package com.rsa; import java.security.KeyFactory; import java.security.KeyPair; import java.security.KeyPairGenerator; import java.security.NoSuchAlgorithmException; import java.security.SecureRandom; 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; public class Test { private static Map<Integer, String> keyMap = new HashMap<Integer, String>(); public static void main(String[] args) throws Exception { // TODO Auto-generated method stub // 用于封装随机产生的公钥与私钥 { // 生成公钥和私钥 genKeyPair(); // 加密字符串 String message = "df723820"; System.out.println("随机生成的公钥为:" + keyMap.get(0)); System.out.println("随机生成的私钥为:" + keyMap.get(1)); String messageEn = encrypt(message, keyMap.get(0)); System.out.println(message + "\t加密后的字符串为:" + messageEn); String messageDe = decrypt(messageEn, keyMap.get(1)); System.out.println("还原后的字符串为:" + messageDe); } } public static void genKeyPair() throws NoSuchAlgorithmException { // 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,密钥大小为96-1024位 keyPairGen.initialize(1024, new SecureRandom()); // 生成一个密钥对,保存在keyPair中 KeyPair keyPair = keyPairGen.generateKeyPair(); RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate(); // 得到私钥 RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic(); // 得到公钥 String publicKeyString = new String(Base64.encodeBase64(publicKey.getEncoded())); // 得到私钥字符串 String privateKeyString = new String(Base64.encodeBase64((privateKey.getEncoded()))); // 将公钥和私钥保存到 keyMap.put(0, publicKeyString); // 0表示公钥 keyMap.put(1, privateKeyString); // 1表示私钥 } public static String encrypt(String str, String publicKey) throws Exception { // base64编码的公钥 byte[] decoded = Base64.decodeBase64(publicKey); RSAPublicKey pubKey = (RSAPublicKey) KeyFactory.getInstance("RSA") .generatePublic(new X509EncodedKeySpec(decoded)); // RSA加密 Cipher cipher = Cipher.getInstance("RSA"); cipher.init(Cipher.ENCRYPT_MODE, pubKey); String outStr = Base64.encodeBase64String(cipher.doFinal(str.getBytes("UTF-8"))); return outStr; } public static String decrypt(String str, String privateKey) throws Exception { // 64位解码加密后的字符串 byte[] inputByte = Base64.decodeBase64(str.getBytes("UTF-8")); // base64编码的私钥 byte[] decoded = Base64.decodeBase64(privateKey); RSAPrivateKey priKey = (RSAPrivateKey) KeyFactory.getInstance("RSA") .generatePrivate(new PKCS8EncodedKeySpec(decoded)); // RSA解密 Cipher cipher = Cipher.getInstance("RSA"); cipher.init(Cipher.DECRYPT_MODE, priKey); String outStr = new String(cipher.doFinal(inputByte)); return outStr; } }