数字签名算法RSA

一 背景介绍

数字签名：带有密钥（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。

私钥签名、公钥验证。

常用算法：RSA、DSA、ECDSA

二 RSA介绍

包括MD和SHA两类

三 Java代码实现

package com.imooc.security.rsa2;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 ImoocRSA {private static String src = "cakin 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.执行签名PKCS8EncodedKeySpec pkcs8EncodedKeySpec = new PKCS8EncodedKeySpec(rsaPrivateKey.getEncoded());KeyFactory keyFactory = KeyFactory.getInstance("RSA");PrivateKey privateKey = keyFactory.generatePrivate(pkcs8EncodedKeySpec);Signature signature = Signature.getInstance("MD5withRSA");signature.initSign(privateKey);signature.update(src.getBytes());byte[] result = signature.sign();System.out.println("jdk rsa sign : " + Hex.encodeHexString(result));//3.验证签名X509EncodedKeySpec x509EncodedKeySpec = new X509EncodedKeySpec(rsaPublicKey.getEncoded());keyFactory = KeyFactory.getInstance("RSA");PublicKey publicKey = keyFactory.generatePublic(x509EncodedKeySpec);signature = Signature.getInstance("MD5withRSA");signature.initVerify(publicKey);signature.update(src.getBytes());boolean bool = signature.verify(result);System.out.println("jdk rsa verify : " + bool);} catch (Exception e) {e.printStackTrace();}}}

四 实现效果

jdk rsa sign : 64b62967438d05f8f9837a089aaecd3b1379fd8eef89b924632536deb95d94d8389da456014ee953a1ac1befe44612c61b750b48c8574b98a9855a07a724e7e4

jdk rsa verify : true

五 应用场景