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使用RSA非对称密钥进行数字签名与验签

最近项目中有用到RSA这种加密方式,所以写篇文章记录下。关于RSA这种非对称密钥的介绍及实现原理,本文就不累述,相关资料网上一大堆,本文只作RSA在JAVA中的使用测试

作为初探RSA的话,我觉得以下贴出的两个测试类就绰绰有余。

一、第一个简明测试类——总结了RSA的三个使用步骤:

1、初始化密钥,生成一对公钥和私钥

2、通常都是私钥签名(执行签名)

3、用公钥验证签名

import org.apache.shiro.codec.Hex;

import java.security.*;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;

/**
 * Created by admin on 2017/3/23.
 */
public class TestRSA {

    private static String thecontent="wo de qian ming nei rong";

    public static void main(String[] args) {
        test();
    }
    public  static  void test(){

        try {
            //---------------------------初始化秘钥------------------
            KeyPairGenerator keyPairGenerator=KeyPairGenerator.getInstance("RSA");
            //修改秘钥长度
            keyPairGenerator.initialize(512);
            //生成一对秘钥
            KeyPair keyPair=keyPairGenerator.generateKeyPair();
            //获取公钥私钥
            RSAPublicKey rsaPublicKey=(RSAPublicKey)keyPair.getPublic();
            RSAPrivateKey rsaPrivateKey=(RSAPrivateKey)keyPair.getPrivate();

            //----------------------------执行签名(用私钥签名)---------------------
            //生成签名用的密钥
            PKCS8EncodedKeySpec pkcs8EncodedKeySpec=new PKCS8EncodedKeySpec(rsaPrivateKey.getEncoded());
            KeyFactory keyFactory=KeyFactory.getInstance("RSA");
            PrivateKey privateKey=keyFactory.generatePrivate(pkcs8EncodedKeySpec);//转化
            //生成签名对象
            Signature signature=Signature.getInstance("MD5withRSA");
            //初始化签名
            signature.initSign(privateKey);
            signature.update(thecontent.getBytes());//里面是需要处理的内容
            byte [] result = signature.sign();//执行签名 得到一个返回数组
            System.out.println("jdk rsa sign:" + Hex.encodeToString(result));//将返回结果转换成十进制展示

            //--------------------------------验证签名(用公钥验证)------------------------------
            X509EncodedKeySpec x509EncodedKeySpec=new X509EncodedKeySpec(rsaPublicKey.getEncoded());
            /*keyFactory=KeyFactory.getInstance("RSA");*/
            PublicKey publicKey=keyFactory.generatePublic(x509EncodedKeySpec);//转化
            /*signature=Signature.getInstance("MD5withRSA");*/
            //初始化验证方式
            signature.initVerify(publicKey);
            signature.update(thecontent.getBytes());
            boolean bool= signature.verify(result);//执行验签
            System.out.println("jdk rsa verify:"+bool);

        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

二、第二个测试工具类(摘自网上) 把获取公钥密钥、签名验签等方法封装,以便在项目中使用

import java.io.ByteArrayOutputStream;
import java.security.Key;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.Signature;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.HashMap;
import java.util.Map;

import javax.crypto.Cipher;

import org.apache.commons.codec.binary.Base64;

/**
 * RSA算法加密/解密工具类。
 *
 *
 */
/**
 * <p>
 *  rsa 加密工具
 */
public class RSAUtil {

    /**
     * 加密算法RSA
     */
    public static final String KEY_ALGORITHM = "RSA";

    /**
     * 签名算法
     */
    public static final String SIGNATURE_ALGORITHM = "MD5withRSA";

    /**
     * 获取公钥的key
     */
    private static final String PUBLIC_KEY = "RSAPublicKey";

    /**
     * 获取私钥的key
     */
    private static final String PRIVATE_KEY = "RSAPrivateKey";

    /**
     * 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
     */
    private static final int MAX_DECRYPT_BLOCK = 128;

    /**
     * <p>
     * 生成密钥对(公钥和私钥)
     * </p>
     *
     * @return
     * @throws Exception
     */
    public static Map<String, Object> genKeyPair() throws Exception {
        KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance(KEY_ALGORITHM);
        keyPairGen.initialize(1024);
        KeyPair keyPair = keyPairGen.generateKeyPair();
        RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();
        RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();
        Map<String, Object> keyMap = new HashMap<String, Object>(2);
        keyMap.put(PUBLIC_KEY, publicKey);
        keyMap.put(PRIVATE_KEY, privateKey);
        return keyMap;
    }

    /**
     * <p>
     * 用私钥对信息生成数字签名
     * </p>
     *
     * @param data 已加密数据
     * @param privateKey 私钥(BASE64编码)
     *
     * @return
     * @throws Exception
     */
    public static String sign(byte[] data, String privateKey) throws Exception {
        byte[] keyBytes = decode(privateKey);
        PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
        PrivateKey privateK = keyFactory.generatePrivate(pkcs8KeySpec);
        Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);
        signature.initSign(privateK);
        signature.update(data);
        return encode(signature.sign());
    }

    /**
     * <p>
     * 校验数字签名
     * </p>
     *
     * @param data 已加密数据
     * @param publicKey 公钥(BASE64编码)
     * @param sign 数字签名
     *
     * @return
     * @throws Exception
     *
     */
    public static boolean verify(byte[] data, String publicKey, String sign)
            throws Exception {
        byte[] keyBytes = decode(publicKey);
        X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
        PublicKey publicK = keyFactory.generatePublic(keySpec);
        Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);
        signature.initVerify(publicK);
        signature.update(data);
        return signature.verify(decode(sign));
    }

    /**
     * <P>
     * 私钥解密
     * </p>
     *
     * @param encryptedData 已加密数据
     * @param privateKey 私钥(BASE64编码)
     * @return
     * @throws Exception
     */
    public static byte[] decryptByPrivateKey(byte[] encryptedData, String privateKey)
            throws Exception {
        byte[] keyBytes = decode(privateKey);
        PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
        Key privateK = keyFactory.generatePrivate(pkcs8KeySpec);
        Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
        cipher.init(Cipher.DECRYPT_MODE, privateK);
        int inputLen = encryptedData.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(encryptedData, offSet, MAX_DECRYPT_BLOCK);
            } else {
                cache = cipher.doFinal(encryptedData, offSet, inputLen - offSet);
            }
            out.write(cache, 0, cache.length);
            i++;
            offSet = i * MAX_DECRYPT_BLOCK;
        }
        byte[] decryptedData = out.toByteArray();
        out.close();
        return decryptedData;
    }

    /**
     * <p>
     * 公钥解密
     * </p>
     *
     * @param encryptedData 已加密数据
     * @param publicKey 公钥(BASE64编码)
     * @return
     * @throws Exception
     */
    public static byte[] decryptByPublicKey(byte[] encryptedData, String publicKey)
            throws Exception {
        byte[] keyBytes = decode(publicKey);
        X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
        Key publicK = keyFactory.generatePublic(x509KeySpec);
        Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
        cipher.init(Cipher.DECRYPT_MODE, publicK);
        int inputLen = encryptedData.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(encryptedData, offSet, MAX_DECRYPT_BLOCK);
            } else {
                cache = cipher.doFinal(encryptedData, offSet, inputLen - offSet);
            }
            out.write(cache, 0, cache.length);
            i++;
            offSet = i * MAX_DECRYPT_BLOCK;
        }
        byte[] decryptedData = out.toByteArray();
        out.close();
        return decryptedData;
    }

    /**
     * <p>
     * 公钥加密
     * </p>
     *
     * @param data 源数据
     * @param publicKey 公钥(BASE64编码)
     * @return
     * @throws Exception
     */
    public static byte[] encryptByPublicKey(byte[] data, String publicKey)
            throws Exception {
        byte[] keyBytes = decode(publicKey);
        X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
        Key publicK = keyFactory.generatePublic(x509KeySpec);
        // 对数据加密
        Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
        cipher.init(Cipher.ENCRYPT_MODE, publicK);
        int inputLen = data.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, offSet, MAX_ENCRYPT_BLOCK);
            } else {
                cache = cipher.doFinal(data, offSet, inputLen - offSet);
            }
            out.write(cache, 0, cache.length);
            i++;
            offSet = i * MAX_ENCRYPT_BLOCK;
        }
        byte[] encryptedData = out.toByteArray();
        out.close();
        return encryptedData;
    }

    /**
     * <p>
     * 私钥加密
     * </p>
     *
     * @param data 源数据
     * @param privateKey 私钥(BASE64编码)
     * @return
     * @throws Exception
     */
    public static byte[] encryptByPrivateKey(byte[] data, String privateKey)
            throws Exception {
        //用BASE64编码解密私钥
        byte[] keyBytes =decode(privateKey);
        PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
        Key privateK = keyFactory.generatePrivate(pkcs8KeySpec);
        //对数据内容加密
        Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());//Algorithm:算法
        cipher.init(Cipher.ENCRYPT_MODE, privateK);
        int inputLen = data.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, offSet, MAX_ENCRYPT_BLOCK);
            } else {
                cache = cipher.doFinal(data, offSet, inputLen - offSet);
            }
            out.write(cache, 0, cache.length);
            i++;
            offSet = i * MAX_ENCRYPT_BLOCK;
        }
        byte[] encryptedData = out.toByteArray();
        out.close();
        return encryptedData;
    }

    /**
     * <p>
     * 获取私钥
     * </p>
     *
     * @param keyMap 密钥对
     * @return
     * @throws Exception
     */
    public static String getPrivateKey(Map<String, Object> keyMap)
            throws Exception {
        Key key = (Key) keyMap.get(PRIVATE_KEY);
        return encode(key.getEncoded());
    }

    /**
     * <p>
     * 获取公钥
     * </p>
     *
     * @param keyMap 密钥对
     * @return
     * @throws Exception
     */
    public static String getPublicKey(Map<String, Object> keyMap)
            throws Exception {
        Key key = (Key) keyMap.get(PUBLIC_KEY);
        return encode(key.getEncoded());
    }

    /**
     * base64 加密
     * @param bytes
     * @return
     * @throws Exception
     */
    public static String encode(byte[] bytes) throws Exception {
        return new String(Base64.encodeBase64(bytes));
    }
    /**
     * base64 解密
     * @param base64
     * @return
     * @throws Exception
     */
    public static byte[] decode(String base64) throws Exception {
        return Base64.decodeBase64(base64.getBytes());
    }

    public static void main(String[] args) throws Exception {


        Map<String, Object> keyMap = RSAUtil.genKeyPair();
        String publicKey = RSAUtil.getPublicKey(keyMap);
        String privateKey = RSAUtil.getPrivateKey(keyMap);

        System.out.println("publicKey:"+publicKey);
        System.out.println("privateKey:"+privateKey);

        String data="这是测试的文字?";

        /*对于RSA产生的公钥、私钥,我们可以有两种方式可以对信息进行加密解密。私钥加密-公钥解密 和 公钥加密-私钥解密。*/
       /* //公钥加密 私钥解密
        byte[] bytes= RSAUtil.encryptByPublicKey(data.getBytes(), publicKey);
        byte[] bytess= RSAUtil.decryptByPrivateKey(bytes, privateKey);
        System.out.println(new String(bytess));*/


        //私钥加密  公钥解密
        /*byte[] privateByte= RSAUtil.encryptByPrivateKey(data.getBytes(), privateKey);
        byte[] publicByte= RSAUtil.decryptByPublicKey(privateByte, publicKey);
        System.out.println(new String(publicByte));*/

        //私钥加密并生成数字签名     公钥验证
        byte[] privateBytes= RSAUtil.encryptByPrivateKey(data.getBytes(), privateKey);
        String signs=  RSAUtil.sign(privateBytes, privateKey);//生成数字签名
        System.out.println(signs);
        boolean bool= RSAUtil.verify(privateBytes, publicKey, signs);
        System.out.println(bool);

    }


}

未经允许不得转载:徐宏涛博客 » 使用RSA非对称密钥进行数字签名与验签

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