java 接口 加签 验签

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public class MD5Test {

    public static void main(String[] args) throws UnsupportedEncodingException {
        String s = "123";
        byte[] result = getMD5Bytes(s.getBytes());
        StringBuilder stringBuilder = new StringBuilder();
        for (byte temp : result) {
            if (temp >= 0 && temp < 16) {
                stringBuilder.append("0");
            }
            stringBuilder.append(Integer.toHexString(temp & 0xff));
        }
        System.out.println(s + ",MD5加密后:" + stringBuilder.toString());
    }

    private static byte[] getMD5Bytes(byte[] content) {
        try {
            MessageDigest md5 = MessageDigest.getInstance("MD5");
            return md5.digest(content);
        } catch (NoSuchAlgorithmException e) {
            throw new RuntimeException(e);
        }
    }
}

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package pattern;

import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;

import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.security.*;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.PKCS8EncodedKeySpec;

/**
 * 加签验签demo
 *  @Author 捡田螺的小男孩
 */
public class SignatureTest {
    //公钥字符串
    private static final String PUBLIC_KEY_STR = "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDaJzVjC5K6kbS2YE2fiDs6H8pB\n" +
 "JFDGEYqqJJC9I3E0Ebr5FsofdImV5eWdBSeADwcR9ppNbpORdZmcX6SipogKx9PX\n" +
 "5aAO4GPesroVeOs91xrLEGt/arteW8iSD+ZaGDUVV3+wcEdci/eCvFlc5PUuZJou\n" +
 "M2XZaDK4Fg2IRTfDXQIDAQAB";
    //私钥字符串
    private static final String PRIVATE_KEY_STR = "MIICdQIBADANBgkqhkiG9w0BAQEFAASCAl8wggJbAgEAAoGBANonNWMLkrqRtLZg\n" +
 "TZ+IOzofykEkUMYRiqokkL0jcTQRuvkWyh90iZXl5Z0FJ4APBxH2mk1uk5F1mZxf\n" +
 "pKKmiArH09floA7gY96yuhV46z3XGssQa39qu15byJIP5loYNRVXf7BwR1yL94K8\n" +
 "WVzk9S5kmi4zZdloMrgWDYhFN8NdAgMBAAECgYA9bz1Bn0i68b2KfqRdgOfs/nbe\n" +
 "0XNN1DLQp2t7WDfRCg01iI1zPkZgyFVZWtI85f5/uIrLs5ArLosL1oNuqqc0nNne\n" +
 "CvJK+ZxvA98Hx3ZqYTzDnleR054YhofL5awbhSciYVic204DOG1rhSsYWMqtX7J7\n" +
 "3geoWL7TYdMfYXcCAQJBAPMMKsz6ZJh98EeQ1tDG5gpAGWFQkYNrxZDelP/LjeO0\n" +
 "TP3XkQnIpcaZoCs7V/rRGRGMWwQ2BUdc/01in89ZZ5ECQQDlx2oBc1CtOAm2UAhN\n" +
 "1xWrPkZWENQ53wTrwXO4qbTGDfBKon0AehLlGCSqxQ71aufLkNO7ZlX0IHTAlnk1\n" +
 "TvENAkAGSEQ69CXxgx/Y2beTwfBkR2/gghKg0QJUUkyLqBlMz3ZGAXJwTE1sqr/n\n" +
 "HiuSAiGhwH0ByNuuEotO1sPGukrhAkAMK26a2w+nzPL+u+hkrwKPykGRZ1zGH+Cz\n" +
 "19AYNKzFXJGgclCqiMydY5T1knBDYUEbj/UW1Mmyn1FvrciHoUG1AkAEMEIuDauz\n" +
 "JabEAU08YmZw6OoDGsukRWaPfjOEiVhH88p00veM1R37nwhoDMGyEGXVeVzNPvk7\n" +
 "cELg28MSRzCK";


    public static void main(String[] args) throws SignatureException, NoSuchAlgorithmException, InvalidKeyException, IOException, InvalidKeySpecException {
        //原始报文
        String plain = "欢迎大家关注我的公众号，捡田螺的小男孩";
        //加签
        byte[] signatureByte = sign(plain);
        System.out.println("原始报文是:" + plain);
        System.out.println("加签结果:");
        System.out.println(new BASE64Encoder().encode(signatureByte));
        //验签
        boolean verifyResult = verify(plain, signatureByte);
        System.out.println("验签结果:" + verifyResult);
    }

    /**
     * 加签方法
     * @param plain
     * @return
     * @throws NoSuchAlgorithmException
     * @throws InvalidKeyException
     * @throws UnsupportedEncodingException
     * @throws SignatureException
     */
    private static byte[] sign(String plain) throws NoSuchAlgorithmException, InvalidKeyException, UnsupportedEncodingException, SignatureException {
        //根据对应算法，获取签名对象实例
        Signature signature = Signature.getInstance("SHA256WithRSA");
        //获取私钥，加签用的是私钥，私钥一般是在配置文件里面读的，这里为了演示方便，根据私钥字符串生成私钥对象
        PrivateKey privateKey = getPriveteKey(PRIVATE_KEY_STR);
        //初始化签名对象
        signature.initSign(privateKey);
        //把原始报文更新到对象
        signature.update(plain.getBytes("UTF-8"));
        //加签
 return signature.sign();
    }

    /**
     * 验签方法
     * @param plain
     * @param signatureByte
     * @return
     * @throws NoSuchAlgorithmException
     * @throws InvalidKeyException
     * @throws IOException
     * @throws SignatureException
     * @throws InvalidKeySpecException
     */
    private static boolean verify(String plain, byte[] signatureByte) throws NoSuchAlgorithmException, InvalidKeyException, IOException, SignatureException, InvalidKeySpecException {
        //获取公钥
        PublicKey publicKey = getPublicKey(PUBLIC_KEY_STR);
        //根据对应算法，获取签名对象实例
        Signature signature = Signature.getInstance("SHA256WithRSA");
        //初始化签名对象
        signature.initVerify(publicKey);
        //把原始报文更新到签名对象
        signature.update(plain.getBytes("UTF-8"));
        //进行验签
 return signature.verify(signatureByte);
    }

    private static PublicKey getPublicKey(String publicKeyStr) throws InvalidKeySpecException, IOException {
        PublicKey publicKey = null;
        try {
            java.security.spec.X509EncodedKeySpec bobPubKeySpec = new java.security.spec.X509EncodedKeySpec(
                    new BASE64Decoder().decodeBuffer(publicKeyStr));
            // RSA对称加密算法
            java.security.KeyFactory keyFactory;
            keyFactory = java.security.KeyFactory.getInstance("RSA");
            // 生成公钥对象
            publicKey = keyFactory.generatePublic(bobPubKeySpec);
           } catch (NoSuchAlgorithmException e) {
             e.printStackTrace();
            }
 return publicKey;
      }

    private static PrivateKey getPriveteKey(String privateKeyStr) {
        PrivateKey privateKey = null;
        PKCS8EncodedKeySpec priPKCS8;
        try {
            priPKCS8 = new PKCS8EncodedKeySpec(new BASE64Decoder().decodeBuffer(privateKeyStr));
            KeyFactory keyf = KeyFactory.getInstance("RSA");
            privateKey = keyf.generatePrivate(priPKCS8);
        } catch (IOException | NoSuchAlgorithmException | InvalidKeySpecException e) {
            e.printStackTrace();
        }
 return privateKey;
    }
}

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转自：https://cloud.tencent.com/developer/article/1665989