04_RSA非对称加密

/**
 * <p>Description: RSA 非对称加密</p>
 *
 * @author XXX
 * @date 2020/12/14 21:33
 * @since JDK1.8
 */
public class RSADemo {
    private static Base64.Encoder encoder = Base64.getEncoder();
    private static Base64.Decoder decoder = Base64.getDecoder();
    private static final String RSA = "RSA";

    public static void main(String[] args) throws Exception {
        //创建秘钥对
        //KeyPairGenerator 秘钥对生成器对象
        KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance(RSA);

        //生成秘钥对
        KeyPair keyPair = keyPairGenerator.generateKeyPair();

        //生成公钥
        PrivateKey privateKey = keyPair.getPrivate();
        //生成私钥
        PublicKey publicKey = keyPair.getPublic();

        //获取字节数组
        byte[] privateKeyEncoded = privateKey.getEncoded();
        byte[] publicKeyEncoded = publicKey.getEncoded();

        String privateKeyString = new String(encoder.encode(privateKeyEncoded));
        String publicKeyString = new String(encoder.encode(publicKeyEncoded));

//        System.out.println("privateKeyString-----------" + privateKeyString);
//        System.out.println("publicKeyString-----------" + publicKeyString);


        Cipher cipher = Cipher.getInstance(RSA);
        //使用私钥进行加密
        cipher.init(Cipher.ENCRYPT_MODE,privateKey);
        byte[] bytes = cipher.doFinal("哈哈".getBytes());
        String encrypt = new String(encoder.encode(bytes));
        System.out.println(encrypt);

        //使用公钥解密
        cipher.init(Cipher.DECRYPT_MODE,publicKey);
        byte[] decrypt = cipher.doFinal(bytes);
        System.out.println(new String(decrypt));
        
        //根据**对生成Key
        KeyFactory keyFactory = KeyFactory.getInstance(RSA);

        PKCS8EncodedKeySpec privateKeySpec = new PKCS8EncodedKeySpec(decoder.decode(privateKeyString));
        PrivateKey privateKey2 = keyFactory.generatePrivate(privateKeySpec);

        X509EncodedKeySpec publicKeySpec = new X509EncodedKeySpec(decoder.decode(publicKeyString));
        PublicKey publicKey2 = keyFactory.generatePublic(publicKeySpec);




        //加密模式和填充模式 默认 RSA/ECB/PKCS5Padding
        Cipher c = Cipher.getInstance("RSA/CBC/PKCS5Padding");

        //CBC的情况下， 加密需要iv向量 key.getBytes()
        IvParameterSpec iv = new IvParameterSpec("key".getBytes());
        SecretKeySpec keySpec = new SecretKeySpec("key".getBytes(), "DES");
        c.init(Cipher.ENCRYPT_MODE, keySpec, iv);

        //解密也需要向量
        cipher.init(Cipher.DECRYPT_MODE, keySpec,iv);
    }

}