c# - aspnet core加密和解密字符串

Question

我正在尝试使用一些非常标准的算法来解密字符串。

public static string DecryptString(string cipherText)
{
    string keyString = string.Empty;

    // Check whether the environment variable exists.
    keyString = Environment.GetEnvironmentVariable("EncryptKey");

    if (keyString == null)
    {
        keyString = "E546C8DF278CD5931069B522E695D4F2";
    }

    var fullCipher = Convert.FromBase64String(cipherText);
    using (var aesAlg = Aes.Create())
    {
        byte[] iv = new byte[aesAlg.BlockSize / 8];
        var cipher = new byte[16];

        Buffer.BlockCopy(fullCipher, 0, iv, 0, iv.Length);
        Buffer.BlockCopy(fullCipher, iv.Length, cipher, 0, iv.Length);
        var key = Encoding.UTF8.GetBytes(keyString);

        string result;
        using (var decryptor = aesAlg.CreateDecryptor(key, iv))
        using (var msDecrypt = new MemoryStream(cipher))
        using (var csDecrypt = new CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read))
        using (var srDecrypt = new StreamReader(csDecrypt))
        {
            result = srDecrypt.ReadToEnd();
        }
        return result;
    }
}

我不断收到错误:

System.Security.Cryptography.CryptographicException: Specified padding mode is not valid for this algorithm.

我试过很多这样的方法

var iv = new byte[16];
var cipher = new byte[16];

或者

var iv = aesAlg.IV;

此时我仍然遇到错误。我做错了什么？

Answer 1

需要做两处改动

var cipher = new byte[fullCipher.Length - iv.Length];

和

Buffer.BlockCopy(fullCipher, iv.Length, cipher, 0, fullCipher.Length - iv.Length);