.net 加密错误：填充无效，无法移除

今天用System.Security.Cryptography加密。使用了AesManaged，报错：填充无效，无法移除。分析是解密失败，密文损坏，或者KEY，IV不正确。

using (AesManaged aesAlg = new AesManaged())
{
    aesAlg.Key = Encoding.Unicode.GetBytes("password");
    aesAlg.IV = aesAlg.Key;

     using (ICryptoTransform decryptor = aesAlg.CreateDecryptor())
                {
                    return decryptor.TransformFinalBlock(cipherBytes, 0, cipherBytes.Length);
                }

 }