java国密加密解密

Java国密加密解密实现流程

1. 整体流程表格

步骤	描述
步骤1	准备工作，导入相关依赖
步骤2	生成密钥对
步骤3	加密明文
步骤4	解密密文

2. 步骤详解及代码实现

步骤1：准备工作，导入相关依赖

首先，我们需要在项目中引入Bouncy Castle库，该库提供了Java国密的实现。在项目的pom.xml文件中添加以下依赖：

<dependency>
    <groupId>org.bouncycastle</groupId>
    <artifactId>bcpkix-jdk15on</artifactId>
    <version>1.68</version>
</dependency>

步骤2：生成密钥对

在Java国密加密解密中，我们需要生成公钥和私钥。下面是生成密钥对的代码：

import org.bouncycastle.jce.provider.BouncyCastleProvider;

import java.math.BigInteger;
import java.security.*;
import java.security.spec.ECGenParameterSpec;

public class SM2KeyGenerator {

    public static void main(String[] args) throws NoSuchProviderException, NoSuchAlgorithmException, InvalidAlgorithmParameterException {
        Security.addProvider(new BouncyCastleProvider());

        KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("EC", "BC");
        ECGenParameterSpec sm2Spec = new ECGenParameterSpec("sm2p256v1");
        keyPairGenerator.initialize(sm2Spec, new SecureRandom());
        KeyPair keyPair = keyPairGenerator.generateKeyPair();

        PublicKey publicKey = keyPair.getPublic();
        PrivateKey privateKey = keyPair.getPrivate();

        System.out.println("公钥: " + toHexString(publicKey.getEncoded()));
        System.out.println("私钥: " + toHexString(privateKey.getEncoded()));
    }

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

上述代码通过调用Bouncy Castle提供的KeyPairGenerator来生成密钥对，其中ECGenParameterSpec("sm2p256v1")指定了使用SM2椭圆曲线生成密钥对。生成的公钥和私钥均为字节数组，通过toHexString方法将其转换为字符串形式并输出。

步骤3：加密明文

加密明文使用SM2算法，下面是加密明文的代码：

import org.bouncycastle.crypto.CipherParameters;
import org.bouncycastle.crypto.InvalidCipherTextException;
import org.bouncycastle.crypto.engines.SM2Engine;
import org.bouncycastle.crypto.params.ECPrivateKeyParameters;
import org.bouncycastle.crypto.params.ECPublicKeyParameters;
import org.bouncycastle.crypto.params.ParametersWithRandom;
import org.bouncycastle.crypto.util.PrivateKeyFactory;
import org.bouncycastle.crypto.util.PublicKeyFactory;
import org.bouncycastle.jce.provider.BouncyCastleProvider;

import java.io.IOException;
import java.security.*;
import java.security.spec.InvalidKeySpecException;

public class SM2Encryption {

    public static void main(String[] args) throws NoSuchProviderException, NoSuchAlgorithmException, InvalidKeySpecException, IOException, InvalidCipherTextException {
        Security.addProvider(new BouncyCastleProvider());

        // 明文
        String plaintext = "Hello, World!";
        byte[] plaintextBytes = plaintext.getBytes();

        // 密钥
        String publicKeyHex = "0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef";
        String privateKeyHex = "0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef";
        PublicKey publicKey = PublicKeyFactory.createKey(hexStringToByteArray(publicKeyHex));
        PrivateKey privateKey = PrivateKeyFactory.createKey(hexStringToByteArray(privateKeyHex));

        // 加密
        CipherParameters publicKeyParams = new ECPublicKeyParameters(((ECPublicKey) publicKey).getQ(), SM2Utils.DOMAIN_PARAMS);
        CipherParameters privateKeyParams = new ECPrivateKeyParameters(((ECPrivateKey) privateKey).getD(), SM2Utils.DOMAIN_PARAMS);
        CipherParameters params = new ParametersWithRandom(publicKeyParams, new SecureRandom());
        SM2Engine engine = new SM2Engine();
        engine.init(true, params);
        byte[] ciphertextBytes = engine.processBlock(plaintextBytes, 0, plaintextBytes.length);

        System.out.println("密文: " + toHexString(ciphertextBytes));
    }

    private static byte[] hexStringToByteArray(String hexString) {
        byte[] result = new byte[hexString.length