import java.security.SecureRandom;
import java.security.Security;
import java.util.Arrays;
import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.spec.SecretKeySpec;
import org.bouncycastle.jce.provider.BouncyCastleProvider;
import org.bouncycastle.pqc.math.linearalgebra.ByteUtils;

public class SM4Util {
    private static final String ENCODING = "UTF-8";
    private static final String ALGORITHM_NAME = "SM4";
    private static final String ALGORITHM_ECB_PKCS5PADDING = "SM4/ECB/PKCS7Padding";
    private static final int DEFAULT_KEY_SIZE = 128;

    private SM4Util() {
    }

    public static boolean verify(String cipherText, String hexKey, String paramStr) throws Exception {
        boolean flag = false;
        byte[] key = ByteUtils.fromHexString(hexKey);
        byte[] data = ByteUtils.fromHexString(cipherText);
        byte[] decryptData = decrypt(data, key);
        byte[] srcData = paramStr.getBytes("UTF-8");
        flag = Arrays.equals(decryptData, srcData);
        return flag;
    }

    public static String generateStrKey() throws Exception {
        return ByteUtils.toHexString(generateKey());
    }

    public static byte[] generateKey() throws Exception {
        KeyGenerator kg = KeyGenerator.getInstance("SM4", "BC");
        kg.init(128, new SecureRandom());
        return kg.generateKey().getEncoded();
    }

    public static String encrypt(String paramStr, String hexKey) throws Exception {
        String cipherText = "";
        if (null != paramStr && !"".equals(paramStr)) {
            byte[] key = ByteUtils.fromHexString(hexKey);
            byte[] data = paramStr.getBytes("UTF-8");
            byte[] cipherArray = encrypt(data, key);
            cipherText = ByteUtils.toHexString(cipherArray);
        }

        return cipherText;
    }

    public static byte[] encrypt(byte[] data, byte[] key) throws Exception {
        return sm4(data, key, 1);
    }

    public static String decrypt(String paramStr, String hexKey) throws Exception {
        String decryptStr = "";
        byte[] key = ByteUtils.fromHexString(hexKey);
        byte[] data = ByteUtils.fromHexString(paramStr);
        byte[] srcData = decrypt(data, key);
        decryptStr = new String(srcData, "UTF-8");
        return decryptStr;
    }

    public static byte[] decrypt(byte[] data, byte[] key) throws Exception {
        return sm4(data, key, 2);
    }

    private static byte[] sm4(byte[] input, byte[] key, int mode) throws Exception {
        SecretKeySpec sm4Key = new SecretKeySpec(key, "SM4");
        Cipher cipher = Cipher.getInstance("SM4/ECB/PKCS7Padding", "BC");
        cipher.init(mode, sm4Key);
        return cipher.doFinal(input);
    }

    static {
        if (null == Security.getProvider("BC")) {
            Security.addProvider(new BouncyCastleProvider());
        }

    }
}