Java를 사용하여 RSA 암호화 알고리즘을 구현하는 방법

import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.NoSuchAlgorithmException;

public class RSAKeyGenerator {
    public static void main(String[] args) {
        try {
            // 创建RSA密钥对生成器
            KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA");
            // 初始化密钥长度为2048位
            keyPairGenerator.initialize(2048);
            // 生成密钥对
            KeyPair keyPair = keyPairGenerator.generateKeyPair();
            // 获取公钥
            String publicKey = Base64.getEncoder().encodeToString(keyPair.getPublic().getEncoded());
            System.out.println("公钥：" + publicKey);
            // 获取私钥
            String privateKey = Base64.getEncoder().encodeToString(keyPair.getPrivate().getEncoded());
            System.out.println("私钥：" + privateKey);
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        }
    }
}

import javax.crypto.Cipher;
import java.security.KeyFactory;
import java.security.PublicKey;
import java.security.spec.X509EncodedKeySpec;

public class RSAEncryptor {
    public static void main(String[] args) {
        try {
            // 原始数据
            String data = "Hello, world!";
            // 公钥字符串（Base64编码）
            String publicKeyString = "MFwwDQYJKoZIhvcNAQEBBQADSwAwSAJBALloSaH+P1Z1Q1A/qs3gejbddklEiROWf2EadwZ68GBgzHk491icoP5x24SBOweiYA+xSqNxxFxSKuWpMu922hMCAwEAAQ==";

            // 将公钥字符串转换为公钥对象
            byte[] publicKeyBytes = Base64.getDecoder().decode(publicKeyString);
            PublicKey publicKey = KeyFactory.getInstance("RSA").generatePublic(new X509EncodedKeySpec(publicKeyBytes));

            // 创建RSA密码器
            Cipher cipher = Cipher.getInstance("RSA");
            // 使用公钥进行加密
            cipher.init(Cipher.ENCRYPT_MODE, publicKey);
            byte[] encryptedData = cipher.doFinal(data.getBytes("UTF-8"));

            // 输出加密后的数据（Base64编码）
            String encryptedDataString = Base64.getEncoder().encodeToString(encryptedData);
            System.out.println("加密后的数据：" + encryptedDataString);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

import javax.crypto.Cipher;
import java.security.KeyFactory;
import java.security.PrivateKey;
import java.security.spec.PKCS8EncodedKeySpec;

public class RSADecryptor {
    public static void main(String[] args) {
        try {
            // 加密后的数据（Base64编码）
            String encryptedDataString = "3TiTv+AE9FF8NMMFYqx8y/Qz+uzFP/JEcsKGMJP+10r7SmNSDRsjMdK5Mbcz8zvrTaWCrIP4wmUgJhD7ZNoSmQ==";
            // 私钥字符串（Base64编码）
            String privateKeyString = "MIIBOAIBAAJALloSaH+P1Z1Q1A/qs3gejbddklEiROWf2EadwZ68GBgzHk491icoP5x24SBOweiYA+xSqNxxFxSKuWpMu922hMCAwEAAQJAB+hKDm+GF1z5soiqn8DBw7SHf/XRGlxpViWOGTm+LJ6NOkOFH0RRg/cdqq9umemQvR+E6YUcM/NzqxIqJFQyQIhAO2dNYXRKeHNmKXa5vYqWYJIJtyKXXDhLvCRukRz4WFAiEAz2jl8eXSaevi8YMnxRwYnH/OgnesWr0AFr0QemF5sECIBzvqdPKUQzzw3CHjgcTJtX9p9q/MVN4upqvtbJ2WxsNAiAYET666mlWgGIca1ePAbtoB10vhWzDY5YxQ/eTkDssCQIgNoDd1BtSVbWDEUSN/9fCP6UekytJfGFeUZerYB0UlL0=";
            
            // 将私钥字符串转换为私钥对象
            byte[] privateKeyBytes = Base64.getDecoder().decode(privateKeyString);
            PrivateKey privateKey = KeyFactory.getInstance("RSA").generatePrivate(new PKCS8EncodedKeySpec(privateKeyBytes));

            // 创建RSA密码器
            Cipher cipher = Cipher.getInstance("RSA");
            // 使用私钥进行解密
            cipher.init(Cipher.DECRYPT_MODE, privateKey);
            byte[] decryptedData = cipher.doFinal(Base64.getDecoder().decode(encryptedDataString));

            // 输出解密后的数据
            String decryptedDataString = new String(decryptedData, "UTF-8");
            System.out.println("解密后的数据：" + decryptedDataString);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}