解密时无效的char或字符串长度

Question

每当我尝试在DB中调用存储密码的Decrypt函数时，我收到 Base-64字符数组或字符串的无效长度。解密代码：

public static string Decrypt(string encryptedText)
{

   // byte[] cipherTextBytes = Convert.FromBase64String(encryptedText)); OLD ONE
    byte[] cipherTextBytes = Convert.FromBase64String(encryptedText.Replace(' ', '+')); //NEW 
    byte[] keyBytes = new Rfc2898DeriveBytes(PasswordHash, Encoding.ASCII.GetBytes(SaltKey)).GetBytes(256 / 8);
    var symmetricKey = new RijndaelManaged() { Mode = CipherMode.CBC, Padding = PaddingMode.None };

    var decryptor = symmetricKey.CreateDecryptor(keyBytes, Encoding.ASCII.GetBytes(VIKey));
    var memoryStream = new MemoryStream(cipherTextBytes);
    var cryptoStream = new CryptoStream(memoryStream, decryptor, CryptoStreamMode.Read);
    byte[] plainTextBytes = new byte[cipherTextBytes.Length];

    int decryptedByteCount = cryptoStream.Read(plainTextBytes, 0, plainTextBytes.Length);
    memoryStream.Close();
    cryptoStream.Close();
    return Encoding.UTF8.GetString(plainTextBytes, 0, decryptedByteCount).TrimEnd("\0".ToCharArray());
}

我发现像这样转换字符串会导致此错误：

byte[] cipherTextBytes = Convert.FromBase64String(encryptedText)); OLD ONE

因此，应该这样做：

byte[] cipherTextBytes = Convert.FromBase64String(encryptedText.Replace(' ', '+')); 

但我仍然得到相同的错误，基本上我在谷歌上找到的所有解决方案都指向这种解决方案，这对我没有帮助。任何人都可以解释它有什么问题吗？感谢。