RSA加解密-Java

import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import javax.crypto.Cipher;
import org.apache.commons.codec.binary.Base64;

/**
 * @Author: kylin
 * @Date: 2019/3/27 下午3:25
 */
public class RSAUtil {

  /**
   * 随机生成密钥对
   */
  public static void genKeyPair() throws NoSuchAlgorithmException {
    // 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(1024, new SecureRandom());
    KeyPair keyPair = keyPairGen.generateKeyPair();
    RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();
    RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();
    String publicKeyString = new String(Base64.encodeBase64(publicKey.getEncoded()));
    String privateKeyString = new String(Base64.encodeBase64((privateKey.getEncoded())));
  }

  /**
   * 公钥加密
   */
  public static String encrypt(String str, 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);
    String outStr = Base64.encodeBase64String(cipher.doFinal(str.getBytes("UTF-8")));
    return outStr;
  }

  /**
   * 私钥解密
   */
  public static String decrypt(String str, String privateKey) throws Exception {
    //64位解码加密后的字符串
    byte[] inputByte = Base64.decodeBase64(str.getBytes("UTF-8"));
    //base64编码的私钥
    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);
    String outStr = new String(cipher.doFinal(inputByte));
    return outStr;
  }

}

分别是生成密钥对、加密以及解密