999)\: value of 'crt->rsa.E' (17 bits) is\:\nMyFile(0999)\:  01 00 01\n"
@@ -44,21 +65,3 @@
 Debug print certificate #2 (EC)
 depends_on:MBEDTLS_PEM_PARSE_C:MBEDTLS_BASE64_C:MBEDTLS_ECDSA_C:MBEDTLS_ECP_C:MBEDTLS_ECP_DP_SECP384R1_ENABLED:MBEDTLS_SHA256_C:!MBEDTLS_X509_REMOVE_INFO
 mbedtls_debug_print_crt:"data_files/test-ca2.crt":"MyFile":999:"PREFIX_":"MyFile(0999)\: PREFIX_ #1\:\nMyFile(0999)\: cert. version     \: 3\nMyFile(0999)\: serial number     \: C1\:43\:E2\:7E\:62\:43\:CC\:E8\nMyFile(0999)\: issuer name       \: C=NL, O=PolarSSL, CN=Polarssl Test EC CA\nMyFile(0999)\: subject name      \: C=NL, O=PolarSSL, CN=Polarssl Test EC CA\nMyFile(0999)\: issued  on        \: 2019-02-10 14\:44\:00\nMyFile(0999)\: expires on        \: 2029-02-10 14\:44\:00\nMyFile(0999)\: signed using      \: ECDSA with SHA256\nMyFile(0999)\: EC key size       \: 384 bits\nMyFile(0999)\: basic constraints \: CA=true\nMyFile(0999)\: value of 'crt->eckey.Q(X)' (384 bits) is\:\nMyFile(0999)\:  c3 da 2b 34 41 37 58 2f 87 56 fe fc 89 ba 29 43\nMyFile(0999)\:  4b 4e e0 6e c3 0e 57 53 33 39 58 d4 52 b4 91 95\nMyFile(0999)\:  39 0b 23 df 5f 17 24 62 48 fc 1a 95 29 ce 2c 2d\nMyFile(0999)\: value of 'crt->eckey.Q(Y)' (384 bits) is\:\nMyFile(0999)\:  87 c2 88 52 80 af d6 6a ab 21 dd b8 d3 1c 6e 58\nMyFile(0999)\:  b8 ca e8 b2 69 8e f3 41 ad 29 c3 b4 5f 75 a7 47\nMyFile(0999)\:  6f d5 19 29 55 69 9a 53 3b 20 b4 66 16 60 33 1e\n"
-
-Debug print mbedtls_mpi #1
-mbedtls_debug_print_mpi:16:"01020304050607":"MyFile":999:"VALUE":"MyFile(0999)\: value of 'VALUE' (49 bits) is\:\nMyFile(0999)\:  01 02 03 04 05 06 07\n"
-
-Debug print mbedtls_mpi #2
-mbedtls_debug_print_mpi:16:"00000000000007":"MyFile":999:"VALUE":"MyFile(0999)\: value of 'VALUE' (3 bits) is\:\nMyFile(0999)\:  07\n"
-
-Debug print mbedtls_mpi #3
-mbedtls_debug_print_mpi:16:"00000000000000":"MyFile":999:"VALUE":"MyFile(0999)\: value of 'VALUE' (0 bits) is\:\nMyFile(0999)\:  00\n"
-
-Debug print mbedtls_mpi #4
-mbedtls_debug_print_mpi:16:"0941379d00fed1491fe15df284dfde4a142f68aa8d412023195cee66883e6290ffe703f4ea5963bf212713cee46b107c09182b5edcd955adac418bf4918e2889af48e1099d513830cec85c26ac1e158b52620e33ba8692f893efbb2f958b4424":"MyFile":999:"VALUE":"MyFile(0999)\: value of 'VALUE' (764 bits) is\:\nMyFile(0999)\:  09 41 37 9d 00 fe d1 49 1f e1 5d f2 84 df de 4a\nMyFile(0999)\:  14 2f 68 aa 8d 41 20 23 19 5c ee 66 88 3e 62 90\nMyFile(0999)\:  ff e7 03 f4 ea 59 63 bf 21 27 13 ce e4 6b 10 7c\nMyFile(0999)\:  09 18 2b 5e dc d9 55 ad ac 41 8b f4 91 8e 28 89\nMyFile(0999)\:  af 48 e1 09 9d 51 38 30 ce c8 5c 26 ac 1e 15 8b\nMyFile(0999)\:  52 62 0e 33 ba 86 92 f8 93 ef bb 2f 95 8b 44 24\n"
-
-Debug print mbedtls_mpi #5
-mbedtls_debug_print_mpi:16:"0000000000000000000000000000000000000000000000000000000941379d00fed1491fe15df284dfde4a142f68aa8d412023195cee66883e6290ffe703f4ea5963bf212713cee46b107c09182b5edcd955adac418bf4918e2889af48e1099d513830cec85c26ac1e158b52620e33ba8692f893efbb2f958b4424":"MyFile":999:"VALUE":"MyFile(0999)\: value of 'VALUE' (764 bits) is\:\nMyFile(0999)\:  09 41 37 9d 00 fe d1 49 1f e1 5d f2 84 df de 4a\nMyFile(0999)\:  14 2f 68 aa 8d 41 20 23 19 5c ee 66 88 3e 62 90\nMyFile(0999)\:  ff e7 03 f4 ea 59 63 bf 21 27 13 ce e4 6b 10 7c\nMyFile(0999)\:  09 18 2b 5e dc d9 55 ad ac 41 8b f4 91 8e 28 89\nMyFile(0999)\:  af 48 e1 09 9d 51 38 30 ce c8 5c 26 ac 1e 15 8b\nMyFile(0999)\:  52 62 0e 33 ba 86 92 f8 93 ef bb 2f 95 8b 44 24\n"
-
-Debug print mbedtls_mpi #6
-mbedtls_debug_print_mpi:16:"0000000000000000000000000000000000000000000000000000000041379d00fed1491fe15df284dfde4a142f68aa8d412023195cee66883e6290ffe703f4ea5963bf212713cee46b107c09182b5edcd955adac418bf4918e2889af48e1099d513830cec85c26ac1e158b52620e33ba8692f893efbb2f958b4424":"MyFile":999:"VALUE":"MyFile(0999)\: value of 'VALUE' (759 bits) is\:\nMyFile(0999)\:  41 37 9d 00 fe d1 49 1f e1 5d f2 84 df de 4a 14\nMyFile(0999)\:  2f 68 aa 8d 41 20 23 19 5c ee 66 88 3e 62 90 ff\nMyFile(0999)\:  e7 03 f4 ea 59 63 bf 21 27 13 ce e4 6b 10 7c 09\nMyFile(0999)\:  18 2b 5e dc d9 55 ad ac 41 8b f4 91 8e 28 89 af\nMyFile(0999)\:  48 e1 09 9d 51 38 30 ce c8 5c 26 ac 1e 15 8b 52\nMyFile(0999)\:  62 0e 33 ba 86 92 f8 93 ef bb 2f 95 8b 44 24\n"
diff --git a/tests/suites/test_suite_debug.function b/tests/suites/test_suite_debug.function
index ad50e53..fda6939 100644
--- a/tests/suites/test_suite_debug.function
+++ b/tests/suites/test_suite_debug.function
@@ -179,7 +179,9 @@
 
     TEST_ASSERT( mbedtls_ssl_setup( &ssl, &conf ) == 0 );
 
-    TEST_ASSERT( mbedtls_mpi_read_string( &val, radix, value ) == 0 );
+    /* If value is empty, keep val->n == 0. */
+    if( value[0] != 0 )
+        TEST_ASSERT( mbedtls_mpi_read_string( &val, radix, value ) == 0 );
 
     mbedtls_ssl_conf_dbg( &conf, string_debug, &buffer);