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java 非對(duì)稱加密算法RSA實(shí)現(xiàn)詳解

更新時(shí)間：2019年07月27日 16:13:03 作者：小破孩123

這篇文章主要介紹了java 非對(duì)稱加密算法RSA實(shí)現(xiàn)詳解,文中通過示例代碼介紹的非常詳細(xì)，對(duì)大家的學(xué)習(xí)或者工作具有一定的參考學(xué)習(xí)價(jià)值,需要的朋友可以參考下

現(xiàn)在就為大家介紹一種基于因子分解的RSA算法，這種加密算法有兩種實(shí)現(xiàn)形式：1、公鑰加密，私鑰解密；2、私鑰加密，公鑰解密。下面就為大家分析一下實(shí)現(xiàn)代碼，相對(duì)于DH算法，RSA顯得有些簡(jiǎn)單。
初始化密鑰：

KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA");
      keyPairGenerator.initialize(512);
      KeyPair keyPair = keyPairGenerator.generateKeyPair();
      RSAPrivateKey rsaprivateKey = (RSAPrivateKey)keyPair.getPrivate();//私有密鑰
      RSAPublicKey rsapublicKey = (RSAPublicKey)keyPair.getPublic();//公有密鑰
      System.out.println("privateKey : "+Base64.encodeBase64String(rsaprivateKey.getEncoded()));
      System.out.println("publicKey : "+Base64.encodeBase64String(rsapublicKey.getEncoded()));

1、私鑰加密，公鑰解密：

//私鑰加密，公鑰解密--加密
      PKCS8EncodedKeySpec pkcs8EncodedKeySpec = new PKCS8EncodedKeySpec(rsaprivateKey.getEncoded());
      KeyFactory privateKeyFactory = KeyFactory.getInstance("RSA");
      PrivateKey privateKey = privateKeyFactory.generatePrivate(pkcs8EncodedKeySpec);
      Cipher privateCipher = Cipher.getInstance("RSA");
      privateCipher.init(Cipher.ENCRYPT_MODE, privateKey);
      byte[] result = privateCipher.doFinal(src.getBytes());
      System.out.println("私鑰加密，公鑰解密--加密:"+Base64.encodeBase64String(result));
      
      //私鑰加密，公鑰解密--解密
      X509EncodedKeySpec x509EncodedKeySpec = new X509EncodedKeySpec(rsapublicKey.getEncoded());
      KeyFactory publicKeyFactory = KeyFactory.getInstance("RSA");
      PublicKey publicKey = publicKeyFactory.generatePublic(x509EncodedKeySpec);
      Cipher publicCipher = Cipher.getInstance("RSA");
      publicCipher.init(Cipher.DECRYPT_MODE, publicKey);
      result = publicCipher.doFinal(result);
      System.out.println("私鑰加密，公鑰解密--解密:"+new String(result));

2、公鑰加密，私鑰解密：

//公鑰加密，私鑰解密---加密
      x509EncodedKeySpec = new X509EncodedKeySpec(rsapublicKey.getEncoded());
      publicKeyFactory = KeyFactory.getInstance("RSA");
      publicKey = publicKeyFactory.generatePublic(x509EncodedKeySpec);
      publicCipher = Cipher.getInstance("RSA");
      publicCipher.init(Cipher.ENCRYPT_MODE, publicKey);
      result = publicCipher.doFinal(src.getBytes());
      System.out.println("公鑰加密，私鑰解密---加密:"+Base64.encodeBase64String(result));
      
      //公鑰加密，私鑰解密---解密
      pkcs8EncodedKeySpec = new PKCS8EncodedKeySpec(rsaprivateKey.getEncoded());
      privateKeyFactory = KeyFactory.getInstance("RSA");
      privateKey = privateKeyFactory.generatePrivate(pkcs8EncodedKeySpec);
      privateCipher = Cipher.getInstance("RSA");
      privateCipher.init(Cipher.DECRYPT_MODE, privateKey);
      result = privateCipher.doFinal(result);
      System.out.println("公鑰加密，私鑰解密---解密:"+new String(result));

根據(jù)輸出的結(jié)果不難發(fā)現(xiàn)，公鑰和私鑰并不一致，私鑰的長(zhǎng)度要大于公鑰。

以上就是本文的全部?jī)?nèi)容，希望對(duì)大家的學(xué)習(xí)有所幫助，也希望大家多多支持腳本之家。

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