RSA公私钥加密工具类

import org.apache.commons.codec.binary.Base64;
import javax.crypto.Cipher;
import java.nio.charset.StandardCharsets;
import java.security.*;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;

public class RSAEncryptUtil {


    /**
     * 公钥加密
     *
     * @param content   内容
     * @param publicKey 公钥
     * @return 加密后的密文
     * @throws Exception 异常信息
     */
    public static String encrypt(String content, String publicKey) throws Exception {
        //base64编码的公钥
        byte[] decoded = Base64.decodeBase64(publicKey);
        RSAPublicKey pubKey = (RSAPublicKey) KeyFactory.getInstance("RSA").generatePublic(new X509EncodedKeySpec(decoded));
        //RSA加密
        Cipher cipher = Cipher.getInstance("RSA");
        cipher.init(Cipher.ENCRYPT_MODE, pubKey);
        return Base64.encodeBase64String(cipher.doFinal(content.getBytes(StandardCharsets.UTF_8)));
    }

    /**
     * 私钥解密
     *
     * @param content    内容
     * @param privateKey 私钥
     * @return 解密后的字符串
     * @throws Exception 异常
     */
    public static String decrypt(String content, String privateKey) throws Exception {
        byte[] inputByte = Base64.decodeBase64(content.getBytes(StandardCharsets.UTF_8));
        byte[] decoded = Base64.decodeBase64(privateKey);
        RSAPrivateKey priKey = (RSAPrivateKey) KeyFactory.getInstance("RSA").generatePrivate(new PKCS8EncodedKeySpec(decoded));
        //RSA解密
        Cipher cipher = Cipher.getInstance("RSA");
        cipher.init(Cipher.DECRYPT_MODE, priKey);
        return new String(cipher.doFinal(inputByte));
    }

    /**
     * 随机生成密钥对
     */
    public static KeyPair genKeyPair() throws Exception {
        // KeyPairGenerator类用于生成公钥和私钥对，基于RSA算法生成对象
        KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance("RSA");
        keyPairGen.initialize(512, new SecureRandom());
        return keyPairGen.generateKeyPair();
    }

    public static void main(String[] args) throws Exception {

        KeyPair keyPair = genKeyPair();
        RSAPrivateKey privateKeyRSA = (RSAPrivateKey) keyPair.getPrivate();   // 得到私钥
        RSAPublicKey publicKeyRSA = (RSAPublicKey) keyPair.getPublic();  // 得到公钥
        String publicKey = new String(Base64.encodeBase64(publicKeyRSA.getEncoded()));
        // 得到私钥字符串
        String privateKey = new String(Base64.encodeBase64((privateKeyRSA.getEncoded())));

        String encrypt = encrypt("ldskjfsdlkjllkjlkj", publicKey);
        System.out.println("加密密文：" + encrypt);

        String decrypt = decrypt(encrypt, privateKey);
        System.out.println("解密密文：" + decrypt);

    }


}