diff --git a/library/cmac.c b/library/cmac.c
index 1a1200b52..409f67958 100644
--- a/library/cmac.c
+++ b/library/cmac.c
@@ -450,7 +450,7 @@ exit:
  */
 int mbedtls_aes_cmac_prf_128( const unsigned char *key, size_t key_length,
                               const unsigned char *input, size_t in_len,
-                              unsigned char *output )
+                              unsigned char output[16] )
 {
     int ret;
     const mbedtls_cipher_info_t *cipher_info;
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index 82181e36f..90b1d1667 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -614,20 +614,20 @@ static void ssl_calc_finished_ssl( mbedtls_ssl_context *, unsigned char *, int )
 #endif
 
 #if defined(MBEDTLS_SSL_PROTO_TLS1) || defined(MBEDTLS_SSL_PROTO_TLS1_1)
-static void ssl_calc_verify_tls( mbedtls_ssl_context *, unsigned char [36] );
+static void ssl_calc_verify_tls( mbedtls_ssl_context *, unsigned char * );
 static void ssl_calc_finished_tls( mbedtls_ssl_context *, unsigned char *, int );
 #endif
 
 #if defined(MBEDTLS_SSL_PROTO_TLS1_2)
 #if defined(MBEDTLS_SHA256_C)
 static void ssl_update_checksum_sha256( mbedtls_ssl_context *, const unsigned char *, size_t );
-static void ssl_calc_verify_tls_sha256( mbedtls_ssl_context *, unsigned char [32] );
+static void ssl_calc_verify_tls_sha256( mbedtls_ssl_context *, unsigned char * );
 static void ssl_calc_finished_tls_sha256( mbedtls_ssl_context *,unsigned char *, int );
 #endif
 
 #if defined(MBEDTLS_SHA512_C)
 static void ssl_update_checksum_sha384( mbedtls_ssl_context *, const unsigned char *, size_t );
-static void ssl_calc_verify_tls_sha384( mbedtls_ssl_context *, unsigned char [48] );
+static void ssl_calc_verify_tls_sha384( mbedtls_ssl_context *, unsigned char * );
 static void ssl_calc_finished_tls_sha384( mbedtls_ssl_context *, unsigned char *, int );
 #endif
 #endif /* MBEDTLS_SSL_PROTO_TLS1_2 */
@@ -1142,7 +1142,7 @@ int mbedtls_ssl_derive_keys( mbedtls_ssl_context *ssl )
 }
 
 #if defined(MBEDTLS_SSL_PROTO_SSL3)
-void ssl_calc_verify_ssl( mbedtls_ssl_context *ssl, unsigned char hash[36] )
+void ssl_calc_verify_ssl( mbedtls_ssl_context *ssl, unsigned char *hash )
 {
     mbedtls_md5_context md5;
     mbedtls_sha1_context sha1;
@@ -1191,7 +1191,7 @@ void ssl_calc_verify_ssl( mbedtls_ssl_context *ssl, unsigned char hash[36] )
 #endif /* MBEDTLS_SSL_PROTO_SSL3 */
 
 #if defined(MBEDTLS_SSL_PROTO_TLS1) || defined(MBEDTLS_SSL_PROTO_TLS1_1)
-void ssl_calc_verify_tls( mbedtls_ssl_context *ssl, unsigned char hash[36] )
+void ssl_calc_verify_tls( mbedtls_ssl_context *ssl, unsigned char *hash )
 {
     mbedtls_md5_context md5;
     mbedtls_sha1_context sha1;
@@ -1219,7 +1219,7 @@ void ssl_calc_verify_tls( mbedtls_ssl_context *ssl, unsigned char hash[36] )
 
 #if defined(MBEDTLS_SSL_PROTO_TLS1_2)
 #if defined(MBEDTLS_SHA256_C)
-void ssl_calc_verify_tls_sha256( mbedtls_ssl_context *ssl, unsigned char hash[32] )
+void ssl_calc_verify_tls_sha256( mbedtls_ssl_context *ssl, unsigned char *hash )
 {
     mbedtls_sha256_context sha256;
 
@@ -1240,7 +1240,7 @@ void ssl_calc_verify_tls_sha256( mbedtls_ssl_context *ssl, unsigned char hash[32
 #endif /* MBEDTLS_SHA256_C */
 
 #if defined(MBEDTLS_SHA512_C)
-void ssl_calc_verify_tls_sha384( mbedtls_ssl_context *ssl, unsigned char hash[48] )
+void ssl_calc_verify_tls_sha384( mbedtls_ssl_context *ssl, unsigned char *hash )
 {
     mbedtls_sha512_context sha512;