java RSA 加解密

import java.security.Key;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.PrivateKey;
import java.security.PublicKey;
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 sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;
 
 
public class RSAHelper {
 
      /**
       * 得到公钥
       * @param key 密钥字符串（经过base64编码）
       * @throws Exception
       */
      public static PublicKey getPublicKey(String key) throws Exception {
            byte[] keyBytes;
            keyBytes = (new BASE64Decoder()).decodeBuffer(key);
 
            X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);
            KeyFactory keyFactory = KeyFactory.getInstance("RSA");
            PublicKey publicKey = keyFactory.generatePublic(keySpec);
            return publicKey;
      }
      /**
       * 得到私钥
       * @param key 密钥字符串（经过base64编码）
       * @throws Exception
       */
      public static PrivateKey getPrivateKey(String key) throws Exception {
            byte[] keyBytes;
            keyBytes = (new BASE64Decoder()).decodeBuffer(key);
 
            PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(keyBytes);
            KeyFactory keyFactory = KeyFactory.getInstance("RSA");
            PrivateKey privateKey = keyFactory.generatePrivate(keySpec);
            return privateKey;
      }
 
      /**
       * 得到密钥字符串（经过base64编码）
       * @return
       */
      public static String getKeyString(Key key) throws Exception {
            byte[] keyBytes = key.getEncoded();
            String s = (new BASE64Encoder()).encode(keyBytes);
            return s;
      }
 
 
      public static void main(String[] args) throws Exception {
 
            KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance("RSA");
            //密钥位数
            keyPairGen.initialize(1024);
            //密钥对
            KeyPair keyPair = keyPairGen.generateKeyPair();
 
            // 公钥
            PublicKey publicKey = (RSAPublicKey) keyPair.getPublic();
 
            // 私钥
            PrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();
 
            String publicKeyString = getKeyString(publicKey);
            System.out.println("public:\n" + publicKeyString);
 
            String privateKeyString = getKeyString(privateKey);
            System.out.println("private:\n" + privateKeyString);
 
            //加解密类
            Cipher cipher = Cipher.getInstance("RSA");//Cipher.getInstance("RSA/ECB/PKCS1Padding");
 
            //明文
            byte[] plainText = "我们都很好！邮件：@sina.com".getBytes();
 
            //加密
            cipher.init(Cipher.ENCRYPT_MODE, publicKey);
        byte[] enBytes = cipher.doFinal(plainText);
 
//通过密钥字符串得到密钥
            publicKey = getPublicKey(publicKeyString);
            privateKey = getPrivateKey(privateKeyString);
 
            //解密
            cipher.init(Cipher.DECRYPT_MODE, privateKey);
            byte[]deBytes = cipher.doFinal(enBytes);
 
            publicKeyString = getKeyString(publicKey);
            System.out.println("public:\n" +publicKeyString);
 
            privateKeyString = getKeyString(privateKey);
            System.out.println("private:\n" + privateKeyString);
 
            String s = new String(deBytes);
            System.out.println(s);
 
 
      }
 
}

 

通过modulus \public exponent \private exponent生成 RSA Key

import java.math.BigInteger;

import java.security.KeyFactory;

import java.security.PrivateKey;

import java.security.PublicKey;

import java.security.spec.RSAPrivateKeySpec;

import java.security.spec.RSAPublicKeySpec;

 

import javax.crypto.Cipher;

 

public class RsaKey {

 

      public PublicKey getPublicKey(String modulus,String publicExponent) throws Exception {

            BigInteger m = new BigInteger(modulus);

            BigInteger e = new BigInteger(publicExponent);

            RSAPublicKeySpec keySpec = new RSAPublicKeySpec(m,e);

            KeyFactory keyFactory = KeyFactory.getInstance("RSA");

            PublicKey publicKey = keyFactory.generatePublic(keySpec);

            return publicKey;

      }

 

      public PrivateKey getPrivateKey(String modulus,String privateExponent) throws Exception {

            BigInteger m = new BigInteger(modulus);

            BigInteger e = new BigInteger(privateExponent);

            RSAPrivateKeySpec keySpec = new RSAPrivateKeySpec(m,e);

            KeyFactory keyFactory = KeyFactory.getInstance("RSA");

            PrivateKey privateKey = keyFactory.generatePrivate(keySpec);

            return privateKey;

      }

 

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

            String modulus = "10103166745709600780215616551837697832816413714471062522342538060943596036859967333870827790358555455232243383580565187280643159050869924436081447583051139";

            String publicExponent = "65537";

            String privateExponet = "367979294475011322800474185715497882523349856362702385535371444397399388741997039894583483410120364529325888461124714276674612930833020362278754665756193";

 

            RsaKey key = new RsaKey();

            PublicKey publicKey = key.getPublicKey(modulus, publicExponent);

            PrivateKey privateKey = key.getPrivateKey(modulus, privateExponet);

 

 

            //加解密类

            Cipher cipher = Cipher.getInstance("RSA");

 

            //明文

            byte[] plainText = "我们都很好！邮件：@sina.com".getBytes();

 

            //加密

            cipher.init(Cipher.ENCRYPT_MODE, publicKey);

        byte[] enBytes = cipher.doFinal(plainText);

 

 

        cipher.init(Cipher.DECRYPT_MODE, privateKey);

            byte[]deBytes = cipher.doFinal(enBytes);

 

            String s = new String(deBytes);

            System.out.println(s);

 

      }

}