Java生成密钥的实例.zip

/* * Copyright (c) 2004 ???. All Rights Reserved. * Download by http://www.codefans.net * Version 1.0 , Created on 2004-3-10 * */ /** * @author Devon */ /** * 如何产生和保存密钥 */ import java.security.*; import java.security.spec.*; import javax.crypto.*; import java.io.*; public class KeyGeneratorExample { public static void main(String[] args) { try{ //产生单钥加密的密钥(myKey) KeyGenerator keyGenerator = KeyGenerator.getInstance("DESede"); //采用DESede算法 keyGenerator.init(168); //选择DESede算法,密钥长度为112位或168位 Key myKey = keyGenerator.generateKey(); //生成密钥 System.out.println("得到单钥加密密钥"); //产生双钥的密钥对(keyPair) KeyPairGenerator keyPairGenerator=KeyPairGenerator.getInstance("RSA"); //采用RSA算法 keyPairGenerator.initialize(1024); //指定密钥长度为1024位 KeyPair keyPair = keyPairGenerator.generateKeyPair(); //生成密钥对 System.out.println("生成张三的公钥对"); //保存公钥的字节数组 File f = new File("publicKey.dat"); //保存公钥到文件publicKey.dat FileOutputStream fout = new FileOutputStream(f); fout.write(keyPair.getPublic().getEncoded()); //得到公钥的字节数组 fout.close(); //关闭文件输出流 System.out.println("保存公钥到文件: "+f.getAbsolutePath()); //用Java对象序列化保存私钥,通常应对私钥加密后再保存 ObjectOutputStream oout = new ObjectOutputStream(new FileOutputStream("privateKey.dat")); //保存私钥到文件privateKey.dat oout.writeObject(keyPair.getPrivate()); //序列化私钥 oout.close(); //关闭输出流 System.err.println("保存私钥到: privateKey.dat"); //从文件中得到公钥编码的字节数组 FileInputStream fin = new FileInputStream("publicKey.dat"); //打天publicKey.dat ByteArrayOutputStream baout = new ByteArrayOutputStream(); //用于写入文件的字节流 int aByte = 0; while ((aByte = fin.read())!= -1) //从文件读取一个字节 { baout.write(aByte); //写入一个字节 } fin.close(); //关闭文件输入流 byte[] keyBytes = baout.toByteArray(); //得到公钥的字节数组 baout.close(); //关闭字节数组输出流 //从字节数组解码公钥 X509EncodedKeySpec x509KeySpec =new X509EncodedKeySpec(keyBytes); KeyFactory keyFactory = KeyFactory.getInstance("RSA"); //指定算法RSA,得到一个KeyFactory的实例 PublicKey pubKey = keyFactory.generatePublic(x509KeySpec); //解码公钥 System.out.println("从文件中成功得到公钥"); }catch (Exception ex){ex.printStackTrace(); } } }