加密篇之二－非对称加密算法RSA

最新推荐文章于 2023-11-13 17:05:05 发布

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最新推荐文章于 2023-11-13 17:05:05 发布

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文章标签：加密 java RSA

本文链接：https://blog.youkuaiyun.com/xuan_xiaofeng/article/details/48441067

非对称加密算法RSA提供了一种更安全的消息传输方式，通过公钥和私钥的配合使用，确保即使一方密钥被泄露，消息内容仍无法被解密。然而，RSA算法的加解密过程相对较慢。

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非对称加密算法相对对称加密算法而言更加安全。消息传输的两端，协调产生一对秘钥（公钥和私钥），公钥加密私钥解密，反之。就算秘钥中的一只被破解，也不能解析出消息的内容。但是非对称加密算法加解密花费时间长，速度慢。

RSA

// 1.生成密钥

KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA");
keyPairGenerator.initialize(512);
KeyPair keyPair =keyPairGenerator.generateKeyPair();

// 2.公钥，私钥

RSAPublicKey rsaPublicKey = (RSAPublicKey) keyPair.getPublic();
RSAPrivateKey rsaPrivateKey = (RSAPrivateKey) keyPair.getPrivate();
System.out.println("Public Key:" + Base64.encodeBase64String(rsaPublicKey.getEncoded()));
System.out.println("Private Key:" + Base64.encodeBase64String(rsaPrivateKey.getEncoded()));
PKCS8EncodedKeySpec pkcs8EncodedKeySpec = new PKCS8EncodedKeySpec(rsaPrivateKey.getEncoded());
KeyFactory keyFactory = KeyFactory.getInstance("RSA");
PrivateKey privateKey = keyFactory.generatePrivate(pkcs8EncodedKeySpec);
Cipher cipher = Cipher.getInstance("RSA");
cipher.init(Cipher.ENCRYPT_MODE,privateKey);
byte[]result =cipher.doFinal(src.getBytes());
System.out.println("私钥加密、公钥解密 ---- 加密:" + Base64.encodeBase64String(result));

// 3.私钥加密、公钥解密 ---- 解密

X509EncodedKeySpec x509EncodedKeySpec = new X509EncodedKeySpec(rsaPublicKey.getEncoded());
keyFactory = KeyFactory.getInstance("RSA");
PublicKey publicKey = keyFactory.generatePublic(x509EncodedKeySpec);
cipher = Cipher.getInstance("RSA");
cipher.init(Cipher.DECRYPT_MODE,publicKey);
result =cipher.doFinal(result);
System.out.println("私钥加密、公钥解密 ---- 解密:" +new String(result));

// 4.公钥加密、私钥解密 ---- 加密

X509EncodedKeySpec x509EncodedKeySpec2 = new X509EncodedKeySpec(rsaPublicKey.getEncoded());
KeyFactory keyFactory2 = KeyFactory.getInstance("RSA");
PublicKey publicKey2 = keyFactory2.generatePublic(x509EncodedKeySpec2);
Cipher cipher2 = Cipher.getInstance("RSA");
cipher2.init(Cipher.ENCRYPT_MODE,publicKey2);
byte[]result2 =cipher2.doFinal(src.getBytes());
System.out.println("公钥加密、私钥解密 ---- 加密:" + Base64.encodeBase64String(result2));

// 5.私钥解密、公钥加密 ---- 解密

PKCS8EncodedKeySpec pkcs8EncodedKeySpec5 = new PKCS8EncodedKeySpec(rsaPrivateKey.getEncoded());
KeyFactory keyFactory5 = KeyFactory.getInstance("RSA");
PrivateKey privateKey5 = keyFactory5.generatePrivate(pkcs8EncodedKeySpec5);
Cipher cipher5 = Cipher.getInstance("RSA");
cipher5.init(Cipher.DECRYPT_MODE,privateKey5);
byte[]result5 =cipher5.doFinal(result2);
System.out.println("公钥加密、私钥解密 ---- 解密:" +new String(result5));