diff --git a/ChangeLog b/ChangeLog
index 51ca066..aa872a3 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -70,6 +70,8 @@
    * Extend cert_write example program by options to set the CRT version
      and the message digest. Further, allow enabling/disabling of authority
      identifier, subject identifier and basic constraints extensions.
+   * Add explicit warnings for the use of MD2, MD4, MD5, SHA-1, DES and ARC4
+     throughout the library.
 
 = mbed TLS 2.1.9 branch released 2017-08-10
 
diff --git a/include/mbedtls/arc4.h b/include/mbedtls/arc4.h
index 5fc5395..08ffd20 100644
--- a/include/mbedtls/arc4.h
+++ b/include/mbedtls/arc4.h
@@ -19,6 +19,10 @@
  *  limitations under the License.
  *
  *  This file is part of mbed TLS (https://tls.mbed.org)
+ *
+ * \warning   ARC4 is considered a weak cipher and its use constitutes a
+ *            security risk. We recommend considering stronger ciphers instead.
+ *
  */
 #ifndef MBEDTLS_ARC4_H
 #define MBEDTLS_ARC4_H
@@ -40,7 +44,11 @@
 #endif
 
 /**
- * \brief          ARC4 context structure
+ * \brief     ARC4 context structure
+ *
+ * \warning   ARC4 is considered a weak cipher and its use constitutes a
+ *            security risk. We recommend considering stronger ciphers instead.
+ *
  */
 typedef struct
 {
@@ -54,6 +62,11 @@
  * \brief          Initialize ARC4 context
  *
  * \param ctx      ARC4 context to be initialized
+ *
+ * \warning        ARC4 is considered a weak cipher and its use constitutes a
+ *                 security risk. We recommend considering stronger ciphers
+ *                 instead.
+ *
  */
 void mbedtls_arc4_init( mbedtls_arc4_context *ctx );
 
@@ -61,6 +74,11 @@
  * \brief          Clear ARC4 context
  *
  * \param ctx      ARC4 context to be cleared
+ *
+ * \warning        ARC4 is considered a weak cipher and its use constitutes a
+ *                 security risk. We recommend considering stronger ciphers
+ *                 instead.
+ *
  */
 void mbedtls_arc4_free( mbedtls_arc4_context *ctx );
 
@@ -70,6 +88,11 @@
  * \param ctx      ARC4 context to be setup
  * \param key      the secret key
  * \param keylen   length of the key, in bytes
+ *
+ * \warning        ARC4 is considered a weak cipher and its use constitutes a
+ *                 security risk. We recommend considering stronger ciphers
+ *                 instead.
+ *
  */
 void mbedtls_arc4_setup( mbedtls_arc4_context *ctx, const unsigned char *key,
                  unsigned int keylen );
@@ -83,6 +106,11 @@
  * \param output   buffer for the output data
  *
  * \return         0 if successful
+ *
+ * \warning        ARC4 is considered a weak cipher and its use constitutes a
+ *                 security risk. We recommend considering stronger ciphers
+ *                 instead.
+ *
  */
 int mbedtls_arc4_crypt( mbedtls_arc4_context *ctx, size_t length, const unsigned char *input,
                 unsigned char *output );
@@ -103,6 +131,11 @@
  * \brief          Checkup routine
  *
  * \return         0 if successful, or 1 if the test failed
+ *
+ * \warning        ARC4 is considered a weak cipher and its use constitutes a
+ *                 security risk. We recommend considering stronger ciphers
+ *                 instead.
+ *
  */
 int mbedtls_arc4_self_test( int verbose );
 
diff --git a/include/mbedtls/cipher.h b/include/mbedtls/cipher.h
index 70000f5..464c4ad 100644
--- a/include/mbedtls/cipher.h
+++ b/include/mbedtls/cipher.h
@@ -65,6 +65,13 @@
 extern "C" {
 #endif
 
+/**
+ * \brief     Enumeration of supported ciphers
+ *
+ * \warning   ARC4 and DES are considered weak ciphers and their use
+ *            constitutes a security risk. We recommend considering stronger
+ *            ciphers instead.
+ */
 typedef enum {
     MBEDTLS_CIPHER_ID_NONE = 0,
     MBEDTLS_CIPHER_ID_NULL,
@@ -76,6 +83,13 @@
     MBEDTLS_CIPHER_ID_ARC4,
 } mbedtls_cipher_id_t;
 
+/**
+ * \brief     Enumeration of supported (cipher,mode) pairs
+ *
+ * \warning   ARC4 and DES are considered weak ciphers and their use
+ *            constitutes a security risk. We recommend considering stronger
+ *            ciphers instead.
+ */
 typedef enum {
     MBEDTLS_CIPHER_NONE = 0,
     MBEDTLS_CIPHER_NULL,
diff --git a/include/mbedtls/config.h b/include/mbedtls/config.h
index 0c51fea..00589dd 100644
--- a/include/mbedtls/config.h
+++ b/include/mbedtls/config.h
@@ -224,6 +224,12 @@
  *
  * Uncomment a macro to enable alternate implementation of the corresponding
  * module.
+ *
+ * \warning   MD2, MD4, MD5, ARC4, DES and SHA-1 are considered weak and their
+ *            use constitutes a security risk. If possible, we recommend
+ *            avoiding dependencies on them, and considering stronger message
+ *            digests and ciphers instead.
+ *
  */
 //#define MBEDTLS_AES_ALT
 //#define MBEDTLS_ARC4_ALT
@@ -261,6 +267,12 @@
  *
  * Uncomment a macro to enable alternate implementation of the corresponding
  * function.
+ *
+ * \warning   MD2, MD4, MD5, DES and SHA-1 are considered weak and their use
+ *            constitutes a security risk. If possible, we recommend avoiding
+ *            dependencies on them, and considering stronger message digests
+ *            and ciphers instead.
+ *
  */
 //#define MBEDTLS_MD2_PROCESS_ALT
 //#define MBEDTLS_MD4_PROCESS_ALT
@@ -390,6 +402,9 @@
  *      MBEDTLS_TLS_DHE_RSA_WITH_DES_CBC_SHA
  *
  * Uncomment this macro to enable weak ciphersuites
+ *
+ * \warning   DES is considered a weak cipher and its use constitutes a
+ *            security risk. We recommend considering stronger ciphers instead.
  */
 //#define MBEDTLS_ENABLE_WEAK_CIPHERSUITES
 
@@ -1416,6 +1431,11 @@
  *      MBEDTLS_TLS_RSA_WITH_RC4_128_MD5
  *      MBEDTLS_TLS_RSA_PSK_WITH_RC4_128_SHA
  *      MBEDTLS_TLS_PSK_WITH_RC4_128_SHA
+ *
+ * \warning   ARC4 is considered a weak cipher and its use constitutes a
+ *            security risk. If possible, we recommend avoidng dependencies on
+ *            it, and considering stronger ciphers instead.
+ *
  */
 #define MBEDTLS_ARC4_C
 
@@ -1628,6 +1648,9 @@
  *      MBEDTLS_TLS_PSK_WITH_3DES_EDE_CBC_SHA
  *
  * PEM_PARSE uses DES/3DES for decrypting encrypted keys.
+ *
+ * \warning   DES is considered a weak cipher and its use constitutes a
+ *            security risk. We recommend considering stronger ciphers instead.
  */
 #define MBEDTLS_DES_C
 
@@ -1787,6 +1810,11 @@
  * Caller:
  *
  * Uncomment to enable support for (rare) MD2-signed X.509 certs.
+ *
+ * \warning   MD2 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_MD2_C
 
@@ -1799,6 +1827,11 @@
  * Caller:
  *
  * Uncomment to enable support for (rare) MD4-signed X.509 certs.
+ *
+ * \warning   MD4 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_MD4_C
 
@@ -1812,8 +1845,15 @@
  *          library/pem.c
  *          library/ssl_tls.c
  *
- * This module is required for SSL/TLS and X.509.
- * PEM_PARSE uses MD5 for decrypting encrypted keys.
+ * This module is required for SSL/TLS up to version 1.1, and it can be used in
+ * TLS 1.2 through the choice on handshake parameters. Further, it is used for
+ * checking MD5-signed certificates, and for PBKDF1 when decrypting PEM-encoded
+ * encrypted keys.
+ *
+ * \warning   MD5 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_MD5_C
 
@@ -2067,6 +2107,11 @@
  *
  * This module is required for SSL/TLS up to version 1.1, for TLS 1.2
  * depending on the handshake parameters, and for SHA1-signed certificates.
+ *
+ * \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_SHA1_C
 
@@ -2431,8 +2476,13 @@
  * Allow SHA-1 in the default TLS configuration for certificate signing.
  * Without this build-time option, SHA-1 support must be activated explicitly
  * through mbedtls_ssl_conf_cert_profile. Turning on this option is not
- * recommended because of it is possible to generte SHA-1 collisions, however
+ * recommended because of it is possible to generate SHA-1 collisions, however
  * this may be safe for legacy infrastructure where additional controls apply.
+ *
+ * \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_CERTIFICATES
 
@@ -2443,7 +2493,13 @@
  * 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
- * for compatibility with existing peers.
+ * 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
 
diff --git a/include/mbedtls/des.h b/include/mbedtls/des.h
index 5ca2ecf..37032d3 100644
--- a/include/mbedtls/des.h
+++ b/include/mbedtls/des.h
@@ -19,6 +19,11 @@
  *  limitations under the License.
  *
  *  This file is part of mbed TLS (https://tls.mbed.org)
+ *
+ * \warning   DES is considered a weak cipher and its use constitutes a
+ *            security risk. We recommend considering stronger ciphers
+ *            instead.
+ *
  */
 #ifndef MBEDTLS_DES_H
 #define MBEDTLS_DES_H
@@ -49,6 +54,10 @@
 
 /**
  * \brief          DES context structure
+ *
+ * \warning        DES is considered a weak cipher and its use constitutes a
+ *                 security risk. We recommend considering stronger ciphers
+ *                 instead.
  */
 typedef struct
 {
@@ -69,6 +78,10 @@
  * \brief          Initialize DES context
  *
  * \param ctx      DES context to be initialized
+ *
+ * \warning        DES is considered a weak cipher and its use constitutes a
+ *                 security risk. We recommend considering stronger ciphers
+ *                 instead.
  */
 void mbedtls_des_init( mbedtls_des_context *ctx );
 
@@ -76,6 +89,10 @@
  * \brief          Clear DES context
  *
  * \param ctx      DES context to be cleared
+ *
+ * \warning        DES is considered a weak cipher and its use constitutes a
+ *                 security risk. We recommend considering stronger ciphers
+ *                 instead.
  */
 void mbedtls_des_free( mbedtls_des_context *ctx );
 
@@ -100,6 +117,10 @@
  *                 a parity bit to allow verification.
  *
  * \param key      8-byte secret key
+ *
+ * \warning        DES is considered a weak cipher and its use constitutes a
+ *                 security risk. We recommend considering stronger ciphers
+ *                 instead.
  */
 void mbedtls_des_key_set_parity( unsigned char key[MBEDTLS_DES_KEY_SIZE] );
 
@@ -112,6 +133,10 @@
  * \param key      8-byte secret key
  *
  * \return         0 is parity was ok, 1 if parity was not correct.
+ *
+ * \warning        DES is considered a weak cipher and its use constitutes a
+ *                 security risk. We recommend considering stronger ciphers
+ *                 instead.
  */
 int mbedtls_des_key_check_key_parity( const unsigned char key[MBEDTLS_DES_KEY_SIZE] );
 
@@ -121,6 +146,10 @@
  * \param key      8-byte secret key
  *
  * \return         0 if no weak key was found, 1 if a weak key was identified.
+ *
+ * \warning        DES is considered a weak cipher and its use constitutes a
+ *                 security risk. We recommend considering stronger ciphers
+ *                 instead.
  */
 int mbedtls_des_key_check_weak( const unsigned char key[MBEDTLS_DES_KEY_SIZE] );
 
@@ -131,6 +160,10 @@
  * \param key      8-byte secret key
  *
  * \return         0
+ *
+ * \warning        DES is considered a weak cipher and its use constitutes a
+ *                 security risk. We recommend considering stronger ciphers
+ *                 instead.
  */
 int mbedtls_des_setkey_enc( mbedtls_des_context *ctx, const unsigned char key[MBEDTLS_DES_KEY_SIZE] );
 
@@ -141,6 +174,10 @@
  * \param key      8-byte secret key
  *
  * \return         0
+ *
+ * \warning        DES is considered a weak cipher and its use constitutes a
+ *                 security risk. We recommend considering stronger ciphers
+ *                 instead.
  */
 int mbedtls_des_setkey_dec( mbedtls_des_context *ctx, const unsigned char key[MBEDTLS_DES_KEY_SIZE] );
 
@@ -196,6 +233,10 @@
  * \param output   64-bit output block
  *
  * \return         0 if successful
+ *
+ * \warning        DES is considered a weak cipher and its use constitutes a
+ *                 security risk. We recommend considering stronger ciphers
+ *                 instead.
  */
 int mbedtls_des_crypt_ecb( mbedtls_des_context *ctx,
                     const unsigned char input[8],
@@ -219,6 +260,10 @@
  * \param iv       initialization vector (updated after use)
  * \param input    buffer holding the input data
  * \param output   buffer holding the output data
+ *
+ * \warning        DES is considered a weak cipher and its use constitutes a
+ *                 security risk. We recommend considering stronger ciphers
+ *                 instead.
  */
 int mbedtls_des_crypt_cbc( mbedtls_des_context *ctx,
                     int mode,
@@ -277,6 +322,10 @@
  *
  * \param SK       Round keys
  * \param key      Base key
+ *
+ * \warning        DES is considered a weak cipher and its use constitutes a
+ *                 security risk. We recommend considering stronger ciphers
+ *                 instead.
  */
 void mbedtls_des_setkey( uint32_t SK[32],
                          const unsigned char key[MBEDTLS_DES_KEY_SIZE] );
diff --git a/include/mbedtls/md.h b/include/mbedtls/md.h
index 00b1e3a..b48877a 100644
--- a/include/mbedtls/md.h
+++ b/include/mbedtls/md.h
@@ -42,6 +42,14 @@
 extern "C" {
 #endif
 
+/**
+ * \brief     Enumeration of supported message digests
+ *
+ * \warning   MD2, MD4, MD5 and SHA-1 are considered weak message digests and
+ *            their use constitutes a security risk. We recommend considering
+ *            stronger message digests instead.
+ *
+ */
 typedef enum {
     MBEDTLS_MD_NONE=0,
     MBEDTLS_MD_MD2,
diff --git a/include/mbedtls/md2.h b/include/mbedtls/md2.h
index 0f93fbf..d516042 100644
--- a/include/mbedtls/md2.h
+++ b/include/mbedtls/md2.h
@@ -19,6 +19,11 @@
  *  limitations under the License.
  *
  *  This file is part of mbed TLS (https://tls.mbed.org)
+ *
+ * \warning   MD2 is considered a weak message digest and its use constitutes a
+ *            security risk. We recommend considering stronger message
+ *            digests instead.
+ *
  */
 #ifndef MBEDTLS_MD2_H
 #define MBEDTLS_MD2_H
@@ -41,6 +46,11 @@
 
 /**
  * \brief          MD2 context structure
+ *
+ * \warning        MD2 is considered a weak message digest and its use
+ *                 constitutes a security risk. We recommend considering
+ *                 stronger message digests instead.
+ *
  */
 typedef struct
 {
@@ -55,6 +65,11 @@
  * \brief          Initialize MD2 context
  *
  * \param ctx      MD2 context to be initialized
+ *
+ * \warning        MD2 is considered a weak message digest and its use
+ *                 constitutes a security risk. We recommend considering
+ *                 stronger message digests instead.
+ *
  */
 void mbedtls_md2_init( mbedtls_md2_context *ctx );
 
@@ -62,6 +77,11 @@
  * \brief          Clear MD2 context
  *
  * \param ctx      MD2 context to be cleared
+ *
+ * \warning        MD2 is considered a weak message digest and its use
+ *                 constitutes a security risk. We recommend considering
+ *                 stronger message digests instead.
+ *
  */
 void mbedtls_md2_free( mbedtls_md2_context *ctx );
 
@@ -70,6 +90,11 @@
  *
  * \param dst      The destination context
  * \param src      The context to be cloned
+ *
+ * \warning        MD2 is considered a weak message digest and its use
+ *                 constitutes a security risk. We recommend considering
+ *                 stronger message digests instead.
+ *
  */
 void mbedtls_md2_clone( mbedtls_md2_context *dst,
                         const mbedtls_md2_context *src );
@@ -78,6 +103,11 @@
  * \brief          MD2 context setup
  *
  * \param ctx      context to be initialized
+ *
+ * \warning        MD2 is considered a weak message digest and its use
+ *                 constitutes a security risk. We recommend considering
+ *                 stronger message digests instead.
+ *
  */
 void mbedtls_md2_starts( mbedtls_md2_context *ctx );
 
@@ -87,6 +117,11 @@
  * \param ctx      MD2 context
  * \param input    buffer holding the  data
  * \param ilen     length of the input data
+ *
+ * \warning        MD2 is considered a weak message digest and its use
+ *                 constitutes a security risk. We recommend considering
+ *                 stronger message digests instead.
+ *
  */
 void mbedtls_md2_update( mbedtls_md2_context *ctx, const unsigned char *input, size_t ilen );
 
@@ -95,6 +130,11 @@
  *
  * \param ctx      MD2 context
  * \param output   MD2 checksum result
+ *
+ * \warning        MD2 is considered a weak message digest and its use
+ *                 constitutes a security risk. We recommend considering
+ *                 stronger message digests instead.
+ *
  */
 void mbedtls_md2_finish( mbedtls_md2_context *ctx, unsigned char output[16] );
 
@@ -116,6 +156,11 @@
  * \param input    buffer holding the  data
  * \param ilen     length of the input data
  * \param output   MD2 checksum result
+ *
+ * \warning        MD2 is considered a weak message digest and its use
+ *                 constitutes a security risk. We recommend considering
+ *                 stronger message digests instead.
+ *
  */
 void mbedtls_md2( const unsigned char *input, size_t ilen, unsigned char output[16] );
 
@@ -123,6 +168,11 @@
  * \brief          Checkup routine
  *
  * \return         0 if successful, or 1 if the test failed
+ *
+ * \warning        MD2 is considered a weak message digest and its use
+ *                 constitutes a security risk. We recommend considering
+ *                 stronger message digests instead.
+ *
  */
 int mbedtls_md2_self_test( int verbose );
 
diff --git a/include/mbedtls/md4.h b/include/mbedtls/md4.h
index 45214d4..b02d4b6 100644
--- a/include/mbedtls/md4.h
+++ b/include/mbedtls/md4.h
@@ -19,6 +19,11 @@
  *  limitations under the License.
  *
  *  This file is part of mbed TLS (https://tls.mbed.org)
+ *
+ * \warning   MD4 is considered a weak message digest and its use constitutes a
+ *            security risk. We recommend considering stronger message
+ *            digests instead.
+ *
  */
 #ifndef MBEDTLS_MD4_H
 #define MBEDTLS_MD4_H
@@ -42,6 +47,11 @@
 
 /**
  * \brief          MD4 context structure
+ *
+ * \warning        MD4 is considered a weak message digest and its use
+ *                 constitutes a security risk. We recommend considering
+ *                 stronger message digests instead.
+ *
  */
 typedef struct
 {
@@ -55,6 +65,11 @@
  * \brief          Initialize MD4 context
  *
  * \param ctx      MD4 context to be initialized
+ *
+ * \warning        MD4 is considered a weak message digest and its use
+ *                 constitutes a security risk. We recommend considering
+ *                 stronger message digests instead.
+ *
  */
 void mbedtls_md4_init( mbedtls_md4_context *ctx );
 
@@ -62,6 +77,11 @@
  * \brief          Clear MD4 context
  *
  * \param ctx      MD4 context to be cleared
+ *
+ * \warning        MD4 is considered a weak message digest and its use
+ *                 constitutes a security risk. We recommend considering
+ *                 stronger message digests instead.
+ *
  */
 void mbedtls_md4_free( mbedtls_md4_context *ctx );
 
@@ -70,6 +90,11 @@
  *
  * \param dst      The destination context
  * \param src      The context to be cloned
+ *
+ * \warning        MD4 is considered a weak message digest and its use
+ *                 constitutes a security risk. We recommend considering
+ *                 stronger message digests instead.
+ *
  */
 void mbedtls_md4_clone( mbedtls_md4_context *dst,
                         const mbedtls_md4_context *src );
@@ -78,6 +103,10 @@
  * \brief          MD4 context setup
  *
  * \param ctx      context to be initialized
+ *
+ * \warning        MD4 is considered a weak message digest and its use
+ *                 constitutes a security risk. We recommend considering
+ *                 stronger message digests instead.
  */
 void mbedtls_md4_starts( mbedtls_md4_context *ctx );
 
@@ -87,6 +116,11 @@
  * \param ctx      MD4 context
  * \param input    buffer holding the  data
  * \param ilen     length of the input data
+ *
+ * \warning        MD4 is considered a weak message digest and its use
+ *                 constitutes a security risk. We recommend considering
+ *                 stronger message digests instead.
+ *
  */
 void mbedtls_md4_update( mbedtls_md4_context *ctx, const unsigned char *input, size_t ilen );
 
@@ -95,6 +129,11 @@
  *
  * \param ctx      MD4 context
  * \param output   MD4 checksum result
+ *
+ * \warning        MD4 is considered a weak message digest and its use
+ *                 constitutes a security risk. We recommend considering
+ *                 stronger message digests instead.
+ *
  */
 void mbedtls_md4_finish( mbedtls_md4_context *ctx, unsigned char output[16] );
 
@@ -116,6 +155,11 @@
  * \param input    buffer holding the  data
  * \param ilen     length of the input data
  * \param output   MD4 checksum result
+ *
+ * \warning        MD4 is considered a weak message digest and its use
+ *                 constitutes a security risk. We recommend considering
+ *                 stronger message digests instead.
+ *
  */
 void mbedtls_md4( const unsigned char *input, size_t ilen, unsigned char output[16] );
 
@@ -123,6 +167,11 @@
  * \brief          Checkup routine
  *
  * \return         0 if successful, or 1 if the test failed
+ *
+ * \warning        MD4 is considered a weak message digest and its use
+ *                 constitutes a security risk. We recommend considering
+ *                 stronger message digests instead.
+ *
  */
 int mbedtls_md4_self_test( int verbose );
 
diff --git a/include/mbedtls/md5.h b/include/mbedtls/md5.h
index 5a64061..1e67343 100644
--- a/include/mbedtls/md5.h
+++ b/include/mbedtls/md5.h
@@ -19,6 +19,11 @@
  *  limitations under the License.
  *
  *  This file is part of mbed TLS (https://tls.mbed.org)
+ *
+ * \warning   MD5 is considered a weak message digest and its use constitutes a
+ *            security risk. We recommend considering stronger message
+ *            digests instead.
+ *
  */
 #ifndef MBEDTLS_MD5_H
 #define MBEDTLS_MD5_H
@@ -42,6 +47,11 @@
 
 /**
  * \brief          MD5 context structure
+ *
+ * \warning        MD5 is considered a weak message digest and its use
+ *                 constitutes a security risk. We recommend considering
+ *                 stronger message digests instead.
+ *
  */
 typedef struct
 {
@@ -55,6 +65,11 @@
  * \brief          Initialize MD5 context
  *
  * \param ctx      MD5 context to be initialized
+ *
+ * \warning        MD5 is considered a weak message digest and its use
+ *                 constitutes a security risk. We recommend considering
+ *                 stronger message digests instead.
+ *
  */
 void mbedtls_md5_init( mbedtls_md5_context *ctx );
 
@@ -62,6 +77,11 @@
  * \brief          Clear MD5 context
  *
  * \param ctx      MD5 context to be cleared
+ *
+ * \warning        MD5 is considered a weak message digest and its use
+ *                 constitutes a security risk. We recommend considering
+ *                 stronger message digests instead.
+ *
  */
 void mbedtls_md5_free( mbedtls_md5_context *ctx );
 
@@ -70,6 +90,11 @@
  *
  * \param dst      The destination context
  * \param src      The context to be cloned
+ *
+ * \warning        MD5 is considered a weak message digest and its use
+ *                 constitutes a security risk. We recommend considering
+ *                 stronger message digests instead.
+ *
  */
 void mbedtls_md5_clone( mbedtls_md5_context *dst,
                         const mbedtls_md5_context *src );
@@ -78,6 +103,11 @@
  * \brief          MD5 context setup
  *
  * \param ctx      context to be initialized
+ *
+ * \warning        MD5 is considered a weak message digest and its use
+ *                 constitutes a security risk. We recommend considering
+ *                 stronger message digests instead.
+ *
  */
 void mbedtls_md5_starts( mbedtls_md5_context *ctx );
 
@@ -87,6 +117,11 @@
  * \param ctx      MD5 context
  * \param input    buffer holding the  data
  * \param ilen     length of the input data
+ *
+ * \warning        MD5 is considered a weak message digest and its use
+ *                 constitutes a security risk. We recommend considering
+ *                 stronger message digests instead.
+ *
  */
 void mbedtls_md5_update( mbedtls_md5_context *ctx, const unsigned char *input, size_t ilen );
 
@@ -95,6 +130,11 @@
  *
  * \param ctx      MD5 context
  * \param output   MD5 checksum result
+ *
+ * \warning        MD5 is considered a weak message digest and its use
+ *                 constitutes a security risk. We recommend considering
+ *                 stronger message digests instead.
+ *
  */
 void mbedtls_md5_finish( mbedtls_md5_context *ctx, unsigned char output[16] );
 
@@ -119,6 +159,11 @@
  * \param input    buffer holding the  data
  * \param ilen     length of the input data
  * \param output   MD5 checksum result
+ *
+ * \warning        MD5 is considered a weak message digest and its use
+ *                 constitutes a security risk. We recommend considering
+ *                 stronger message digests instead.
+ *
  */
 void mbedtls_md5( const unsigned char *input, size_t ilen, unsigned char output[16] );
 
@@ -126,6 +171,11 @@
  * \brief          Checkup routine
  *
  * \return         0 if successful, or 1 if the test failed
+ *
+ * \warning        MD5 is considered a weak message digest and its use
+ *                 constitutes a security risk. We recommend considering
+ *                 stronger message digests instead.
+ *
  */
 int mbedtls_md5_self_test( int verbose );
 
diff --git a/include/mbedtls/sha1.h b/include/mbedtls/sha1.h
index 7a67c6c..05c5d24 100644
--- a/include/mbedtls/sha1.h
+++ b/include/mbedtls/sha1.h
@@ -19,6 +19,11 @@
  *  limitations under the License.
  *
  *  This file is part of mbed TLS (https://tls.mbed.org)
+ *
+ * \warning   SHA-1 is considered a weak message digest and its use constitutes
+ *            a security risk. We recommend considering stronger message
+ *            digests instead.
+ *
  */
 #ifndef MBEDTLS_SHA1_H
 #define MBEDTLS_SHA1_H
@@ -42,6 +47,11 @@
 
 /**
  * \brief          SHA-1 context structure
+ *
+ * \warning        SHA-1 is considered a weak message digest and its use
+ *                 constitutes a security risk. We recommend considering
+ *                 stronger message digests instead.
+ *
  */
 typedef struct
 {
@@ -55,6 +65,11 @@
  * \brief          Initialize SHA-1 context
  *
  * \param ctx      SHA-1 context to be initialized
+ *
+ * \warning        SHA-1 is considered a weak message digest and its use
+ *                 constitutes a security risk. We recommend considering
+ *                 stronger message digests instead.
+ *
  */
 void mbedtls_sha1_init( mbedtls_sha1_context *ctx );
 
@@ -62,6 +77,11 @@
  * \brief          Clear SHA-1 context
  *
  * \param ctx      SHA-1 context to be cleared
+ *
+ * \warning        SHA-1 is considered a weak message digest and its use
+ *                 constitutes a security risk. We recommend considering
+ *                 stronger message digests instead.
+ *
  */
 void mbedtls_sha1_free( mbedtls_sha1_context *ctx );
 
@@ -70,6 +90,11 @@
  *
  * \param dst      The destination context
  * \param src      The context to be cloned
+ *
+ * \warning        SHA-1 is considered a weak message digest and its use
+ *                 constitutes a security risk. We recommend considering
+ *                 stronger message digests instead.
+ *
  */
 void mbedtls_sha1_clone( mbedtls_sha1_context *dst,
                          const mbedtls_sha1_context *src );
@@ -78,6 +103,11 @@
  * \brief          SHA-1 context setup
  *
  * \param ctx      context to be initialized
+ *
+ * \warning        SHA-1 is considered a weak message digest and its use
+ *                 constitutes a security risk. We recommend considering
+ *                 stronger message digests instead.
+ *
  */
 void mbedtls_sha1_starts( mbedtls_sha1_context *ctx );
 
@@ -87,6 +117,11 @@
  * \param ctx      SHA-1 context
  * \param input    buffer holding the  data
  * \param ilen     length of the input data
+ *
+ * \warning        SHA-1 is considered a weak message digest and its use
+ *                 constitutes a security risk. We recommend considering
+ *                 stronger message digests instead.
+ *
  */
 void mbedtls_sha1_update( mbedtls_sha1_context *ctx, const unsigned char *input, size_t ilen );
 
@@ -95,6 +130,11 @@
  *
  * \param ctx      SHA-1 context
  * \param output   SHA-1 checksum result
+ *
+ * \warning        SHA-1 is considered a weak message digest and its use
+ *                 constitutes a security risk. We recommend considering
+ *                 stronger message digests instead.
+ *
  */
 void mbedtls_sha1_finish( mbedtls_sha1_context *ctx, unsigned char output[20] );
 
@@ -119,6 +159,11 @@
  * \param input    buffer holding the  data
  * \param ilen     length of the input data
  * \param output   SHA-1 checksum result
+ *
+ * \warning        SHA-1 is considered a weak message digest and its use
+ *                 constitutes a security risk. We recommend considering
+ *                 stronger message digests instead.
+ *
  */
 void mbedtls_sha1( const unsigned char *input, size_t ilen, unsigned char output[20] );
 
@@ -126,6 +171,11 @@
  * \brief          Checkup routine
  *
  * \return         0 if successful, or 1 if the test failed
+ *
+ * \warning        SHA-1 is considered a weak message digest and its use
+ *                 constitutes a security risk. We recommend considering
+ *                 stronger message digests instead.
+ *
  */
 int mbedtls_sha1_self_test( int verbose );