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import org.bouncycastle.jce.provider.BouncyCastleProvider;
import org.bouncycastle.pqc.math.linearalgebra.ByteUtils;
import org.bouncycastle.util.encoders.Hex;
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;
/**
* Sm4 国密算法
*
*/
public final class Sm4Utils {
static {
Security.addProvider(new BouncyCastleProvider());
}
private static final String ENCODING = "UTF-8";
public static final String ALGORITHM_NAME = "SM4";
// 加密算法/分组加密模式/分组填充方式
// PKCS5Padding-以8个字节为一组进行分组加密
// 定义分组加密模式使用：PKCS5Padding
public static final String ALGORITHM_NAME_ECB_PADDING = "SM4/ECB/PKCS5Padding";
// 128-32位16进制；256-64位16进制
public static final int DEFAULT_KEY_SIZE = 128;
/**
* 自动生成密钥
*
* @return
* @explain
*/
public static String generateKey() throws Exception {
return new String(Hex.encode(generateKey(DEFAULT_KEY_SIZE)));
}
/**
* @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暗号
*
* @param algorithmName 算法名称
* @param mode 模式
* @param key
* @return
* @throws Exception
* @explain ECB模式（电子密码本模式：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进制密钥（忽略大小写）
* @param paramStr 待加密字符串
* @return 返回16进制的加密字符串
* @explain 加密模式：ECB
* 密文长度不固定，会随着被加密字符串长度的变化而变化
*/
public static String encryptEcb(String hexKey, String paramStr) {
try {
String cipherText = "";
// 16进制字符串-->byte[]
byte[] keyData = ByteUtils.fromHexString(hexKey);
// String-->byte[]
byte[] srcData = paramStr.getBytes(ENCODING);
// 加密后的数组
byte[] cipherArray = encryptEcbPadding(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[] encryptEcbPadding(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进制密钥
* @param cipherText 16进制的加密字符串（忽略大小写）
* @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) {
// 用于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 = decryptEcbPadding(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[] decryptEcbPadding(byte[] key, byte[] cipherText) throws Exception {
Cipher cipher = generateEcbCipher(ALGORITHM_NAME_ECB_PADDING, Cipher.DECRYPT_MODE, key);
return cipher.doFinal(cipherText);
}
/**
* 校验加密前后的字符串是否为同一数据
*
* @param hexKey 16进制密钥（忽略大小写）
* @param cipherText 16进制加密后的字符串
* @param paramStr 加密前的字符串
* @return 是否为同一数据
* @throws Exception
* @explain
*/
public static boolean verifyEcb(String hexKey, String cipherText, String paramStr) throws Exception {
// 用于接收校验结果
boolean flag = false;
// hexString-->byte[]
byte[] keyData = ByteUtils.fromHexString(hexKey);
// 将16进制字符串转换成数组
byte[] cipherData = ByteUtils.fromHexString(cipherText);
// 解密
byte[] decryptData = decryptEcbPadding(keyData, cipherData);
// 将原字符串转换成byte[]
byte[] srcData = paramStr.getBytes(ENCODING);
// 判断2个数组是否一致
flag = Arrays.equals(decryptData, srcData);
return flag;
}
public static void main(String[] args) {
try {
String paramStr = "Hello, world";
System.out.println("==========加密前源数据==========");
System.out.println(paramStr);
// 生成32位16进制密钥
String key = Sm4Utils.generateKey();
System.out.println("==========生成key==========");
System.out.println(key);
String cipher = Sm4Utils.encryptEcb(key, paramStr);
System.out.println("==========加密串==========");
System.out.println(cipher);
System.out.println("==========是否为同一数据==========");
System.out.println(Sm4Utils.verifyEcb(key, cipher, paramStr));
paramStr = Sm4Utils.decryptEcb(key, cipher);
System.out.println("==========解密后数据==========");
System.out.println(paramStr);
} catch (Exception e) {
e.printStackTrace();
}
}
}
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