SM4國密算法java實現

import org.apache.commons.codec.binary.Hex;
import org.bouncycastle.jce.provider.BouncyCastleProvider;
import org.bouncycastle.pqc.math.linearalgebra.ByteUtils;

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.spec.SecretKeySpec;
import java.security.Key;
import java.security.SecureRandom;
import java.security.Security;
import java.util.Arrays;

public class Sm4Util {
    static {
        Security.addProvider(new BouncyCastleProvider());
    }
    
    private static final String ENCODING = "UTF-8";
    public static final String ALGORITHM_NAME = "SM4";
    // 加密算法/分組加密模式/分組填充方式
    // PKCS5Padding-以8個字節為一組進行分組加密
    // 定義分組加密模式使用：PKCS5Padding
    public static final String ALGORITHM_NAME_ECB_PADDING = "SM4/ECB/PKCS5Padding";
    // 128-32位16進制；256-64位16進制
    public static final int DEFAULT_KEY_SIZE = 128;
    
    /**
     * 自動生成密鑰
     *
     * @return
     * @explain
     */
    public static String generateKey() throws Exception {
        return new String(Hex.encodeHex(generateKey(DEFAULT_KEY_SIZE),false));
    }
    
    /**
     * @param keySize
     * @return
     * @throws Exception
     * @explain
     */
    public static byte[] generateKey(int keySize) throws Exception {
        KeyGenerator kg = KeyGenerator.getInstance(ALGORITHM_NAME, BouncyCastleProvider.PROVIDER_NAME);
        kg.init(keySize, new SecureRandom());
        return kg.generateKey().getEncoded();
    }
    
    /**
     * 生成ECB暗號
     *
     * @param algorithmName 算法名稱
     * @param mode          模式
     * @param key
     * @return
     * @throws Exception
     * @explain ECB模式（電子密碼本模式：Electronic codebook）
     */
    private static Cipher generateEcbCipher(String algorithmName, int mode, byte[] key) throws Exception {
        Cipher cipher = Cipher.getInstance(algorithmName, BouncyCastleProvider.PROVIDER_NAME);
        Key sm4Key = new SecretKeySpec(key, ALGORITHM_NAME);
        cipher.init(mode, sm4Key);
        return cipher;
    }
    
    /**
     * sm4加密
     *
     * @param hexKey   16進制密鑰（忽略大小寫）
     * @param paramStr 待加密字符串
     * @return 返回16進制的加密字符串
     * @explain 加密模式：ECB
     * 密文長度不固定，會隨着被加密字符串長度的變化而變化
     */
    public static String encryptEcb(String hexKey, String paramStr) {
        try {
            String cipherText = "";
            // 16進制字符串-->byte[]
            byte[] keyData = ByteUtils.fromHexString(hexKey);
            // String-->byte[]
            byte[] srcData = paramStr.getBytes(ENCODING);
            // 加密后的數組
            byte[] cipherArray = encrypt_Ecb_Padding(keyData, srcData);
            // byte[]-->hexString
            cipherText = ByteUtils.toHexString(cipherArray);
            return cipherText;
        } catch (Exception e) {
            return paramStr;
        }
    }
    
    /**
     * 加密模式之Ecb
     *
     * @param key
     * @param data
     * @return
     * @throws Exception
     * @explain
     */
    public static byte[] encrypt_Ecb_Padding(byte[] key, byte[] data) throws Exception {
        Cipher cipher = generateEcbCipher(ALGORITHM_NAME_ECB_PADDING, Cipher.ENCRYPT_MODE, key);
        return cipher.doFinal(data);
    }
    
    /**
     * sm4解密
     *
     * @param hexKey     16進制密鑰
     * @param cipherText 16進制的加密字符串（忽略大小寫）
     * @return 解密后的字符串
     * @throws Exception
     * @explain 解密模式：采用ECB
     */
    public static String decryptEcb(String hexKey, String cipherText) {
        // 用於接收解密后的字符串
        String decryptStr = "";
        // hexString-->byte[]
        byte[] keyData = ByteUtils.fromHexString(hexKey);
        // hexString-->byte[]
        byte[] cipherData = ByteUtils.fromHexString(cipherText);
        // 解密
        byte[] srcData = new byte[0];
        try {
            srcData = decrypt_Ecb_Padding(keyData, cipherData);
            // byte[]-->String
            decryptStr = new String(srcData, ENCODING);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return decryptStr;
    }
    
    /**
     * 解密
     *
     * @param key
     * @param cipherText
     * @return
     * @throws Exception
     * @explain
     */
    public static byte[] decrypt_Ecb_Padding(byte[] key, byte[] cipherText) throws Exception {
        Cipher cipher = generateEcbCipher(ALGORITHM_NAME_ECB_PADDING, Cipher.DECRYPT_MODE, key);
        return cipher.doFinal(cipherText);
    }
    
    /**
     * 校驗加密前后的字符串是否為同一數據
     *
     * @param hexKey     16進制密鑰（忽略大小寫）
     * @param cipherText 16進制加密后的字符串
     * @param paramStr   加密前的字符串
     * @return 是否為同一數據
     * @throws Exception
     * @explain
     */
    public static boolean verifyEcb(String hexKey, String cipherText, String paramStr) throws Exception {
        // 用於接收校驗結果
        boolean flag = false;
        // hexString-->byte[]
        byte[] keyData = ByteUtils.fromHexString(hexKey);
        // 將16進制字符串轉換成數組
        byte[] cipherData = ByteUtils.fromHexString(cipherText);
        // 解密
        byte[] decryptData = decrypt_Ecb_Padding(keyData, cipherData);
        // 將原字符串轉換成byte[]
        byte[] srcData = paramStr.getBytes(ENCODING);
        // 判斷2個數組是否一致
        flag = Arrays.equals(decryptData, srcData);
        return flag;
    }
    
    public static void main(String[] args) {
        try {
            String json = "BF7B6BD7C1204BC4F3C87D235692DE9DBF7B6BD7C1204BC4F3C87D235692DE9DBF7B6BD7C1204BC4F3C87D235692DE9D";
            System.out.println("加密前源數據————" + json);
            // 生成32位16進制密鑰
            String key = Sm4Util.generateKey();
            System.out.println(key + "-----生成key");
            String cipher = Sm4Util.encryptEcb(key, json);
            System.out.println("加密串---" + cipher);
            System.out.println(Sm4Util.verifyEcb(key, cipher, json));
            json = Sm4Util.decryptEcb(key, cipher);
            System.out.println("解密后數據---" + json);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}