package chapter12Hash;

import org.bouncycastle.jce.provider.BouncyCastleProvider;

import javax.crypto.*;
import javax.crypto.spec.*;
import java.math.BigInteger;
import java.security.GeneralSecurityException;
import java.security.SecureRandom;
import java.security.Security;
import java.util.Base64;

public class EncryptDemo3PBE {
    public static void main(String[] args) throws Exception{

        Security.addProvider( new BouncyCastleProvider()); // 把BouncyCastle作为Provider添加到java.security:
        String message = "Hello World!"; //原文
        String password = "hello12345"; //加密口令
        byte[] salt = SecureRandom.getInstanceStrong().generateSeed(16);
        System.out.printf("salt: %032x\n", new BigInteger(1, salt));

        // 加密:
        byte[] data = message.getBytes("UTF-8");
        byte[] encrypted = encrypt(password, salt, data);
        System.out.println("encrypted: " + Base64.getEncoder().encodeToString(encrypted));
        // 解密:
        byte[] decrypted = decrypt(password, salt, encrypted);
        System.out.println("decrypted: " + new String(decrypted, "UTF-8"));
    }

    // 加密
    public static byte[] encrypt(String password, byte[] salt, byte[] input) throws GeneralSecurityException {
        PBEKeySpec keySpec = new PBEKeySpec(password.toCharArray());
        SecretKeyFactory secretKeyFactory = SecretKeyFactory.getInstance("PBEwithSHA1and128bitAES-CBC-BC");
        SecretKey skey = secretKeyFactory.generateSecret(keySpec);
        PBEParameterSpec pbeps = new PBEParameterSpec(salt, 1000);
        Cipher cipher = Cipher.getInstance("PBEwithSHA1and128bitAES-CBC-BC");
        cipher.init(Cipher.ENCRYPT_MODE, skey, pbeps);
        return cipher.doFinal(input);
    }


    // 解密:
    public static byte[] decrypt(String password, byte[] salt, byte[] input) throws GeneralSecurityException {
        PBEKeySpec keySpec = new PBEKeySpec(password.toCharArray());
        SecretKeyFactory skeyFactory = SecretKeyFactory.getInstance("PBEwithSHA1and128bitAES-CBC-BC");
        SecretKey skey = skeyFactory.generateSecret(keySpec);
        PBEParameterSpec pbeps = new PBEParameterSpec(salt, 1000);
        Cipher cipher = Cipher.getInstance("PBEwithSHA1and128bitAES-CBC-BC");
        cipher.init(Cipher.DECRYPT_MODE, skey, pbeps);
        return cipher.doFinal(input);
    }
}