RSA加密与解密

jdk 1.8

 

package test.mima;

import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.SecureRandom;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.Base64;

import javax.crypto.Cipher;

public class RSATest {

    public static String publicKey = "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCBaTlrnFzuBvsDNR1B+ckEslQ6/0y73wf483MB+gZZ1NRPwvasZyuk14AhDMVFRhH+B/iICa4H6MW/tTRRKMT9oMd8CFeYLfl6ik3fJCqRemBcOI4k4a3bfWvwufaxUr2KvGcUAM3zDK2J8saxQhlD9H61P9duU8wIij/RDoAwDwIDAQAB";
    public static String privateKey = "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";

    public static String text = "hello nihaoo1234  hello nihao 世界,";

    public static void main(String[] args) throws Exception {
        // TODO Auto-generated method stub

        KeyPair keyPair = genKeyPair(1024);

        publicKey = Base64.getEncoder().encodeToString(keyPair.getPublic().getEncoded());
        privateKey = Base64.getEncoder().encodeToString(keyPair.getPrivate().getEncoded());

        System.out.println("公钥：" + publicKey);
        System.out.println("私钥：" + privateKey);

        PublicKey publick = getPublicKey(publicKey);

        PrivateKey privatek = getPrivateKey(privateKey);

        String mw = encrypt(text, publick);
        System.out.println(mw);
        String mmw = decrypt(mw, privatek);
        System.out.println(mmw);
    }

    // 生成密钥对
    public static KeyPair genKeyPair(int keyLength) throws Exception {

        // 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(keyLength, new SecureRandom());
        // 生成一个密钥对，保存在keyPair中
        KeyPair keyPair = keyPairGen.generateKeyPair();

        return keyPair;
//        KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA");
//        keyPairGenerator.initialize(1024);
//        return keyPairGenerator.generateKeyPair();
    }

    // 公钥加密
    public static String encrypt(String content, PublicKey publicKey) throws Exception {
        Cipher cipher = Cipher.getInstance("RSA");// java默认"RSA"="RSA/ECB/PKCS1Padding"
        cipher.init(Cipher.ENCRYPT_MODE, publicKey);
        byte[] data = cipher.doFinal(content.getBytes());
        return Base64.getEncoder().encodeToString(data);
    }

    // 私钥解密
    public static String decrypt(String content, PrivateKey privateKey) throws Exception {
        Cipher cipher = Cipher.getInstance("RSA");
        cipher.init(Cipher.DECRYPT_MODE, privateKey);
        byte[] data = Base64.getDecoder().decode(content.getBytes());
        return new String(cipher.doFinal(data));
    }

    /**
     * String转公钥PublicKey
     * 
     * @param key
     * @return
     * @throws Exception
     */
    public static PublicKey getPublicKey(String key) throws Exception {
        byte[] keyBytes;
        keyBytes = Base64.getDecoder().decode(key);
        X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance("RSA");
        PublicKey publicKey = keyFactory.generatePublic(keySpec);
        return publicKey;
    }

    /**
     * String转私钥PrivateKey
     * 
     * @param key
     * @return
     * @throws Exception
     */
    public static PrivateKey getPrivateKey(String key) throws Exception {
        byte[] keyBytes;

        keyBytes = Base64.getDecoder().decode(key);
        PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance("RSA");
        PrivateKey privateKey = keyFactory.generatePrivate(keySpec);
        return privateKey;
    }

}