国密4 SM4/CBC/PKCS5Padding 加密工具

import java.security.Key;
import java.security.Security;

import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;

import org.bouncycastle.jce.provider.BouncyCastleProvider;

public class Sm4Util {

 public static final String ALGORITHM_NAME = "SM4";
    public static final String ALGORITHM_NAME_CBC_PADDING = "SM4/CBC/PKCS5Padding";
    //加密的key值->自己定义
    public static final String key = "huangzy_yinnanxun";

    //必须有本静态库,否则会报错 
    //java.security.NoSuchProviderException: no such provider: BC
    static{
        try{
            Security.addProvider(new BouncyCastleProvider());
        }catch(Exception e){
            e.printStackTrace();
        }
    }

     
    public static byte[] encryptCBC(byte[] key, byte[] data) {
        try {
            Cipher cipher = generateCBCCipher(ALGORITHM_NAME_CBC_PADDING, Cipher.ENCRYPT_MODE, key);
            return cipher.doFinal(data);
        }
        catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }


    
    public static byte[] decryptCBC(byte[] key, byte[] cipherText) {
        try {
            Cipher cipher = generateCBCCipher(ALGORITHM_NAME_CBC_PADDING, Cipher.DECRYPT_MODE, key);
            //Cipher cipher = generateCBCCipher("SM4/CBC/NoPadding", Cipher.DECRYPT_MODE, key);
            return cipher.doFinal(cipherText);
        }
        catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

    private static Cipher generateCBCCipher(String algorithmName, int mode, byte[] key) {
        try {
            Cipher cipher = Cipher.getInstance(algorithmName, BouncyCastleProvider.PROVIDER_NAME);
            Key sm4Key = new SecretKeySpec(key, ALGORITHM_NAME);
            IvParameterSpec ivParameterSpec = new IvParameterSpec(new byte[16]);
            cipher.init(mode, sm4Key, ivParameterSpec);
            return cipher;
        }
        catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

    private static final char HexCharArr[] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D',
            'E', 'F' };

    public static String byteArrToHex(byte[] content) {
        char[] strArr = new char[content.length * 2];
        int i = 0;
        for (byte bt : content) {
            strArr[i++] = HexCharArr[bt >>> 4 & 0xf];
            strArr[i++] = HexCharArr[bt & 0xf];
        }
        return new String(strArr);

    }

    
    public static byte[] hexString2Bytes(String content) {
        int l = content.length() / 2;
        byte[] result = new byte[l];
        for (int i = 0; i < l; i++) {
            result[i] = Integer.valueOf(content.substring(i * 2, i * 2 + 2), 16).byteValue();
        }
        return result;
    }

    
    public static String sm4Decode(String content) {
        byte[] bytes2 = hexString2Bytes(content);
        byte[] deBytes = decryptCBC(key.getBytes(),bytes2);
        return new String(deBytes);
    }

    
    
    public static void main(String[] args) {
        System.out.println("开始测试SM4加密解密====================");
        String json = "123";
        System.out.println("加密前：" + json);
        byte[] bytes = encryptCBC(key.getBytes(), json.getBytes());
        String s = byteArrToHex(bytes).toLowerCase();
        System.out.println("加密后：" + s);

        System.out.println("解密后：" +sm4Decode(s));

    }
    

}