diff --git a/src/libstrongswan/crypto/pkcs5.c b/src/libstrongswan/crypto/pkcs5.c
index e48a9ad9d..4851d3f96 100644
--- a/src/libstrongswan/crypto/pkcs5.c
+++ b/src/libstrongswan/crypto/pkcs5.c
@@ -113,6 +113,11 @@ static bool verify_padding(crypter_t *crypter, chunk_t *blob)
 {
 	uint8_t padding, count;
 
+	if (!blob->len)
+	{
+		return FALSE;
+	}
+
 	padding = count = blob->ptr[blob->len - 1];
 
 	if (padding > crypter->get_block_size(crypter))