RES加密解密以及签名验签

RES加密解密以及签名验签

128位加密 Base64是jdk8自带的 分段式加密解密，满足超长字符串加密
代码较长请耐心

import java.io.ByteArrayOutputStream;
import java.security.*;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import javax.crypto.Cipher;
import java.util.Base64;
import java.util.HashMap;
import java.util.Map;


public class TestRSA {
    
    
    /**
     * RSA最大加密明文大小
     */
    private static final int MAX_ENCRYPT_BLOCK = 117;

    /**
     * RSA最大解密密文大小  可以是 128  256
     */
    private static final int MAX_DECRYPT_BLOCK = 128;

    /**
     *  可以是 1024  2048
     */
    private final static int KEY_SIZE = 1024;

    /**
     * 用于封装随机产生的公钥与私钥
     */
    private static Map<Integer, String> keyMap = new HashMap<Integer, String>();
    /**
     * 随机生成密钥对
     */
    public static void genKeyPair() throws Exception {
    
    
        // KeyPairGenerator类用于生成公钥和私钥对，基于RSA算法生成对象
        KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance("RSA");
        // 初始化密钥对生成器
        keyPairGen.initialize(KEY_SIZE, new SecureRandom());
        // 生成一个密钥对，保存在keyPair中
        KeyPair keyPair = keyPairGen.generateKeyPair();
        // 得到私钥
        RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();
        // 得到公钥
        RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();
        String publicKeyString = Base64.getEncoder().encodeToString(publicKey.getEncoded());
        // 得到私钥字符串
        String privateKeyString = Base64.getEncoder().encodeToString(privateKey.getEncoded());
        // 将公钥和私钥保存到Map
        //0表示公钥
        keyMap.put(0, publicKeyString);
        //1表示私钥
        keyMap.put(1, privateKeyString);
    }

    /**
     * RSA加密
     *
     * @param data 待加密数据
     * @param publicKey 公钥
     * @return
     */
    public static String encrypt(String data, String publicKey) throws Exception {
    
    
        byte[] decoded = Base64.getDecoder().decode(publicKey);
        RSAPublicKey pubKey = (RSAPublicKey) KeyFactory.getInstance("RSA").generatePublic(new X509EncodedKeySpec(decoded));
        Cipher cipher = Cipher.getInstance("RSA");
        cipher.init(Cipher.ENCRYPT_MODE, pubKey);
        int inputLen = data.getBytes().length;
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        int offset = 0;
        byte[] cache;
        int i = 0;
        // 对数据分段加密
        while (inputLen - offset > 0) {
    
    
            if (inputLen - offset > MAX_ENCRYPT_BLOCK) {
    
    
                cache = cipher.doFinal(data.getBytes(), offset, MAX_ENCRYPT_BLOCK);
            } else {
    
    
                cache = cipher.doFinal(data.getBytes(), offset, inputLen - offset);
            }
            out.write(cache, 0, cache.length);
            i++;
            offset = i * MAX_ENCRYPT_BLOCK;
        }
        byte[] encryptedData = out.toByteArray();
        out.close();
        // 获取加密内容使用base64进行编码,并以UTF-8为标准转化成字符串
        // 加密后的字符串
        String outStr = Base64.getEncoder().encodeToString(out.toByteArray());
        return outStr;
    }

    /**
     * RSA解密
     *
     * @param data 待解密数据
     * @param privateKey 私钥
     * @return
     */
    public static String decrypt(String data, String privateKey) throws Exception {
    
    
        byte[] decoded = Base64.getDecoder().decode(privateKey);
        RSAPrivateKey priKey = (RSAPrivateKey) KeyFactory.getInstance("RSA").generatePrivate(new PKCS8EncodedKeySpec(decoded));
        Cipher cipher = Cipher.getInstance("RSA");
        cipher.init(Cipher.DECRYPT_MODE, priKey);
        byte[] dataBytes = Base64.getDecoder().decode(data);
        int inputLen = dataBytes.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(dataBytes, offset, MAX_DECRYPT_BLOCK);
            } else {
    
    
                cache = cipher.doFinal(dataBytes, offset, inputLen - offset);
            }
            out.write(cache, 0, cache.length);
            i++;
            offset = i * MAX_DECRYPT_BLOCK;
        }
        byte[] decryptedData = out.toByteArray();
        out.close();
        // 解密后的内容
        return new String(decryptedData, "UTF-8");
    }

    /**
     * 签名
     *
     * @param data 待签名数据
     * @param privateKey 私钥
     * @return 签名
     */
    public static String sign(String data, String privateKey) throws Exception {
    
    
        byte[] decoded = Base64.getDecoder().decode(privateKey);
        RSAPrivateKey priKey = (RSAPrivateKey) KeyFactory.getInstance("RSA").generatePrivate(new PKCS8EncodedKeySpec(decoded));

        byte[] keyBytes = priKey.getEncoded();
        PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance("RSA");
        PrivateKey key = keyFactory.generatePrivate(keySpec);
        Signature signature = Signature.getInstance("MD5withRSA");
        signature.initSign(key);
        signature.update(data.getBytes());
       // return new String(Base64.encodeBase64(signature.sign()));

        byte[] signed = signature.sign();
        String sign = new String(Base64.getEncoder().encodeToString(signed));
        return sign;
    }

    /**
     * 验签
     *
     * @param srcData 原始字符串
     * @param publicKey 公钥
     * @param sign 签名
     * @return 是否验签通过
     */
    public static boolean verify(String srcData, String publicKey, String sign) throws Exception {
    
    
        byte[] decoded = Base64.getDecoder().decode(publicKey);
        RSAPublicKey pubKey = (RSAPublicKey) KeyFactory.getInstance("RSA").generatePublic(new X509EncodedKeySpec(decoded));

        byte[] keyBytes = pubKey.getEncoded();
        X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance("RSA");
        PublicKey key = keyFactory.generatePublic(keySpec);
        Signature signature = Signature.getInstance("MD5withRSA");
        signature.initVerify(key);
        signature.update(srcData.getBytes());
        return signature.verify(Base64.getDecoder().decode(sign.getBytes()));
    }

    public static void main(String[] args) {
    
    
        try {
    
    
            long temp = System.currentTimeMillis();
            // 生成密钥对

            genKeyPair();

            System.out.println("公钥:" + keyMap.get(0));
            System.out.println("私钥:" + keyMap.get(1));
            System.out.println("生成密钥消耗时间:" + (System.currentTimeMillis() - temp) / 1000.0 + "秒");
            // RSA加密
            String data = "#%第三sdfdsa*、？";
            String encryptData = encrypt(data,  keyMap.get(0));
            System.out.println("加密后内容:" + encryptData);
            System.out.println("加密消耗时间:" + (System.currentTimeMillis() - temp) / 1000.0 + "秒");

            // RSA解密
            String decryptData = decrypt(encryptData, keyMap.get(1));
            System.out.println("解密后内容:" + decryptData);
            System.out.println("解密消耗时间:" + (System.currentTimeMillis() - temp) / 1000.0 + "秒");
            // RSA签名
            String sign = sign(data, keyMap.get(1));
            System.out.println("签名消耗时间:" + (System.currentTimeMillis() - temp) / 1000.0 + "秒");
            // RSA验签
            boolean result = verify(data, keyMap.get(0), sign);
            System.out.println("验签结果:" + result);
            System.out.println("验签消耗时间:" + (System.currentTimeMillis() - temp) / 1000.0 + "秒");
        } catch (Exception e) {
    
    
            e.printStackTrace();
            System.out.print("加解密异常");
        }
    }
}