c# - 具有 SHA-1 的 .NET RSACryptoServiceProvider 的 Java 等价物

Question

我在 C# 中有以下数据签名代码

RSACryptoServiceProvider rsa = new RSACryptoServiceProvider();

string PrivateKeyText = "<RSAKeyValue><Modulus>....</D></RSAKeyValue>";

rsa.FromXmlString(PrivateKeyText);

string data = "my data";        

byte[] SignedByteData = rsa.SignData(Encoding.UTF8.GetBytes(data), new SHA1CryptoServiceProvider());

我想在 Java (Android) 中重现相同的代码:

String modulusElem = "...";
String expElem = "...";

byte[] expBytes = Base64.decode(expElem, Base64.DEFAULT);
byte[] modulusBytes = Base64.decode(modulusElem, Base64.DEFAULT);

BigInteger modulus = new BigInteger(1, modulusBytes);
BigInteger exponent = new BigInteger(1, expBytes);

try {
    KeyFactory factory = KeyFactory.getInstance("RSA");

    Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1PADDING");

    String data = "my data";

    MessageDigest md = MessageDigest.getInstance("SHA-1");
    byte[] hashedData = md.digest(data.getBytes("UTF-8"));

    RSAPublicKeySpec pubSpec = new RSAPublicKeySpec(modulus, exponent);

    PublicKey publicKey = factory.generatePublic(pubSpec);

    cipher.init(Cipher.ENCRYPT_MODE, publicKey);

    byte[] SignedByteData = cipher.doFinal(hashedData);

} catch (Exception e){

}

但我得到不匹配的输出字节数组。我哪里错了，Cipher.getInstance(...) 中应该使用什么转换？

Answer 1

使用 Signature.getInstance("SHA1withRSA") .加密与签名生成不同。不同的填充机制。

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Afshin 更新

完整的解决方案。注意私有(private)指数的使用，即 <D> ，而不是公众<Exponent>

String modulusElem = "...";
String dElem = "...";

byte[] modulusBytes = Base64.decode(modulusElem, Base64.DEFAULT);
byte[] dBytes = Base64.decode(dElem, Base64.DEFAULT);

BigInteger modulus = new BigInteger(1, modulusBytes);
BigInteger d = new BigInteger(1, dBytes);

String data = "my data";            

try {
        Signature signature = Signature.getInstance("SHA1withRSA");

        KeyFactory factory = KeyFactory.getInstance("RSA");

        RSAPrivateKeySpec privateKeySpec = new RSAPrivateKeySpec(modulus, d);

        PrivateKey privateKey = factory.generatePrivate(privateKeySpec);

        signature.initSign(privateKey);

        signature.update(data.getBytes("UTF-8"));

        byte[] SignedByteData = signature.sign();

} catch(Exception e) {
    e.printStackTrace();
}