sm4加密算法java代码

SM4（Stream cipher Mode with 4 keys）是一种中国自主研发的块密码，它属于SM系列，主要用于对数据流进行加密。在Java中，如果你想要使用SM4加密算法，你需要依赖于一些第三方库，如BCryptor或JSSE（Java Security Extension），因为Java标准库本身并未直接提供SM4的支持。

以下是一个简单的使用BCryptor库实现SM4加密的例子：

import org.bouncycastle.jce.provider.BouncyCastleProvider;
import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;

public class SM4Example {
    static {
        // 注册BouncyCastle Provider
        try {
            Security.addProvider(new BouncyCastleProvider());
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    private static final String SM4_ALGORITHM = "AES/SM4/NoPadding";

    public static String encrypt(String key, String iv, String plainText) {
        try {
            byte[] keyBytes = key.getBytes("UTF-8");
            byte[] ivBytes = iv.getBytes("UTF-8");

            Cipher cipher = Cipher.getInstance(SM4_ALGORITHM, "BC");
            cipher.init(Cipher.ENCRYPT_MODE, new SecretKeySpec(keyBytes, "AES"), new IvParameterSpec(ivBytes));

            byte[] encrypted = cipher.doFinal(plainText.getBytes("UTF-8"));
            return bytesToHex(encrypted);
        } catch (Exception e) {
            throw new RuntimeException("Failed to encrypt", e);
        }
    }

    private static String decrypt(String key, String iv, String cipherText) {
        // 解密过程类似，只是cipher.init()中的Cipher.ENCRYPT_MODE改为Cipher.DECRYPT_MODE
        // 并用相同的key和iv
        // ...
    }

    private static String bytesToHex(byte[] bytes) {
        StringBuilder hex = new StringBuilder();
        for (byte b : bytes) {
            hex.append(String.format("%02x", b));
        }
        return hex.toString();
    }

    // 使用示例
    public static void main(String[] args) {
        String key = "your_secret_key";
        String iv = "your_initialization_vector";
        String plainText = "Hello, World!";
        String encrypted = encrypt(key, iv, plainText);
        System.out.println("Encrypted: " + encrypted);
        // 更多处理...
    }
}