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 );