Question

我正在尝试将我的RSA密钥对大小从1024升级到2048.我将在此处提供示例代码。

对于1024： 我的代码的第一步是使用Java代码构建签名

   try {
        // Generate Public & Private Keys
        KeyPairGenerator kpg = KeyPairGenerator.getInstance("RSA");
        kpg.initialize(1024);
        KeyPair keyPair = kpg.genKeyPair();

        RSAPublicKey key = (RSAPublicKey) keyPair.getPublic();
        System.out.println("Modulus");
        System.out.println(key.getModulus());


        String publicKey = encode(key.getModulus().toByteArray()) + encode(key.getPublicExponent().toByteArray());


        // Build the Signature
        Signature sig = Signature.getInstance("SHA256withRSA");
        sig.initSign(keyPair.getPrivate());
        seedData = seedData + "ABC";

        sig.update(seedData.getBytes("UTF-8"));
        String signature = encode(sig.sign());

        signatureString.append(signature);
        // Embed the public key in the signature
        int publicKeyLocation = signatureString.charAt(signatureString.length() - 2) % 40;
        // Add some random bytes at the end
        int randomBytesToAdd = signatureString.charAt(signatureString.length() - 10) % 9;
        System.out.println("Random bytes to add");
        System.out.println(randomBytesToAdd);
        System.out.println("Adding Random bytes that are:");
        String s = randomString(randomBytesToAdd);
        signatureString.insert(publicKeyLocation, s);
    } catch (Exception e) {

    }

    return signatureString.toString();
}

现在这个编码的字符串传递给.NET应用程序 我曾经在.NET应用程序中获取公钥和签名

 protected RSAParameters GetPublicKey(string encodedString)
    {
        int bytesToSkip = encodedString.Substring((encodedString.Length - 10), 1).ToCharArray()[0] % 9;
        int publicKeyStarts = bytesToSkip + encodedString.Substring((encodedString.Length - 2), 1).ToCharArray()[0] % 40;
        string keyString = encodedString.Substring(publicKeyStarts, 176);
        string modulusString = keyString.Substring(0, 172);
        string exponentString = keyString.Substring(172);
        RSAParameters publicKey = new RSAParameters();
        publicKey.Modulus = new byte[128];
        Array.Copy(System.Convert.FromBase64String(modulusString), 1, publicKey.Modulus, 0, 128);
        publicKey.Exponent = System.Convert.FromBase64String(exponentString);
        return publicKey;
    }

    protected byte[] GetSignature(string encodedString)
    {
        int bytesToSkip = encodedString.Substring((encodedString.Length - 10), 1).ToCharArray()[0] % 9;
        int publicKeyStarts = bytesToSkip + encodedString.Substring((encodedString.Length - 2), 1).ToCharArray()[0] % 40;
        String digSig = encodedString.Substring(0, publicKeyStarts - bytesToSkip) + encodedString.Substring(publicKeyStarts + 176);
        return System.Convert.FromBase64String(digSig);
    }

如果我将密钥对大小从1024更改为2048，那么我需要在.NET代码中进行哪些更改

我正在寻找的答案是：从生成的RSA公钥中我如何获得模数和指数的长度

Answer 1

我找到了从RSA公钥中获取模数和指数的大小或长度的答案

生成公钥的代码

  KeyPairGenerator kpg = KeyPairGenerator.getInstance("RSA");
        kpg.initialize(2048);
        KeyPair keyPair = kpg.genKeyPair();

        RSAPublicKey key = (RSAPublicKey) keyPair.getPublic();
        String publicKey = encode(key.getModulus().toByteArray()) +   encode(key.getPublicExponent().toByteArray());
       int modLength =  key.getModulus().toByteArray().length;
       int exponentLength = key.getPublicExponent().toByteArray().length;

从编码字符串（RSA公钥）中提取RSA参数（模数和指数）

1 个答案: