Generation and verification of JAVA RSA key pair-javaTutorial-php.cn

Generation and verification of JAVA RSA key pair

巴扎黑

Release： 2016-11-26 09:15:33

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In the previous article "Java&keytool generates RSA keys", we used keytool to generate the keystore and public key certificate, and then obtained the public-private key pair in the form of files and BASE64 strings through code. In fact, it is not that complicated at all. The public and private key pairs can be obtained directly through JAVA code. The code is as follows:

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);
    }
}

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