Java 实现常见的非对称加密算法

package com.ss.utils;

import javax.crypto.Cipher;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.NoSuchAlgorithmException;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.Base64;
import java.util.HashMap;
import java.util.Map;

public class RsaUtil {
  public static final String KEY_TYPE_PRIVATE_KEY = "privateKey";
  public static final String KEY_TYPE_PUBLIC_KEY = "publicKey";

  /**
   * 生成公钥和私钥
   *
   * @return
   * @throws NoSuchAlgorithmException
   */
  public static Map<String, String> generateKey() throws NoSuchAlgorithmException {
    Map<String, String> resultMap = new HashMap<>();
    KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA");
    KeyPair keyPair = keyPairGenerator.generateKeyPair();
    Base64.Encoder encoder = Base64.getEncoder();
    resultMap.put(KEY_TYPE_PRIVATE_KEY, encoder.encodeToString(keyPair.getPrivate().getEncoded()));
    resultMap.put(KEY_TYPE_PUBLIC_KEY, encoder.encodeToString(keyPair.getPublic().getEncoded()));
    return resultMap;
  }

  /**
   * RSA加密
   * @param key
   * @param content
   * @param keyType
   * @return
   * @throws Exception
   */
  public static String rsaEncrypt(String key, String content, String keyType) throws Exception {
    return rsa(key, content.getBytes(), keyType, Cipher.ENCRYPT_MODE);
  }

  /**
   * RSA解密
   * @param key
   * @param content
   * @param keyType
   * @return
   * @throws Exception
   */
  public static String rsaDecrypt(String key, String content, String keyType) throws Exception {
    return rsa(key, Base64.getDecoder().decode(content), keyType, Cipher.DECRYPT_MODE);
  }

  private static String rsa(String key, byte[] content, String keyType, int mode) throws Exception {
    Cipher cipher = Cipher.getInstance("RSA");
    KeyFactory keyFactory = KeyFactory.getInstance("RSA");
    if (KEY_TYPE_PRIVATE_KEY.equals(keyType)) {
      cipher.init(mode, keyFactory.generatePrivate(new PKCS8EncodedKeySpec(Base64.getDecoder().decode(key))));
    } else {
      cipher.init(mode, keyFactory.generatePublic(new X509EncodedKeySpec(Base64.getDecoder().decode(key))));
    }
    byte[] bytes = cipher.doFinal(content);
    return mode == Cipher.DECRYPT_MODE ? new String(bytes) : Base64.getEncoder().encodeToString(bytes);
  }

  public static void main(String[] args) throws Exception {
    String content = "大王叫我来巡山呐";

    //生成密钥对
    Map<String, String> keyMap = generateKey();
    System.out.println("私钥：" + keyMap.get(KEY_TYPE_PRIVATE_KEY));
    System.out.println("公钥：" + keyMap.get(KEY_TYPE_PUBLIC_KEY));

    //私钥加密，公钥解密
    String privateKeyData = rsaEncrypt(keyMap.get(KEY_TYPE_PRIVATE_KEY), content, KEY_TYPE_PRIVATE_KEY);
    System.out.println("私钥加密：" + privateKeyData);
    System.out.println("公钥解密：" + rsaDecrypt(keyMap.get(KEY_TYPE_PUBLIC_KEY), privateKeyData, KEY_TYPE_PUBLIC_KEY));

    //公钥加密，私钥解密
    String publicKeyData = rsaEncrypt(keyMap.get(KEY_TYPE_PUBLIC_KEY), content, KEY_TYPE_PUBLIC_KEY);
    System.out.println("公钥加密：" + publicKeyData);
    System.out.println("私钥解密：" + rsaDecrypt(keyMap.get(KEY_TYPE_PRIVATE_KEY), publicKeyData, KEY_TYPE_PRIVATE_KEY));
  }
}

私钥：MIIEvgIBADANBgkqhkiG9w0BAQEFAASCBKgwggSkAgEAAoIBAQDQPZnj0+/uh5jG0/rqVsXKLve7wTw2LVEwdBhm+SPrLoHYb4+6idNeF4bWgTqNRs2hfewq5cyiwXujT+eqp0g1ebSLWSUWzBsktynQMggxb8IwtnFYzmZX7BSAUudrfTre74RtKS0krYY5PCXCGR/EGbbXMVv1m2S59BrkWEI8c/iORhRAJ5/pqRW/51cIimPx9iTYx/QZC4VsCRi8ZrBaXcJhEi4Y/YzOFhfITID4ATis0Z3yw3FVybKzJo3Nexupcec5qaLBlwuDkY6E4NgQq51bjBCUB78RgXFLdaVtfBu9Vr7pRdqrh7sD//kpiicjiLJvmcLG9egXrkHRlm2TAgMBAAECggEAes75hM0mwOujBA9b+Pu3pedRHp91XRYYvZSaF5ByyG4jEXuprf8+ck05riOEXnEVMFpM/3eK2al1uviSzafeA/uEqHGoV+uDToHe3PPEtTMNuSC/c/o1jUCjTpKV/GRcZcGnvaD9CJZ1hCeetPuQKlxn4j0v2IcOPkRh36zVU0SZJKu5Ltt6iyGbpk6qqlpLnX93Ez5weWLnuolgjF34JBDQpc/zZjHwC8/avE81cJ3dUQR55l9QiwZUoMQ2eDWO1UcPAEqRssNAwEHbQJFSJmqtvg1yuSSvPIGB5ATPlTu7EoOLFMOQm3qoAxX7/FR9uU50wHivyZrRyKV4CdiLcQKBgQDuj6bh1WUQRIBU5ZOtljbs73RdYYbS1uUHubizQ3rqrNo3+TmaVu+7H3DPPI0L21YVpjXuPMUVkix+KA7HiDqULxx0yZMsdqXmggOT2QFEjGdueMFAJw09jAHnCIwuxmn3f94XAvV6N+Hfhjy31RGPQhjFGn6QQ16a3NI46CD6VwKBgQDfdorB9Wm0H6QJ8AYAQuHAiFJnXeOzN0q2407F5kx8XkAKwKaI7ybGZbiYESxFTe0AdVQlYRJbAby1iUW/OGOS+Ia5buzCo+BqrP6RxzLDYVClyXS3WFSLPKko6WIscS+uOF36mWWn34YYH/ktT8B/hUNFUD+PEctkrklONkZZJQKBgQCsn9hTbHYgKmFujV2qa5s9IhzjAZJs+MFsMLD9TuQf8opJnJdZHnWEw0B/RUKPBN0q90XpKaI3dLmrZFMlgWdaGSkPPVm4//YWcZgjIREwyCSEJO85+8gx9CDgTCgcJMlDJgzQO/zjvpI8i8deAtkc/+gqoHxa6dUIXKfmM9rBKwKBgFxIv0sUh5+8hWkZN9E5zbNOWQGZM6Tai791ph1yW1ntLnOCVgQtB41dits6FFdWtC7BRYveR89Pq1gpJaWvqueSPUktNxe2x8ImSUd4xU0Mzlp5FPt2vgt2dMGRiFqkL7W6T41jdija1az231fIHM5NAZgJaQYzqhSdKWbkYS8FAoGBAOciP4bEln64PnvuZtYnZNvt/5PHB4ssZ3S1WExyTtI7328ZKAsi3F7PjxCh7gviXfEI2t3AcVwpPaJYveL3Zg/jl2x6zNSLDW8kgNhAJE221u3pZefeidvIWwki/OXWtRqyoACteLnEb6lbM3tKdltWZOryQTiXqGdTluLEQLE0
公钥：MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEA0D2Z49Pv7oeYxtP66lbFyi73u8E8Ni1RMHQYZvkj6y6B2G+PuonTXheG1oE6jUbNoX3sKuXMosF7o0/nqqdINXm0i1klFswbJLcp0DIIMW/CMLZxWM5mV+wUgFLna3063u+EbSktJK2GOTwlwhkfxBm21zFb9ZtkufQa5FhCPHP4jkYUQCef6akVv+dXCIpj8fYk2Mf0GQuFbAkYvGawWl3CYRIuGP2MzhYXyEyA+AE4rNGd8sNxVcmysyaNzXsbqXHnOamiwZcLg5GOhODYEKudW4wQlAe/EYFxS3WlbXwbvVa+6UXaq4e7A//5KYonI4iyb5nCxvXoF65B0ZZtkwIDAQAB
私钥加密：V9kG4o3nceI4a19t/V5431v9Ek1PiV3FZokfnRNBor/RBymwDX4rsGNHEYuyN6/sbbD56r3ij5tUpShXFlcHrzVH4IfD4ySbvNNeMs2FrZLF3zvQmwRKDPH6SJ0DEczi5N97Vfh4b2tfyLT8iX3t9LPWgEj5mB7MXiYPc56mza+ZAqDduxWWsm6Emm81uKn97wZnasg8zXlDbhRttVTWhszbDhrFqsgd2sb8ZZUZIuiGTaIg7U6Slc5x9uS3UVACXXVyMCmxiVutQtg3Z4kt80ruh7xO0hl4cWk6P2Tg0ncaIQn/5vKsO2UXr/EsCb2rchWN3ZBHTVyQ83v/EHDtQw==
公钥解密：大王叫我来巡山呐
公钥加密：aartOyClfEIz1JT5nghpTbXxLZEOovm+vwvg+u3Tw8t5LOF+C7Gg/uxUP8Hm5jEkN6JfBHaMWTKg0RQ2xf3CCuXcLIpYVCOUwADwd05E8guEfZBT8FIp8jghCz2j+lAIiTfGZvsK9qUdZEmwTAEjV6uP4avF6njriglGJ4KhcYXEO66tOJWe2nQ1hyYXEHS43h9F0dtlWDjF6Xr6wdmUALnhprHDwKPdT/1T8p7+M5Fz7fUC7TJulBHWCSZvhgl405PvN+iTv7VysBJKRPks1JnmMe6BxFyhxXZfNRHmUyQvTMSfWt/A5gOy8ao/SOwWv0QMSh5NbocSd/tpjn27kw==
私钥解密：大王叫我来巡山呐

package com.ss.utils;

import java.security.*;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.Base64;
import java.util.HashMap;
import java.util.Map;

public class SignatureUtil {
  public static final String KEY_TYPE_PRIVATE_KEY = "privateKey";
  public static final String KEY_TYPE_PUBLIC_KEY = "publicKey";

  /**
   * 生成公钥和私钥
   *
   * @return
   * @throws NoSuchAlgorithmException
   */
  public static Map<String, String> generateKey() throws NoSuchAlgorithmException {
    Map<String, String> resultMap = new HashMap<>();
    KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA");
    KeyPair keyPair = keyPairGenerator.generateKeyPair();
    Base64.Encoder encoder = Base64.getEncoder();
    resultMap.put(KEY_TYPE_PRIVATE_KEY, encoder.encodeToString(keyPair.getPrivate().getEncoded()));
    resultMap.put(KEY_TYPE_PUBLIC_KEY, encoder.encodeToString(keyPair.getPublic().getEncoded()));
    return resultMap;
  }

  /**
   * 私钥签名
   * @param privateKeyStr
   * @param content
   * @return
   * @throws Exception
   */
  public static String generateSignature(String privateKeyStr, String content) throws Exception {
    KeyFactory keyFactory = KeyFactory.getInstance("RSA");
    Signature signature = Signature.getInstance("SHA1withRSA");
    PrivateKey privateKey = keyFactory.generatePrivate(new PKCS8EncodedKeySpec(Base64.getDecoder().decode(privateKeyStr)));
    signature.initSign(privateKey);
    signature.update(content.getBytes());
    return Base64.getEncoder().encodeToString(signature.sign());
  }

  /**
   * 公钥验证
   * @param publicKeyStr
   * @param content
   * @param sign
   * @return
   * @throws Exception
   */
  public static boolean verifySignature(String publicKeyStr, String content, String sign) throws Exception {
    KeyFactory keyFactory = KeyFactory.getInstance("RSA");
    Signature signature = Signature.getInstance("SHA1withRSA");
    PublicKey publicKey = keyFactory.generatePublic(new X509EncodedKeySpec(Base64.getDecoder().decode(publicKeyStr)));
    signature.initVerify(publicKey);
    signature.update(content.getBytes());
    return signature.verify(Base64.getDecoder().decode(sign));
  }

  public static void main(String[] args) throws Exception {
    String content = "大王叫我来巡山呐";

    //生成密钥对
    Map<String, String> keyMap = generateKey();

    //私钥签名
    String sign = generateSignature(keyMap.get(KEY_TYPE_PRIVATE_KEY), content);
    System.out.println("私钥签名：" + sign);

    //公钥验证
    boolean verifyResult = verifySignature(keyMap.get(KEY_TYPE_PUBLIC_KEY), content, sign);
    System.out.println("公钥验证：" + verifyResult);

    //将内容做下修改，再进行公钥验证
    boolean verifyResult2 = verifySignature(keyMap.get(KEY_TYPE_PUBLIC_KEY), content + "啦啦啦啦", sign);
    System.out.println("公钥验证：" + verifyResult2);
  }
}

私钥签名：XDWeOUVZhXNPl58mcmRK8ht9TAhnREc+NlnSs2b6PCJuj29ABuoXsjZeJqSspGw8hm9ckHVSTrUt8pX4BFBFzrINDRBsx3TdLp2L8nMkhjFUfo0qcyZo8ReEGFCNr0ergkq2W1Me/5W40GrQz4cJcQ4KV/QWzD8YHWcnDvKg9Q0nXJSngyhJTzUB8o/pgo/tmkA9+bWW212UD9nzEXu5aoPEcYyoo3iFWRX5o9Jgg6ZF+exmWizwZHkg4eD1zC5IN3m4yRS6GRbnZInEuDsOMp9W7HouDLUirkFZiSkyW+DVto+L6CE5eNBrWC52zxiNkVBlkyYKOatSpcrQrtnyiQ==
公钥验证：true
公钥验证：false