Java实现数字签名

一 数字签名算法

　　带有秘钥(公钥,私钥)的消息摘要算法

　　验证数据完整性,认证数据来源,抗否认

　　OSI参考模型

　　私钥签名,公钥验证

　　RSA,DSA,ECDSA

二 数字签名算法RSA

经典算法

　　MD,SHA两类

　　 例子:jdkRSA 算法

package com.dzj.rsa;

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 org.apache.commons.codec.binary.Hex;

public class RSA {
    private static String src = "imooc security rsa";

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

    public static void jdkRSA() {
        try {
            // 1 初始化密钥
            KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA");
            keyPairGenerator.initialize(512);
            KeyPair keyPair = keyPairGenerator.generateKeyPair();

            RSAPublicKey rsaPublicKey = (RSAPublicKey) keyPair.getPublic();
            RSAPrivateKey rsaPrivateKey = (RSAPrivateKey) keyPair.getPrivate();

            // 2 私钥加密、公钥解密——加密
            // 用私钥进行签名
            PKCS8EncodedKeySpec pkcs8EncodedKeySpec = new PKCS8EncodedKeySpec(rsaPrivateKey.getEncoded());

            KeyFactory keyFactory = KeyFactory.getInstance("RSA");
            // 执行key的转化
            PrivateKey privateKey = keyFactory.generatePrivate(pkcs8EncodedKeySpec);

            // 声明一个签名对象 使用JDK实现
            Signature signature = Signature.getInstance("MD5withRSA");
            signature.initSign(privateKey);
            signature.update(src.getBytes());
            byte[] sign = signature.sign();
            System.out.println("私钥加密、公钥解密——加密:" + Hex.encodeHexString(sign));

            // 3私钥加密、公钥解密——解密
            X509EncodedKeySpec x509EncodedKeySpec = new X509EncodedKeySpec(rsaPublicKey.getEncoded());
            keyFactory = KeyFactory.getInstance("RSA");
            PublicKey publicKey = keyFactory.generatePublic(x509EncodedKeySpec);
            // 创建签名对象
            signature = Signature.getInstance("MD5withRSA");
            signature.initVerify(publicKey);
            signature.update(src.getBytes());
            boolean verify = signature.verify(sign);
            System.out.println("私钥加密、公钥解密——解密:" + verify);

        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

    }

}

数字签名算法----过程

三 数字签名算法DSA

　　DSS(Digital Signature Standard)数字签名标准

　　DSA(Digital Signature Algorithm)数字签名算法

　　DSA仅包含数字签名,没有办法进行加密通讯

　　RSA即包括加解密,又包括数字签名的算法

例子

package com.dzj.dsa;

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.DSAPrivateKey;
import java.security.interfaces.DSAPublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;

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

public class DSA {

    private static String src = "imooc security dsa";

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

    public static void jdkDSA() {
        try {
            // 1.初始化密钥
            KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("DSA");
            keyPairGenerator.initialize(512);
            KeyPair keyPair = keyPairGenerator.generateKeyPair();
            DSAPublicKey dsaPublicKey = (DSAPublicKey) keyPair.getPublic();
            DSAPrivateKey dsaPrivateKey = (DSAPrivateKey) keyPair.getPrivate();

            // 2.执行签名 私钥进行签名
            PKCS8EncodedKeySpec pkcs8EncodedKeySpec = new PKCS8EncodedKeySpec(dsaPrivateKey.getEncoded());
            KeyFactory keyFactory = KeyFactory.getInstance("DSA");
            PrivateKey privateKey = keyFactory.generatePrivate(pkcs8EncodedKeySpec);
            Signature signature = Signature.getInstance("SHA1withDSA");
            signature.initSign(privateKey);
            signature.update(src.getBytes());
            byte[] result = signature.sign();
            System.out.println("jdk dsa sign : " + Hex.encodeHexString(result));

            // 3.验证签名
            X509EncodedKeySpec x509EncodedKeySpec = new X509EncodedKeySpec(dsaPublicKey.getEncoded());
            keyFactory = KeyFactory.getInstance("DSA");
            PublicKey publicKey = keyFactory.generatePublic(x509EncodedKeySpec);
            signature = Signature.getInstance("SHA1withDSA");
            signature.initVerify(publicKey);
            signature.update(src.getBytes());
            boolean bool = signature.verify(result);
            System.out.println("jdk dsa verify : " + bool);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

}

四 数字签名算法ECDSA　　

　　微软

　　Ellipticc Curve Digital Signature Algorithm,椭圆曲线数字签名算法

　　速度快,强度高,签名短

　　例子:

package com.dzj.ecdsa;

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.ECPrivateKey;
import java.security.interfaces.ECPublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;

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

public class ECDSA {
    private static String src = "imooc security ecdsa";

    public static void main(String[] args) {

        jdkECDSA();

    }

    public static void jdkECDSA() {
        try {
            // 1 初始化密钥
            KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("EC");
            keyPairGenerator.initialize(256);
            KeyPair keyPair = keyPairGenerator.generateKeyPair();
            ECPublicKey ecPublicKey = (ECPublicKey) keyPair.getPublic();
            ECPrivateKey ecPrivateKey = (ECPrivateKey) keyPair.getPrivate();

            // 2 执行签名
            PKCS8EncodedKeySpec pkcs8EncodedKeySpec = new PKCS8EncodedKeySpec(ecPrivateKey.getEncoded());
            KeyFactory keyFactory = KeyFactory.getInstance("EC");
            PrivateKey privateKey = keyFactory.generatePrivate(pkcs8EncodedKeySpec);
            Signature signature = Signature.getInstance("SHA1withECDSA");
            signature.initSign(privateKey);
            signature.update(src.getBytes());
            byte[] sign = signature.sign();
            System.out.println("jdk ecdsa sign:" + Hex.encodeHexString(sign));

            // 3验证
            X509EncodedKeySpec x509EncodedKeySpec = new X509EncodedKeySpec(ecPublicKey.getEncoded());
            keyFactory = KeyFactory.getInstance("EC");
            PublicKey publicKey = keyFactory.generatePublic(x509EncodedKeySpec);
            signature = Signature.getInstance("SHA1withECDSA");
            signature.initVerify(publicKey);
            signature.update(src.getBytes());
            boolean verify = signature.verify(sign);
            System.out.println("jdk ecdsa verify:" + verify);
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

    }

}