Security Helper

following condition added to avoid exception
if (length - unpadding) <0

securityhelper/securityHelper.go

@@ -77,6 +77,10 @@ func AESDecrypt(encodedData, key []byte) ([]byte, error) {
 
 	unpadding := int(cipherText[length-1])
 
+	if (length - unpadding) < 0 {
+		return nil, errors.New("length of (length - unpadding) is less than 0")
+	}
+
 	return cipherText[:(length - unpadding)], nil
 }