X509 RSA弹力城堡标志并验证Java中的纯文本

Question

我目前正在使用Bouncycastle编写一个Java程序，该程序使用RSA键对生成X509 SSL证书。

我已经能够成功创建SSL证书，但我也希望能够签署任意纯文本，并通过该签名来验证钥匙的所有权，通过验证针对纯文本的签名。

这些方法应该看起来像这样：

protected String SignData(String privateKey, String text)
{
    //return a signature
}

和

protected boolean verifySignature(String text, String signature, String pubKey)
{
    //return either true or false depending on whether the signature is valid or not
}

我使用以下内容成功生成了自签名的SSL证书：

protected X509Certificate generateCert()
{
    try
    {
        Security.addProvider(new BouncyCastleProvider());
        // generate a key pair
        KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA", "BC");
        keyPairGenerator.initialize(4096, new SecureRandom());
        KeyPair keyPair = keyPairGenerator.generateKeyPair();
        // build a certificate generator
        X509V3CertificateGenerator certGen = new X509V3CertificateGenerator();
        X500Principal dnName = new X500Principal("cn=example");
        // add some options
        certGen.setSerialNumber(BigInteger.valueOf(System.currentTimeMillis()));
        certGen.setSubjectDN(new X509Name("dc=name"));
        certGen.setIssuerDN(dnName); // use the same
        // yesterday
        certGen.setNotBefore(new Date(System.currentTimeMillis() - 24 * 60 * 60 * 1000));
        // in 2 years
        certGen.setNotAfter(new Date(System.currentTimeMillis() + 2 * 365 * 24 * 60 * 60 * 1000));
        certGen.setPublicKey(keyPair.getPublic());
        certGen.setSignatureAlgorithm("SHA256WithRSAEncryption");
        certGen.addExtension(X509Extensions.ExtendedKeyUsage, true, new ExtendedKeyUsage(KeyPurposeId.id_kp_timeStamping));
        // finally, sign the certificate with the private key of the same KeyPair
        X509Certificate cert = certGen.generate(keyPair.getPrivate(), "BC");
        return cert;
    }
    catch (Exception e)
    {
        e.printStackTrace();
        return null;
    }
}

Answer 1

找到解决方案：

签名：

        Signature rsaSign = Signature.getInstance("SHA256withRSA", "BC");
        rsaSign.initSign(pair.getPrivate());
        rsaSign.update(plaintext.getBytes("UTF-8"));
        byte[] signature = rsaSign.sign();
        return signature;

验证：

        rsaVerify = Signature.getInstance("SHA256withRSA", "BC");
        rsaVerify.initVerify(pubKey);
        rsaVerify.update(plaintext.getBytes("UTF-8"));
        return rsaVerify.verify(signature);