diff --git a/library/ssl_msg.c b/library/ssl_msg.c
index 6cee53a..9c2d615 100644
--- a/library/ssl_msg.c
+++ b/library/ssl_msg.c
@@ -457,6 +457,53 @@
     }
 }
 
+#if defined(MBEDTLS_SSL_PROTO_SSL3)
+
+#define SSL3_MAC_MAX_BYTES   20  /* MD-5 or SHA-1 */
+
+/*
+ * SSLv3.0 MAC functions
+ */
+static void ssl_mac( mbedtls_md_context_t *md_ctx,
+                     const unsigned char *secret,
+                     const unsigned char *buf, size_t len,
+                     const unsigned char *ctr, int type,
+                     unsigned char out[SSL3_MAC_MAX_BYTES] )
+{
+    unsigned char header[11];
+    unsigned char padding[48];
+    int padlen;
+    int md_size = mbedtls_md_get_size( md_ctx->md_info );
+    int md_type = mbedtls_md_get_type( md_ctx->md_info );
+
+    /* Only MD5 and SHA-1 supported */
+    if( md_type == MBEDTLS_MD_MD5 )
+        padlen = 48;
+    else
+        padlen = 40;
+
+    memcpy( header, ctr, 8 );
+    header[ 8] = (unsigned char)  type;
+    header[ 9] = (unsigned char)( len >> 8 );
+    header[10] = (unsigned char)( len      );
+
+    memset( padding, 0x36, padlen );
+    mbedtls_md_starts( md_ctx );
+    mbedtls_md_update( md_ctx, secret,  md_size );
+    mbedtls_md_update( md_ctx, padding, padlen  );
+    mbedtls_md_update( md_ctx, header,  11      );
+    mbedtls_md_update( md_ctx, buf,     len     );
+    mbedtls_md_finish( md_ctx, out              );
+
+    memset( padding, 0x5C, padlen );
+    mbedtls_md_starts( md_ctx );
+    mbedtls_md_update( md_ctx, secret,    md_size );
+    mbedtls_md_update( md_ctx, padding,   padlen  );
+    mbedtls_md_update( md_ctx, out,       md_size );
+    mbedtls_md_finish( md_ctx, out                );
+}
+#endif /* MBEDTLS_SSL_PROTO_SSL3 */
+
 int mbedtls_ssl_encrypt_buf( mbedtls_ssl_context *ssl,
                              mbedtls_ssl_transform *transform,
                              mbedtls_record *rec,
@@ -573,7 +620,7 @@
 #if defined(MBEDTLS_SSL_PROTO_SSL3)
         if( transform->minor_ver == MBEDTLS_SSL_MINOR_VERSION_0 )
         {
-            unsigned char mac[SSL_MAC_MAX_BYTES];
+            unsigned char mac[SSL3_MAC_MAX_BYTES];
             ssl_mac( &transform->md_ctx_enc, transform->mac_enc,
                      data, rec->data_len, rec->ctr, rec->type, mac );
             memcpy( data + rec->data_len, mac, transform->maclen );