IllegalArgumentException ChaCha20 需要 128 位或 256 位密钥

Question

如何将字符串转换为 128 或 256 位密钥以进行 chacha20 加密。

    ChaCha20Encryptor chaCha20Encryptor = new ChaCha20Encryptor();
    byte[] data = chaCha20Encryptor.encrypt(plaintext.getBytes(),key2.getBytes());
    String enStr = BaseUtilityHelper.encodeBase64URLSafeString(data);
    encryptedTv.setText(enStr);

ChaCha20Encryptor

public class ChaCha20Encryptor implements Encryptor {

    private final byte randomIvBytes[] = {0, 1, 2, 3, 4, 5, 6, 7};

    static {
        Security.addProvider(new BouncyCastleProvider());
    }

    @Override
    public byte[] encrypt(byte[] data, byte[] randomKeyBytes) throws IOException, InvalidKeyException,
            InvalidAlgorithmParameterException, InvalidCipherTextException {

        ChaChaEngine cipher = new ChaChaEngine();
        cipher.init(true, new ParametersWithIV(new KeyParameter(randomKeyBytes), randomIvBytes));

        byte[] result = new byte[data.length];
        cipher.processBytes(data, 0, data.length, result, 0);
        return result;
    }

    @Override
    public byte[] decrypt(byte[] data, byte[] randomKeyBytes)
            throws InvalidKeyException, InvalidAlgorithmParameterException, IOException,
            IllegalStateException, InvalidCipherTextException {

        ChaChaEngine cipher = new ChaChaEngine();
        cipher.init(false, new ParametersWithIV(new KeyParameter(randomKeyBytes), randomIvBytes));

        byte[] result = new byte[data.length];
        cipher.processBytes(data, 0, data.length, result, 0);
        return result;
    }

    @Override
    public int getKeyLength() {
        return 32;
    }

    @Override
    public String toString() {
        return "ChaCha20()";
    }
}

在哪里

private String key2 = "19920099-564A-4869-99B3-363F8145C0BB";
private String plaintext = "Hello";

我也尝试过不同的键。但它需要 key2 将其转换为 128 或 256 位。我已经搜索过SO。并找到一些链接

Java 256-bit AES Password-Based Encryption

Turn String to 128-bit key for AES

但这些看起来与我的要求无关

Answer 1

您的密钥（没有破折号）是完全有效的 128 位十六进制密钥。它是 32 个字符，即 16 个字节 => 128 位。

你所要做的就是：

1. 删除破折号key2.replace("-","");
2. 将十六进制字符串转换为其字节[] 表示。我个人使用可用于 java 1.7 及更高版本的javax.xml.bind.DatatypeConverter。像这样使用它：DatatypeConverter.parseHexBinary(hexString);

您的完整通话应如下所示：

chaCha20Encryptor.encrypt(
             plaintext.getBytes(),
             DatatypeConverter.parseHexBinary(key2.replace("-","")));