package com.bijian.test;
import java.io.FileOutputStream;
import java.io.ObjectOutputStream;
import java.security.Key;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import sun.misc.BASE64Encoder;
public class KeyPairGenUtil {
    /** 指定加密算法为RSA */
    private static final String ALGORITHM = "RSA";
    /** 密钥长度，用来初始化 */
    private static final int KEYSIZE = 1024;
    /** 指定公钥存放文件 */
    private static String PUBLIC_KEY_FILE = "PublicKey";
    /** 指定私钥存放文件 */
    private static String PRIVATE_KEY_FILE = "PrivateKey";
    public static void main(String[] args) throws Exception {
        generateKeyPair();
        genKeyPair();
    }
    /**
    * 生成密钥对
    * @throws Exception
    */
    private static void generateKeyPair() throws Exception {
        //     /** RSA算法要求有一个可信任的随机数源 */
        //     SecureRandom secureRandom = new SecureRandom();
        /** 为RSA算法创建一个KeyPairGenerator对象 */
        KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance(ALGORITHM);
        /** 利用上面的随机数据源初始化这个KeyPairGenerator对象 */
        //     keyPairGenerator.initialize(KEYSIZE, secureRandom);
        keyPairGenerator.initialize(KEYSIZE);
        /** 生成密匙对 */
        KeyPair keyPair = keyPairGenerator.generateKeyPair();
        /** 得到公钥 */
        Key publicKey = keyPair.getPublic();
        /** 得到私钥 */
        Key privateKey = keyPair.getPrivate();
        ObjectOutputStream oos1 = null;
        ObjectOutputStream oos2 = null;
        try {
            /** 用对象流将生成的密钥写入文件 */
            oos1 = new ObjectOutputStream(new FileOutputStream(PUBLIC_KEY_FILE));
            oos2 = new ObjectOutputStream(new FileOutputStream(PRIVATE_KEY_FILE));
            oos1.writeObject(publicKey);
            oos2.writeObject(privateKey);
        } catch (Exception e) {
            throw e;
        } finally {
            /** 清空缓存，关闭文件输出流 */
            oos1.close();
            oos2.close();
        }
    }
    private static void genKeyPair() throws NoSuchAlgorithmException {
        
        /** RSA算法要求有一个可信任的随机数源 */
        SecureRandom secureRandom = new SecureRandom();
        
        /** 为RSA算法创建一个KeyPairGenerator对象 */
        KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance(ALGORITHM);
        /** 利用上面的随机数据源初始化这个KeyPairGenerator对象 */
        keyPairGenerator.initialize(KEYSIZE, secureRandom);
        //keyPairGenerator.initialize(KEYSIZE);
        /** 生成密匙对 */
        KeyPair keyPair = keyPairGenerator.generateKeyPair();
        /** 得到公钥 */
        Key publicKey = keyPair.getPublic();
        /** 得到私钥 */
        Key privateKey = keyPair.getPrivate();
        byte[] publicKeyBytes = publicKey.getEncoded();
        byte[] privateKeyBytes = privateKey.getEncoded();
        String publicKeyBase64 = new BASE64Encoder().encode(publicKeyBytes);
        String privateKeyBase64 = new BASE64Encoder().encode(privateKeyBytes);
        System.out.println("publicKeyBase64.length():" + publicKeyBase64.length());
        System.out.println("publicKeyBase64:" + publicKeyBase64);
        System.out.println("privateKeyBase64.length():" + privateKeyBase64.length());
        System.out.println("privateKeyBase64:" + privateKeyBase64);
    }
}