【烦人的加密算法】国密 SM4 的使用--Java版本_sm4使用

和 SM2 引入的包一样， SM2 为非对称算案发，SM4 为对称算法
【烦人的加密算法】国密SM2的使用–Java版本

SM4Utils 直接可用

import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang3.StringUtils;
import org.bouncycastle.jce.provider.BouncyCastleProvider;
import org.bouncycastle.pqc.math.linearalgebra.ByteUtils;

import javax.crypto.Cipher;
import javax.crypto.CipherInputStream;
import javax.crypto.spec.SecretKeySpec;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.nio.charset.Charset;
import java.security.Key;
import java.security.Security;
import java.util.Base64;

/**
 * SM4加密算法
 *
 * @author hcf
 * @date 2021/8/31 16:51
 */
@Slf4j
public class SM4Utils {

    public static final String ALGORITHM_NAME = "SM4";
    public static final String ALGORITHM_NAME_ECB_PADDING = "SM4/ECB/PKCS7Padding";

    public SM4Utils() {
    }

    static {
        Security.addProvider(new BouncyCastleProvider());
    }

    /**
     * 加密
     *
     * @param hexKey  明文密钥
     * @param content 内容
     * @param charset 编码
     * @return 加密数据
     */
    public static String encrypt(String hexKey, String content, Charset charset) {
        String encryptContent = StringUtils.EMPTY;
        try {
            byte[] keyData = ByteUtils.fromHexString(hexKey);
            byte[] contentData = content.getBytes(charset);
            byte[] encryptData = encryptEcbPadding(keyData, contentData);
            encryptContent = Base64.getEncoder().encodeToString(encryptData);
        } catch (Exception e) {
            log.error("SM4Utils.encrypt(String hexKey, String content, String charset) error {}", e.getMessage(), e);
        }
        return encryptContent;
    }

    public static byte[] encryptEcbPadding(byte[] key, byte[] data) throws Exception {
        Cipher cipher = generateEcbCipher(Cipher.ENCRYPT_MODE, key);
        return cipher.doFinal(data);
    }

    /**
     * 解密
     *
     * @param hexKey         密钥
     * @param encryptContent 密文
     * @param charset        编码
     * @return 解密数据
     */
    public static String decrypt(String hexKey, String encryptContent, Charset charset) {

        String content = StringUtils.EMPTY;
        try {
            byte[] keyData = ByteUtils.fromHexString(hexKey);
            byte[] encryptData = Base64.getDecoder().decode(encryptContent);
            byte[] contentData = decryptEcbPadding(keyData, encryptData);
            content = new String(contentData, charset);
        } catch (Exception e) {
            log.error("SM4Utils.encrypt(String hexKey, String content, String charset) error {}", e.getMessage(), e);
        }
        return content;
    }

    private static byte[] decryptEcbPadding(byte[] key, byte[] cipherText) throws Exception {
        Cipher cipher = generateEcbCipher(Cipher.DECRYPT_MODE, key);
        return cipher.doFinal(cipherText);
    }

    private static Cipher generateEcbCipher(int mode, byte[] key) throws Exception {
        Cipher cipher = Cipher.getInstance(ALGORITHM_NAME_ECB_PADDING, BouncyCastleProvider.PROVIDER_NAME);
        Key sm4Key = new SecretKeySpec(key, ALGORITHM_NAME);
        cipher.init(mode, sm4Key);
        return cipher;
    }


    public static void main(String[] args) throws Exception {
        String hexCipher = CipherUtils.randomHexCipher();
        String encrypt = encrypt(hexCipher, "content", StandardCharsets.UTF_8);
        System.out.println(encrypt);
        System.out.println(decrypt(hexCipher, encrypt, StandardCharsets.UTF_8));
    }

}

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CipherUtils

import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang3.StringUtils;
import java.security.SecureRandom;
import java.util.Random;

/**
 * 密钥生成工具类
 *
 * @author hcf
 * @date 2021/9/1 17:44
 */
@Slf4j
public class CipherUtils {

    private static final int AES_KEY_LENGTH = 16;

    public static String randomHexCipher() {
        String cipher = randomCipher();
        StringBuilder hexCipher = new StringBuilder(StringUtils.EMPTY);
        for (int i = 0; i < cipher.length(); i++) {
            int ch = cipher.charAt(i);
            String s4 = Integer.toHexString(ch);
            hexCipher.append(s4);
        }
        return hexCipher.toString();
    }

    /**
     * 生成密钥
     *
     * @return 密钥
     */
    public static String randomCipher() {
        char[] chars = new char[AES_KEY_LENGTH];
        SecureRandom rnd = new SecureRandom();
        chars[nextIndex(chars, rnd)] = nextUpperlLetter(rnd);
        chars[nextIndex(chars, rnd)] = nextLowerLetter(rnd);
        chars[nextIndex(chars, rnd)] = nextNumLetter(rnd);
        for (int i = 0; i < chars.length; i++) {
            if (chars[i] == 0) {
                chars[i] = nextChar(rnd);
            }
        }
        return new String(chars);
    }

    private static int nextIndex(char[] chars, SecureRandom rnd) {

        int index = rnd.nextInt(chars.length);
        while (chars[index] != 0) {
            index = rnd.nextInt(chars.length);
        }
        return index;
    }

    private static char nextUpperlLetter(Random rnd) {
        return (char) ('A' + rnd.nextInt(26));
    }

    private static char nextLowerLetter(Random rnd) {
        return (char) ('a' + rnd.nextInt(26));
    }

    private static char nextNumLetter(Random rnd) {
        return (char) ('0' + rnd.nextInt(10));
    }

    private static char nextChar(SecureRandom rnd) {
        switch (rnd.nextInt(3)) {
            case 0:
                return (char) ('a' + rnd.nextInt(26));
            case 1:
                return (char) ('A' + rnd.nextInt(26));
            default:
                return (char) ('0' + rnd.nextInt(10));
        }
    }
}

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