Rsa 工具类，公钥私钥生成，加解密-蒲公英云

包含分段加密和分段解密工具类：

/**
 * Rsa 工具类，公钥私钥生成，加解密
 *
 * @author : YZD
 * @date : 2020-12-9 22:59
 */
public class MyRsaUtils {
    /**
     * 测试加密内容
     */
    public static final String SRC = "测试加密内容";
    /**
     * 公钥
     */
    public static final String PUBLICKEY = "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCCuF6cl/Il6Npp7KxcaQyfepfnOs14Rs4klLrKKu0CJhsTv+VuYFOH37YV9eoKzG10xX99Zn/TIRIndDUNlOB6HbbMH046r4Ip7/XEr0XWfO+jAk8fQ9BTnLFBy3DtOqndpluqmzXuXVLpxd5lhu9zJgzGY2Ts016iY6p6Gda2OQIDAQAB";
    /**
     * 私钥
     */
    public static final String PRIVATEKEY = "MIICdQIBADANBgkqhkiG9w0BAQEFAASCAl8wggJbAgEAAoGBAIK4XpyX8iXo2mnsrFxpDJ96l+c6zXhGziSUusoq7QImGxO/5W5gU4ffthX16grMbXTFf31mf9MhEid0NQ2U4HodtswfTjqvginv9cSvRdZ876MCTx9D0FOcsUHLcO06qd2mW6qbNe5dUunF3mWG73MmDMZjZOzTXqJjqnoZ1rY5AgMBAAECgYAkFJGAtWvPzOKkRAAbDZ+/UQ4mc5OM9DYn4Klh7dE3O59Tpy7DdXD42uWeUB8GVgCML4sN6MG1W7ZwD2IpWoNOq4w8xah6y7B2YhyPXEqSJsIpWiZNlEWiwZbGoqBFN1261Pyy5dhfaspFKbH+qbEanx+ezv7UvzFwg5uUzS2lgQJBANENPTJa4QoMpj/GBBtl2tD7yFLtbMvykgk/7pF6FyF3RDNr+QQD/Ay/H74IVRCow0oWn1b05BXzGiiaWQZGhjECQQCgE7W0SAuCZngz374wIYBxg3SdW0aetgtnsMfV0wFL1czh2qakqgnuu6u+y1FTgeGhJDDVTjpiutTSbyCgf8aJAkBbbHPH8tCZ6YBHQZ0IMloorQQlqCm9Y58UJn555q/49cTAzEaByBBRrr/+BnzVJUkKvKwAhma9ZqyY9y9ZvDvxAkBhdb6SRa7kNLkIdDfaG/uUoQF18KWdaZ6mAeaZE7/dSQ1VkQcWiARGGnLlVeps2k3iCyPEKr23cKK0gD4wGbtpAkBtzQ7qjrfOm0zLRUJOt7D0EcDIR9IaRtk3n4XSoJ94rJDHv/Toe7pwMfWsPFdnLesx5iZ6J5I8U196qjvY13t5";
    /**
     * 算法
     */
    public static final String ALGORITHM = "RSA";
    /**
     * 一次解密的长度
     */
    private static final int MAX_DECRYPT_BLOCK = 128;
    /**
     * 一次加密的长度
     */
    private static final int MAX_ENCRYPT_BLOCK = 117;
    public static void main(String[] args) throws Exception {
        System.out.println("\n");
        // 分段加密 解密
        String byPublicKeySplit1 = encryptByPrivateKeySplit(MyRsaUtils.PRIVATEKEY, " ");
        String byPublicKeySplit2 = decryptByPublicKeySplit(MyRsaUtils.PUBLICKEY, byPublicKeySplit1);
        System.out.println("\n");
        RsaKeyPair keyPair = generateKeyPair();
        System.out.println("公钥：" + keyPair.getPublicKey());
        System.out.println("私钥：" + keyPair.getPrivateKey());
        System.out.println("\n");
        test1(keyPair);
        System.out.println("\n");
        test2(keyPair);
        System.out.println("\n");
    }
    /**
     * 公钥加密 私钥解密
     */
    private static void test1(RsaKeyPair keyPair) throws Exception {
        System.out.println("***************** 公钥加密私钥解密开始 *****************");
        String text1 = encryptByPublicKey(keyPair.getPublicKey(), MyRsaUtils.SRC);
        String text2 = decryptByPrivateKey(keyPair.getPrivateKey(), text1);
        System.out.println("加密前：" + MyRsaUtils.SRC);
        System.out.println("加密后：" + text1);
        System.out.println("解密后：" + text2);
        if (MyRsaUtils.SRC.equals(text2)) {
            System.out.println("解密字符串和原始字符串一致，解密成功");
        } else {
            System.out.println("解密字符串和原始字符串不一致，解密失败");
        }
        System.out.println("***************** 公钥加密私钥解密结束 *****************");
    }
    /**
     * 私钥加密 公钥解密
     *
     * @throws Exception /
     */
    private static void test2(RsaKeyPair keyPair) throws Exception {
        System.out.println("***************** 私钥加密公钥解密开始 *****************");
        String text1 = encryptByPrivateKey(keyPair.getPrivateKey(), MyRsaUtils.SRC);
        String text2 = decryptByPublicKey(keyPair.getPublicKey(), text1);
        System.out.println("加密前：" + MyRsaUtils.SRC);
        System.out.println("加密后：" + text1);
        System.out.println("解密后：" + text2);
        if (MyRsaUtils.SRC.equals(text2)) {
            System.out.println("解密字符串和原始字符串一致，解密成功");
        } else {
            System.out.println("解密字符串和原始字符串不一致，解密失败");
        }
        System.out.println("***************** 私钥加密公钥解密结束 *****************");
    }
    /**
     * 公钥解密
     *
     * @param publicKeyText 公钥
     * @param text          待解密的信息
     * @return /
     * @throws Exception /
     */
    public static String decryptByPublicKey(String publicKeyText, String text) throws Exception {
        X509EncodedKeySpec x509EncodedKeySpec = new X509EncodedKeySpec(Base64.decodeBase64(publicKeyText));
        KeyFactory keyFactory = KeyFactory.getInstance("RSA");
        PublicKey publicKey = keyFactory.generatePublic(x509EncodedKeySpec);
        Cipher cipher = Cipher.getInstance("RSA");
        cipher.init(Cipher.DECRYPT_MODE, publicKey);
        byte[] result = cipher.doFinal(Base64.decodeBase64(text));
        return new String(result);
    }
    /**
     * 分段 公钥解密
     *
     * @param publicKeyText 公钥
     * @param data          待解密的信息
     * @return /
     * @throws Exception /
     */
    public static String decryptByPublicKeySplit(String publicKeyText, String data) throws Exception {
        X509EncodedKeySpec x509EncodedKeySpec = new X509EncodedKeySpec(Base64.decodeBase64(publicKeyText));
        KeyFactory keyFactory = KeyFactory.getInstance("RSA");
        PublicKey publicKey = keyFactory.generatePublic(x509EncodedKeySpec);
        Cipher cipher = Cipher.getInstance("RSA");
        cipher.init(Cipher.DECRYPT_MODE, publicKey);
        byte[] decodeBase64 = Base64.decodeBase64(data);
        //得到报文密文的长度
        int inputLen = decodeBase64.length;
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        int offSet = 0;
        byte[] cache;
        int i = 0;
        // 对数据分段解密
        while (inputLen - offSet > 0) {
            if (inputLen - offSet > MAX_DECRYPT_BLOCK) {
                cache = cipher.doFinal(decodeBase64, offSet, MAX_DECRYPT_BLOCK);
            } else {
                cache = cipher.doFinal(decodeBase64, offSet, inputLen - offSet);
            }
            out.write(cache, 0, cache.length);
            i++;
            offSet = i * MAX_DECRYPT_BLOCK;
        }
        //解密后的数据
        byte[] byteArray = out.toByteArray();
        out.close();
        return new String(byteArray);
    }
    /**
     * 私钥加密
     *
     * @param privateKeyText 私钥
     * @param text           待加密的信息
     * @return /
     * @throws Exception /
     */
    public static String encryptByPrivateKey(String privateKeyText, String text) throws Exception {
        PKCS8EncodedKeySpec pkcs8EncodedKeySpec = new PKCS8EncodedKeySpec(Base64.decodeBase64(privateKeyText));
        KeyFactory keyFactory = KeyFactory.getInstance("RSA");
        PrivateKey privateKey = keyFactory.generatePrivate(pkcs8EncodedKeySpec);
        Cipher cipher = Cipher.getInstance("RSA");
        cipher.init(Cipher.ENCRYPT_MODE, privateKey);
        byte[] result = cipher.doFinal(text.getBytes());
        return Base64.encodeBase64String(result);
    }
    /**
     * 分段 私钥 加密
     *
     * @param privateKeyText 私钥
     * @param data           待加密的信息
     * @return /
     * @throws Exception /
     */
    public static String encryptByPrivateKeySplit(String privateKeyText, String data) throws Exception {
        // 加密时超过117字节就报错。为此采用分段加密的办法来加密
        PKCS8EncodedKeySpec pkcs8EncodedKeySpec = new PKCS8EncodedKeySpec(Base64.decodeBase64(privateKeyText));
        KeyFactory keyFactory = KeyFactory.getInstance("RSA");
        PrivateKey privateKey = keyFactory.generatePrivate(pkcs8EncodedKeySpec);
        Cipher cipher = Cipher.getInstance("RSA");
        cipher.init(Cipher.ENCRYPT_MODE, privateKey);
        byte[] encryptedData = data.getBytes();
        int inputLen = encryptedData.length;
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        int offSet = 0;
        byte[] cache;
        int i = 0;
        // 对数据分段加密  doFinal
        while (inputLen - offSet > 0) {
            if (inputLen - offSet > MAX_ENCRYPT_BLOCK) {
                cache = cipher.doFinal(encryptedData, offSet, MAX_ENCRYPT_BLOCK);
            } else {
                cache = cipher.doFinal(encryptedData, offSet, inputLen - offSet);
            }
            out.write(cache, 0, cache.length);
            i++;
            offSet = i * MAX_ENCRYPT_BLOCK;
        }
        byte[] byteArray = out.toByteArray();
        out.close();
        return Base64.encodeBase64String(byteArray);
    }
    /**
     * 私钥解密
     *
     * @param privateKeyText 私钥
     * @param text           待解密的文本
     * @return /
     * @throws Exception /
     */
    public static String decryptByPrivateKey(String privateKeyText, String text) throws Exception {
        PKCS8EncodedKeySpec pkcs8EncodedKeySpec5 = new PKCS8EncodedKeySpec(Base64.decodeBase64(privateKeyText));
        KeyFactory keyFactory = KeyFactory.getInstance("RSA");
        PrivateKey privateKey = keyFactory.generatePrivate(pkcs8EncodedKeySpec5);
        Cipher cipher = Cipher.getInstance("RSA");
        cipher.init(Cipher.DECRYPT_MODE, privateKey);
        byte[] result = cipher.doFinal(Base64.decodeBase64(text));
        return new String(result);
    }
    /**
     * 公钥加密
     *
     * @param publicKeyText 公钥
     * @param text          待加密的文本
     * @return /
     */
    public static String encryptByPublicKey(String publicKeyText, String text) throws Exception {
        X509EncodedKeySpec x509EncodedKeySpec2 = new X509EncodedKeySpec(Base64.decodeBase64(publicKeyText));
        KeyFactory keyFactory = KeyFactory.getInstance("RSA");
        PublicKey publicKey = keyFactory.generatePublic(x509EncodedKeySpec2);
        Cipher cipher = Cipher.getInstance("RSA");
        cipher.init(Cipher.ENCRYPT_MODE, publicKey);
        byte[] result = cipher.doFinal(text.getBytes());
        return Base64.encodeBase64String(result);
    }
    /**
     * 构建RSA密钥对
     *
     * @return /
     * @throws NoSuchAlgorithmException /
     */
    public static RsaKeyPair generateKeyPair() throws NoSuchAlgorithmException {
        KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA");
        keyPairGenerator.initialize(1024);
        KeyPair keyPair = keyPairGenerator.generateKeyPair();
        RSAPublicKey rsaPublicKey = (RSAPublicKey) keyPair.getPublic();
        RSAPrivateKey rsaPrivateKey = (RSAPrivateKey) keyPair.getPrivate();
        String publicKeyString = Base64.encodeBase64String(rsaPublicKey.getEncoded());
        String privateKeyString = Base64.encodeBase64String(rsaPrivateKey.getEncoded());
        return new RsaKeyPair(publicKeyString, privateKeyString);
    }
    /**
     * RSA密钥对对象
     */
    public static class RsaKeyPair {
        private final String publicKey;
        private final String privateKey;
        public RsaKeyPair(String publicKey, String privateKey) {
            this.publicKey = publicKey;
            this.privateKey = privateKey;
        }
        public String getPublicKey() {
            return publicKey;
        }
        public String getPrivateKey() {
            return privateKey;
        }
    }
}