diff --git a/include/mbedtls/ssl.h b/include/mbedtls/ssl.h
index b2d5574..89912c6 100644
--- a/include/mbedtls/ssl.h
+++ b/include/mbedtls/ssl.h
@@ -628,9 +628,15 @@
 #endif
 
 /* TODO: Document */
-typedef int mbedtls_ssl_cache_get_t( void *data, mbedtls_ssl_session *session );
+typedef int mbedtls_ssl_cache_get_t( void *data,
+                                     unsigned char const *session_id,
+                                     size_t session_id_len,
+                                     mbedtls_ssl_session *session );
 /* TODO: Document */
-typedef int mbedtls_ssl_cache_set_t( void *data, const mbedtls_ssl_session *session );
+typedef int mbedtls_ssl_cache_set_t( void *data,
+                                     unsigned char const *session_id,
+                                     size_t session_id_len,
+                                     const mbedtls_ssl_session *session );
 
 #if defined(MBEDTLS_SSL_ASYNC_PRIVATE)
 #if defined(MBEDTLS_X509_CRT_PARSE_C)
diff --git a/include/mbedtls/ssl_cache.h b/include/mbedtls/ssl_cache.h
index c6ef296..cb55f7f 100644
--- a/include/mbedtls/ssl_cache.h
+++ b/include/mbedtls/ssl_cache.h
@@ -99,19 +99,32 @@
  * \brief          Cache get callback implementation
  *                 (Thread-safe if MBEDTLS_THREADING_C is enabled)
  *
- * \param data     SSL cache context
- * \param session  session to retrieve entry for
+ * \param data            The SSL cache context to use.
+ * \param session_id      The pointer to the buffer holding the session ID
+ *                        for the session to load.
+ * \param session_id_len  The length of \p session_id in bytes.
+ * \param session         The address at which to store the session
+ *                        associated with \p session_id, if present.
  */
-int mbedtls_ssl_cache_get( void *data, mbedtls_ssl_session *session );
+int mbedtls_ssl_cache_get( void *data,
+                           unsigned char const *session_id,
+                           size_t session_id_len,
+                           mbedtls_ssl_session *session );
 
 /**
  * \brief          Cache set callback implementation
  *                 (Thread-safe if MBEDTLS_THREADING_C is enabled)
  *
- * \param data     SSL cache context
- * \param session  session to store entry for
+ * \param data            The SSL cache context to use.
+ * \param session_id      The pointer to the buffer holding the session ID
+ *                        associated to \p session.
+ * \param session_id_len  The length of \p session_id in bytes.
+ * \param session         The session to store.
  */
-int mbedtls_ssl_cache_set( void *data, const mbedtls_ssl_session *session );
+int mbedtls_ssl_cache_set( void *data,
+                           unsigned char const *session_id,
+                           size_t session_id_len,
+                           const mbedtls_ssl_session *session );
 
 #if defined(MBEDTLS_HAVE_TIME)
 /**
diff --git a/library/ssl_cache.c b/library/ssl_cache.c
index ce85157..e0e2177 100644
--- a/library/ssl_cache.c
+++ b/library/ssl_cache.c
@@ -50,7 +50,10 @@
 #endif
 }
 
-int mbedtls_ssl_cache_get( void *data, mbedtls_ssl_session *session )
+int mbedtls_ssl_cache_get( void *data,
+                           unsigned char const *session_id,
+                           size_t session_id_len,
+                           mbedtls_ssl_session *session )
 {
     int ret = 1;
 #if defined(MBEDTLS_HAVE_TIME)
@@ -78,8 +81,8 @@
             continue;
 #endif
 
-        if( session->id_len != entry->session.id_len ||
-            memcmp( session->id, entry->session.id,
+        if( session_id_len != entry->session.id_len ||
+            memcmp( session_id, entry->session.id,
                     entry->session.id_len ) != 0 )
         {
             continue;
@@ -135,7 +138,10 @@
     return( ret );
 }
 
-int mbedtls_ssl_cache_set( void *data, const mbedtls_ssl_session *session )
+int mbedtls_ssl_cache_set( void *data,
+                           unsigned char const *session_id,
+                           size_t session_id_len,
+                           const mbedtls_ssl_session *session )
 {
     int ret = 1;
 #if defined(MBEDTLS_HAVE_TIME)
@@ -167,8 +173,11 @@
         }
 #endif
 
-        if( memcmp( session->id, cur->session.id, cur->session.id_len ) == 0 )
+        if( session_id_len == cur->session.id_len &&
+            memcmp( session_id, cur->session.id, cur->session.id_len ) == 0 )
+        {
             break; /* client reconnected, keep timestamp for session id */
+        }
 
 #if defined(MBEDTLS_HAVE_TIME)
         if( oldest == 0 || cur->timestamp < oldest )
diff --git a/library/ssl_srv.c b/library/ssl_srv.c
index 40ad490..784ab2d 100644
--- a/library/ssl_srv.c
+++ b/library/ssl_srv.c
@@ -2784,10 +2784,9 @@
         return;
 #endif
 
-    session_tmp.id_len = session->id_len;
-    memcpy( session_tmp.id, session->id, session->id_len );
-
     ret = ssl->conf->f_get_cache( ssl->conf->p_cache,
+                                  session->id,
+                                  session->id_len,
                                   &session_tmp );
     if( ret != 0 )
         goto exit;
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index 67fcebf..c26f68b 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -3411,7 +3411,10 @@
         ssl->session->id_len != 0 &&
         resume == 0 )
     {
-        if( ssl->conf->f_set_cache( ssl->conf->p_cache, ssl->session ) != 0 )
+        if( ssl->conf->f_set_cache( ssl->conf->p_cache,
+                                    ssl->session->id,
+                                    ssl->session->id_len,
+                                    ssl->session ) != 0 )
             MBEDTLS_SSL_DEBUG_MSG( 1, ( "cache did not store session" ) );
     }