java - 签名 validator 在检查自身时返回 false

Question

我不明白为什么下面的代码在检查自身时返回false？

import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.NoSuchAlgorithmException;
import java.security.Signature;
import java.security.SignatureException;
import java.security.NoSuchProviderException;
import java.security.*;


public class HelloWorld
{
  public static void main(String[] args)
  {
    KeyPair keyPair;
    String data = "test";

        try {

          KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance("DSA");
          keyPairGen.initialize(512);
          keyPair =  keyPairGen.genKeyPair();

          Signature sign = Signature.getInstance("SHA1withDSA", "SUN");
          sign.initSign(keyPair.getPrivate());
          sign.update(data.getBytes());

          byte[] encoded = sign.sign();

          sign = Signature.getInstance("SHA1withDSA", "SUN");
          sign.initVerify(keyPair.getPublic());
          sign.update(encoded);
          System.out.println("Checked: "  + sign.verify(encoded)); // Testing with itself returns false????

        } catch (NoSuchAlgorithmException ex) {
            ex.printStackTrace();
        } catch (SignatureException ex) {
             ex.printStackTrace();
        } catch (NoSuchProviderException ex) {
             ex.printStackTrace();
        } catch (InvalidKeyException ex) {
            ex.printStackTrace();
        }
  }
}

私钥/公钥有问题？ 我真的很困惑。

Answer 1

您更新了错误的内容，请更改此行

sign.update(encoded);

到此

sign.update(data.getBytes());

获得公钥后。