java - 使用 SHA256withRSA 签名后如何验证 signatureBytes？

Question

我正在使用“Windows-MY”KeyStore 签署一些文本。 我想使用我的私钥签名并使用公钥验证。

KeyStore keyStore = KeyStore.getInstance("Windows-MY");
                keyStore.load(null, null); 
Enumeration en = keyStore.aliases();
while (en.hasMoreElements()) {   
    KeyStore keyStore = KeyStore.getInstance("Windows-MY");
                keyStore.load(null, null);
    String alias = en.nextElement().toString();
    X509Certificate c = (X509Certificate) keyStore.getCertificate(alias);
    String serialNumber = c.getSerialNumber().toString();
    System.out.println("--" + aliasName);
                PrivateKey privateKey = (PrivateKey) keyStore.getKey(aliasName, null);
                PublicKey publicKey = (PublicKey) c.getPublicKey();
                Certificate[] chain = keyStore.getCertificateChain(aliasName);
    DataOutputStream fout = new DataOutputStream(outstream);
    // -------------------------------------------------------
    String data = "Monika";
    byte[] content = data.getBytes();
    Provider p = keyStore.getProvider();
    // ----------------------signature---start---------------------------

    Signature signature = Signature.getInstance("SHA256withRSA", p);
    System.out.println(" signature.getProvider():"+ signature.getProvider());
    signature.initSign(privateKey);
    signature.update(content);
    byte[] signatureBytes = signature.sign();
    System.out.println("signatureBytes-------------"+ signatureBytes.toString());
    // ----------------------signature----------end------------------

    // ------------------------verification---------------
    Signature signature1 = Signature.getInstance("SHA256withRSA", p);
    System.out.println(" signature1.getProvider():"+ signature1.getProvider());
    signature1.initVerify(publicKey);
    signature1.update(content);
    boolean verifies = signature1.verify(signatureBytes);
    System.out.println("signature verifies: " + verifies);
    // ------------------------------------------------
    fout.close();
} // while

输出:

privateKey:RSAPrivateKey [size=2048 bits, type=Exchange, container=AC0BEBA9-A361-4611-96D9-B365B671FBC3]
 signature.getProvider():SunMSCAPI version 1.6
signatureBytes-------------[B@1402d5a
 signature1.getProvider():SunRsaSign version 1.5
signature verifies: false

注意:

1. 我的私钥已经是 RSAPrivateKey 。
2. 签名提供程序是 SunMSCAPI。
3. 但我不知道 Provider for Verification with PrivateKey。

Answer 1

您的代码有几个问题:

1. 您只是使用来自您的 Windows keystore 的第一个 证书/公钥。这实际上可能是正确的，但 keystore 中可能有多个证书，然后您使用哪个证书进行验证只是巧合。

   String alias = en.nextElement().toString();
   X509Certificate c = (X509Certificate) keyStore.getCertificate(alias);
   PublicKey publicKey = c.getPublicKey();
   PrivateKey privateKey = (PrivateKey) keyStore.getKey(DSCName, null);
   

   您应该改为编写 keyStore.getCertificate(DSCName) 以确保它与私钥匹配。

2. 您正在无缘无故地生成一个 key (分别尝试转换现有 key )。您可以完全删除此代码。这也将解决您的 NullPointerException 问题:

   byte[] encodedPrivateKey = privateKey.getEncoded();
   KeyFactory keyFactory = KeyFactory.getInstance("RSA");
   PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(encodedPrivateKey);
   RSAPrivateKey privateKey1 = (RSAPrivateKey) keyFactory.generatePrivate(keySpec);
   

3. 您的问题中有很多不必要的代码，例如加载证书链，但从未使用它。这使得它更难修复。一个最小的(工作)示例如下所示:

   String alias = "myAlias";
   String myData = "data to encrypt";
   
   KeyStore keyStore = KeyStore.getInstance("Windows-MY");
   keyStore.load(null, null);
   
   X509Certificate cert = (X509Certificate) keyStore.getCertificate(alias);
   PrivateKey privateKey = (PrivateKey) keyStore.getKey(alias, null);
   PublicKey publicKey = cert.getPublicKey();
   
   Signature instance = Signature.getInstance("SHA256withRSA");
   instance.initSign(privateKey, new SecureRandom());
   instance.update(myData.getBytes("UTF-8"));
   byte[] signedBytes = instance.sign();
   
   instance.initVerify(publicKey);
   instance.update(myData.getBytes("UTF-8"));
   System.out.println(instance.verify(signedBytes));