package minsecurity.crypto;

import org.bouncycastle.jce.provider.BouncyCastleProvider;

import javax.crypto.*;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import java.security.*;

/*
 * @Author: hongyu guo
 * @Description: sm4算法
 * @Version: 1.0.0
 * @Date: 16:26 2021/03/04
 * @Copyright: MIN-Group；国家重大科技基础设施——未来网络北大实验室；深圳市信息论与未来网络重点实验室
 */
public class SM4 {
    static {
        Security.addProvider(new org.bouncycastle.jce.provider.BouncyCastleProvider());
    }
    public static final String ALGORITHM_NAME = "SM4";
    public static final String ALGORITHM_NAME_ECB_PADDING = "SM4/ECB/PKCS5Padding";
    public static final String ALGORITHM_NAME_ECB_NOPADDING = "SM4/ECB/NoPadding";
    public static final String ALGORITHM_NAME_CBC_PADDING = "SM4/CBC/PKCS5Padding";
    public static final String ALGORITHM_NAME_CBC_NOPADDING = "SM4/CBC/NoPadding";

    /**
     * SM4算法目前只支持128位（即密钥16字节）
     */
    public static final int DEFAULT_KEY_SIZE = 128;

    public static byte[] generateKey() throws NoSuchAlgorithmException, NoSuchProviderException {
        return generateKey(DEFAULT_KEY_SIZE);
    }

    public static byte[] generateKey(int keySize) throws NoSuchAlgorithmException, NoSuchProviderException {
        KeyGenerator kg = KeyGenerator.getInstance(ALGORITHM_NAME, BouncyCastleProvider.PROVIDER_NAME);
        kg.init(keySize, new SecureRandom());
        return kg.generateKey().getEncoded();
    }

    public static byte[] encrypt_ECB_Padding(byte[] key, byte[] data)
            throws InvalidKeyException, NoSuchAlgorithmException, NoSuchProviderException,
            NoSuchPaddingException, IllegalBlockSizeException, BadPaddingException {
        Cipher cipher = generateECBCipher(ALGORITHM_NAME_ECB_PADDING, Cipher.ENCRYPT_MODE, key);
        return cipher.doFinal(data);
    }

    public static byte[] decrypt_ECB_Padding(byte[] key, byte[] cipherText)
            throws IllegalBlockSizeException, BadPaddingException, InvalidKeyException,
            NoSuchAlgorithmException, NoSuchProviderException, NoSuchPaddingException {
        Cipher cipher = generateECBCipher(ALGORITHM_NAME_ECB_PADDING, Cipher.DECRYPT_MODE, key);
        return cipher.doFinal(cipherText);
    }

    public static byte[] encrypt_ECB_NoPadding(byte[] key, byte[] data)
            throws InvalidKeyException, NoSuchAlgorithmException, NoSuchProviderException,
            NoSuchPaddingException, IllegalBlockSizeException, BadPaddingException {
        Cipher cipher = generateECBCipher(ALGORITHM_NAME_ECB_NOPADDING, Cipher.ENCRYPT_MODE, key);
        return cipher.doFinal(data);
    }

    public static byte[] decrypt_ECB_NoPadding(byte[] key, byte[] cipherText)
            throws IllegalBlockSizeException, BadPaddingException, InvalidKeyException,
            NoSuchAlgorithmException, NoSuchProviderException, NoSuchPaddingException {
        Cipher cipher = generateECBCipher(ALGORITHM_NAME_ECB_NOPADDING, Cipher.DECRYPT_MODE, key);
        return cipher.doFinal(cipherText);
    }

    public static byte[] encrypt_CBC_Padding(byte[] key, byte[] iv, byte[] data)
            throws InvalidKeyException, NoSuchAlgorithmException, NoSuchProviderException,
            NoSuchPaddingException, IllegalBlockSizeException, BadPaddingException,
            InvalidAlgorithmParameterException {
        Cipher cipher = generateCBCCipher(ALGORITHM_NAME_CBC_PADDING, Cipher.ENCRYPT_MODE, key, iv);
        return cipher.doFinal(data);
    }

    public static byte[] decrypt_CBC_Padding(byte[] key, byte[] iv, byte[] cipherText)
            throws IllegalBlockSizeException, BadPaddingException, InvalidKeyException,
            NoSuchAlgorithmException, NoSuchProviderException, NoSuchPaddingException,
            InvalidAlgorithmParameterException {
        Cipher cipher = generateCBCCipher(ALGORITHM_NAME_CBC_PADDING, Cipher.DECRYPT_MODE, key, iv);
        return cipher.doFinal(cipherText);
    }

    public static byte[] encrypt_CBC_NoPadding(byte[] key, byte[] iv, byte[] data)
            throws InvalidKeyException, NoSuchAlgorithmException, NoSuchProviderException,
            NoSuchPaddingException, IllegalBlockSizeException, BadPaddingException,
            InvalidAlgorithmParameterException {
        Cipher cipher = generateCBCCipher(ALGORITHM_NAME_CBC_NOPADDING, Cipher.ENCRYPT_MODE, key, iv);
        return cipher.doFinal(data);
    }

    public static byte[] decrypt_CBC_NoPadding(byte[] key, byte[] iv, byte[] cipherText)
            throws IllegalBlockSizeException, BadPaddingException, InvalidKeyException,
            NoSuchAlgorithmException, NoSuchProviderException, NoSuchPaddingException,
            InvalidAlgorithmParameterException {
        Cipher cipher = generateCBCCipher(ALGORITHM_NAME_CBC_NOPADDING, Cipher.DECRYPT_MODE, key, iv);
        return cipher.doFinal(cipherText);
    }

    private static Cipher generateECBCipher(String algorithmName, int mode, byte[] key)
            throws NoSuchAlgorithmException, NoSuchProviderException, NoSuchPaddingException,
            InvalidKeyException {
        Cipher cipher = Cipher.getInstance(algorithmName, BouncyCastleProvider.PROVIDER_NAME);
        Key sm4Key = new SecretKeySpec(key, ALGORITHM_NAME);
        cipher.init(mode, sm4Key);
        return cipher;
    }

    private static Cipher generateCBCCipher(String algorithmName, int mode, byte[] key, byte[] iv)
            throws InvalidKeyException, InvalidAlgorithmParameterException, NoSuchAlgorithmException,
            NoSuchProviderException, NoSuchPaddingException {
        Cipher cipher = Cipher.getInstance(algorithmName, BouncyCastleProvider.PROVIDER_NAME);
        Key sm4Key = new SecretKeySpec(key, ALGORITHM_NAME);
        IvParameterSpec ivParameterSpec = new IvParameterSpec(iv);
        cipher.init(mode, sm4Key, ivParameterSpec);
        return cipher;
    }
}