RSAUtil

package com.example.demo.rsa1;

import java.io.IOException;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;

import javax.crypto.Cipher;

import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;

public class RSAUtil {
    //生成祕鑰對
    public static KeyPair getKeyPair() throws Exception {
        KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA");
        keyPairGenerator.initialize(3072);
        KeyPair keyPair = keyPairGenerator.generateKeyPair();
        return keyPair;
    }

    //獲取公鑰(Base64編碼)
    public static String getPublicKey(KeyPair keyPair){
        PublicKey publicKey = keyPair.getPublic();
        byte[] bytes = publicKey.getEncoded();
        return byte2Base64(bytes);
    }

    //獲取私鑰(Bas