如何使用非十六进制 IV 对 CBC Blowfish 进行加密

Question

我对加密的工作原理还比较陌生，但是有人要求我使用 Blowfish CBC 加密来加密和解密一个值。现在我在这上面花了很多时间，我认为我是正确的，直到他们寄给我他们希望我使用的 IV，这让我很困惑。我的印象是 IV 必须是一个十六进制值，但是，他们给我发了一个 IV，看起来是这样的：cl5PxDOt.

我设法生成的代码如下所示：

function Run()
{
    var key = "enter your key";
    var value = "Enter your test value";
    var iv = StringToByteArray("enter your 16 char hex value");

    var encryptedValue = CbcBlowfishEncrypt(value, key, iv);
    var decryptedValue = CbcBlowfishDecrypt(encryptedValue, key, iv);
}

private string CbcBlowfishEncrypt(string strValue, string key, byte[] iv)
{
    byte[] inputBytes = Encoding.UTF8.GetBytes(strValue);
    BlowfishEngine engine = new BlowfishEngine();
    CbcBlockCipher blockCipher = new CbcBlockCipher(engine);
    PaddedBufferedBlockCipher cipher = new PaddedBufferedBlockCipher(blockCipher);
    KeyParameter keyParam = new KeyParameter(Convert.FromBase64String(key));
    ParametersWithIV keyParamWithIV = new ParametersWithIV(keyParam, iv, 0, 8);

    cipher.Init(true, keyParamWithIV);
    byte[] outputBytes = new byte[cipher.GetOutputSize(inputBytes.Length)];
    int length = cipher.ProcessBytes(inputBytes, outputBytes, 0);
    cipher.DoFinal(outputBytes, length); //Do the final block
    var c = BitConverter.ToString(outputBytes);
    string encryptedInput = Convert.ToBase64String(outputBytes);
    var result = BitConverter.ToString(outputBytes).Replace("-", "");
    return result;
}

private string CbcBlowfishDecrypt(string strValue, string key, byte[] iv)
{
    BlowfishEngine engine = new BlowfishEngine();
    CbcBlockCipher blockCipher = new CbcBlockCipher(engine);
    PaddedBufferedBlockCipher cipher = new PaddedBufferedBlockCipher(blockCipher);
    KeyParameter keyParam = new KeyParameter(Convert.FromBase64String(key));
    ParametersWithIV keyParamWithIV = new ParametersWithIV(keyParam, iv, 0, 8);

    cipher.Init(false, keyParamWithIV);
    byte[] out1 = Hex.Decode(strValue);
    byte[] out2 = new byte[cipher.GetOutputSize(out1.Length)];
    int len2 = cipher.ProcessBytes(out1, 0, out1.Length, out2, 0);
    cipher.DoFinal(out2, len2);
    return Encoding.UTF8.GetString(out2);
}

public static byte[] StringToByteArray(string hex)
{
    return Enumerable.Range(0, hex.Length)
        .Where(x => x % 2 == 0)
        .Select(x => Convert.ToByte(hex.Substring(x, 2), 16))
        .ToArray();
}

我希望有人能告诉我如何修改上面的代码以使用示例 iv：cl5PxDOt.

编辑：这是我尝试过的方法，但我每次都得到 pad block corrupted：

var newIv = "cl5PxDOt";
var newByteIv = newIv.ToArray().Select(Convert.ToByte).ToArray();
var newDecryptedValue = CbcBlowfishDecrypt(ospToken, key, newByteIv);
//var newDecryptedValue = Encoding.UTF8.GetBytes(newIv) -- Also tried this, but same result.

at Org.BouncyCastle.Crypto.Paddings.Pkcs7Padding.PadCount(Byte[] input)
at Org.BouncyCastle.Crypto.Paddings.PaddedBufferedBlockCipher.DoFinal(Byte[] output, Int32 outOff)

Answer 1

如果密钥不是 Base64 解码而是 UTF-8 编码，即在 CbcBlowfishDecrypt()（和 CbcBlowfishEncrypt()）行

中，则可以解密密文

KeyParameter keyParam = new KeyParameter(Convert.FromBase64String(key));

将被替换为

KeyParameter keyParam = new KeyParameter(Encoding.UTF8.GetBytes(key));

UTF-8 编码的密钥长度为 448 位，因此是有效密钥（Blowfish 定义的密钥长度在 32 到 448 位之间）。

IV 可以用模拟方式而不是当前实现方式进行 UTF-8 编码。

如何使用非十六进制 IV 对 CBC Blowfish 进行加密

How to CBC Blowfish encrypt with non hex IV

c#

encryption

bouncycastle

blowfish

cbc-mode