diff --git a/include/mbedtls/ssl_internal.h b/include/mbedtls/ssl_internal.h
index 1553200ce..82f91412b 100644
--- a/include/mbedtls/ssl_internal.h
+++ b/include/mbedtls/ssl_internal.h
@@ -1223,7 +1223,7 @@ int mbedtls_ssl_encrypt_buf( mbedtls_ssl_context *ssl,
                              mbedtls_record *rec,
                              int (*f_rng)(void *, unsigned char *, size_t),
                              void *p_rng );
-int mbedtls_ssl_decrypt_buf( mbedtls_ssl_context *ssl,
+int mbedtls_ssl_decrypt_buf( mbedtls_ssl_context const *ssl,
                              mbedtls_ssl_transform *transform,
                              mbedtls_record *rec );
 
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index 69ba0dba5..39a32c8de 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -2349,7 +2349,7 @@ int mbedtls_ssl_encrypt_buf( mbedtls_ssl_context *ssl,
     return( 0 );
 }
 
-int mbedtls_ssl_decrypt_buf( mbedtls_ssl_context *ssl,
+int mbedtls_ssl_decrypt_buf( mbedtls_ssl_context const *ssl,
                              mbedtls_ssl_transform *transform,
                              mbedtls_record *rec )
 {