数字签名的编程使用

数字签名介绍
1.数字签名
数字签名（又称公钥数字签名、电子签章）是一种类似写在纸上的普通的物理签名，但是使用了公钥加密领域的技术实现，用于鉴别数字信息的方法。一套数字签名通常定义两种互补的运算，一个用于签名，另一个用于验证。
2.数字签名模型

3.什么是数字签名
带有密钥（公钥和私钥）的消息摘要算法，是非对称加密算法和消息摘要算法结合体

4.数字签名的特点
（1）用于签名的信息私有，用于验证的信息公有，且这两种信息必须成对出现
（2）签名时使用原始数据和私钥，验证时需要原始数据、公钥和签名值
（3）私钥仅用于签名，公钥仅用于验证
（4）实际使用时，通常对原始数据先做摘要处理，再用私钥进行签名

5.常用数字签名算法：
（1）RSA Signature（JDK）
（2）DSA Signature（JDK）
（3）ECDSA Signature（需要 Bouncy Castle 支持）
6.数字签名作用
1.验证数据完整性
2.认证数据来源
3.抗否认

RSASignature 算法的编程使用
1.RSA 签名算法概念
将 RSA 公钥密码算法按照数字签名的方式运用

2.RSA 签名算法分类（JDK实现）
（1）MD (MD2withRSA、MD5withRSA)
（2）SHA (SHA1withRSA、SHA256withRSA、SHA384withRSA、SHA512withRSA)

3.编程实例

package key.base64;

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;

public class RSASigatureUtil {
    public static final String KEY_ALGORITHM="RSA";
    public static final String RSA_PUBLIC_KEY="RSA_PUBLIC_KEY";
    public static final String RSA_PRIVATE_KEY="RSA_PRIVATE_KEY";
    public static final String SIGNATURE_ALGRITHM="SHA1withRSA";
    /**
     * 生成公私秘钥对
     */
    public static Map initKey()  throws Exception{
        KeyPairGenerator keyPairGenerator=KeyPairGenerator.getInstance("RSA");
        KeyPair keyPair=keyPairGenerator.generateKeyPair();
        RSAPublicKey publicKey=(RSAPublicKey) keyPair.getPublic();
        RSAPrivateKey privateKey=(RSAPrivateKey) keyPair.getPrivate();
        Map keyMap=new HashMap<>();
        keyMap.put(RSA_PUBLIC_KEY, publicKey);
        keyMap.put(RSA_PRIVATE_KEY, privateKey);
        return keyMap;
    }

    public static byte[] getPublicKey(Map keyMap)  {
        RSAPublicKey publicKey=(RSAPublicKey) keyMap.get(RSA_PUBLIC_KEY);
        return publicKey.getEncoded();

    }
    public static byte[] getPrivateKey(Map keyMap)  {
        RSAPrivateKey privateKey=(RSAPrivateKey) keyMap.get(RSA_PRIVATE_KEY);
        return privateKey.getEncoded();

    }

    /**
     * 对原始数据用私钥进行数字签名
     */
    public static byte[] sign(byte[] data,byte[] privateKey) throws Exception{
        PKCS8EncodedKeySpec keySpec=new PKCS8EncodedKeySpec(privateKey);
        KeyFactory keyFactory=KeyFactory.getInstance(KEY_ALGORITHM);
        PrivateKey priKey=keyFactory.generatePrivate(keySpec);

        Signature signature=Signature.getInstance(SIGNATURE_ALGRITHM);
        signature.initSign(priKey);
        signature.update(data);
        return signature.sign();
    }

    /**
     * 根据原始的数据、公钥、签名进行验证
     */
    public static boolean verify(byte[] data,byte[] publicKey,byte[] sign) throws Exception{
        X509EncodedKeySpec keySpec=new X509EncodedKeySpec(publicKey);
        KeyFactory keyFactory=KeyFactory.getInstance(KEY_ALGORITHM);
        PublicKey pubKey=keyFactory.generatePublic(keySpec);

        Signature signature=Signature.getInstance(SIGNATURE_ALGRITHM);
        signature.initVerify(pubKey);
        signature.update(data);
        boolean isValid=signature.verify(sign);
        return isValid;
    }
    public static void main(Stringp[] args){
        //Test RSASiganture
        //初始化秘钥对
        Map keyMap=RSASigatureUtil.initKey();
        byte[] rsaPublicKey=RSASigatureUtil.getPublicKey(keyMap);
        byte[] rsaPrivateKey=RSASigatureUtil.getPrivateKey(keyMap);
        System.out.println("RSASignature PublicKey:"+BytesToHex.fromBytesToHex(rsaPublicKey));
        System.out.println("RSASignature PrivateKey:"+BytesToHex.fromBytesToHex(rsaPrivateKey));


        //Sign
        byte[] sign=RSASigatureUtil.sign(DATA.getBytes(), rsaPrivateKey);
        System.out.println("RSA Sign:"+BytesToHex.fromBytesToHex(sign));
        //Verify
        boolean isValid=RSASigatureUtil.verify(DATA.getBytes(), rsaPublicKey, sign);
        System.out.println("RSA　Verify:"+isValid);
    }
}

DSASignature 算法的编程使用
1.DSA 签名算法概念
DSA 算法实现就是 RSA 数字签名算法实现的简装版，仅支持 SHA 系列算法

2.DSA 签名算法分类（JDK实现）
SHA1withDSA

3.编程实现

package key.base64;

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 java.util.HashMap;
import java.util.Map;

public class DSASignatureUtil {
    public static final String  KEY_ALGORITHM="DSA";
    public static final int KEY_SIZE=1024;
    public static final String DSA_PUBLIC_KEY="DSA_PUBLIC_KEY";
    public static final String DSA_PRIVATE_KEY="DSA_PRIVATE_KEY";
    public static final String SIGNATURE_ALGORITHM="SHA1withDSA";


    /**
     * 生成公私钥秘钥对
     */
    public static Map initKey() throws Exception {
        KeyPairGenerator keyPairGenerator=KeyPairGenerator.getInstance(KEY_ALGORITHM);
        keyPairGenerator.initialize(KEY_SIZE);
        KeyPair keyPair=keyPairGenerator.generateKeyPair();
        DSAPublicKey publicKeyp=(DSAPublicKey) keyPair.getPublic();
        DSAPrivateKey privateKey=(DSAPrivateKey) keyPair.getPrivate();
        Map keyMap=new HashMap<>();
        keyMap.put(DSA_PUBLIC_KEY, publicKeyp);
        keyMap.put(DSA_PRIVATE_KEY, privateKey);
        return keyMap;
    }

    public static byte[] getPublicKey(Map keyMap) {
        DSAPublicKey key=(DSAPublicKey) keyMap.get(DSA_PUBLIC_KEY);
        return key.getEncoded();
    }
    public static byte[] getPrivateKey(Map keyMap) {
        DSAPrivateKey key=(DSAPrivateKey) keyMap.get(DSA_PRIVATE_KEY);
        return key.getEncoded();
    }

    /**
     * 对原始数据用私钥进行签名
     */
    public static byte[] sign(byte[] data,byte[] privateKey) throws Exception{
        PKCS8EncodedKeySpec keySpec=new PKCS8EncodedKeySpec(privateKey);
        KeyFactory keyFactory=KeyFactory.getInstance(KEY_ALGORITHM);
        PrivateKey prikey=keyFactory.generatePrivate(keySpec);

        Signature signature=Signature.getInstance(SIGNATURE_ALGORITHM);
        signature.initSign(prikey);
        signature.update(data);
        return signature.sign();
    }

    /**
     * 根据原始数据、公钥、签名值进行验证
     */
    public static boolean verify(byte[] data,byte[] publicKey,byte[] sign) throws Exception{
        X509EncodedKeySpec keySpec=new X509EncodedKeySpec(publicKey);
        KeyFactory keyFactory=KeyFactory.getInstance(KEY_ALGORITHM);
        PublicKey pubKey=keyFactory.generatePublic(keySpec);

        Signature signature=Signature.getInstance(SIGNATURE_ALGORITHM);
        signature.initVerify(pubKey);
        signature.update(data);
        boolean isValid=signature.verify(sign);
        return isValid;
    }
    public static void main(String[] args){
        //初始化秘钥对
        Map keyMap=DSASignatureUtil.initKey();
        byte[] dsaPublicKey=DSASignatureUtil.getPublicKey(keyMap);
        byte[] dsaPrivateKey=DSASignatureUtil.getPrivateKey(keyMap);
        System.out.println("DSASignature PublicKey:"+BytesToHex.fromBytesToHex(dsaPublicKey));;
        System.out.println("DSASignature PrivateKey:"+BytesToHex.fromBytesToHex(dsaPrivateKey));;
        //Sign
        byte[] sign=DSASignatureUtil.sign(DATA.getBytes(), dsaPrivateKey);
        System.out.println("DSA Sign:"+BytesToHex.fromBytesToHex(sign));;

        //Verify
        boolean isValid=DSASignatureUtil.verify(DATA.getBytes(), dsaPublicKey, sign);
        System.out.println("DSA Sign:"+isValid);
    }
}