java中加密演算法AES和RSA

首頁>技術>pandastar2020-12-24 21:45

java中加密演算法AES和RSA

一、簡介

對於機密資訊，我們需要加密，這裡介紹加密演算法在java中的使用。

二、知識點

目前常用的加密演算法有對稱加密演算法與非對稱加密演算法。

2.1 對稱加密演算法

在對稱加密中，加密方與解密方都共用同一個金鑰，也就是加密與解密的金鑰是一樣的。特點：

通常它的演算法公開，加解密速度快。現在常用的AES演算法，即advanced encrytion standard，

金鑰長度，目前可用的是128位。

加密的原文長度不限。

2.2 非對稱加密

非對稱加密，又稱公開金鑰加密，它有兩個金鑰，公鑰（public key）和私鑰（private key），它們是不同的。公鑰與私鑰是配對使用的，使用公鑰加密時，只有對應的私鑰才能解開；用私鑰加密時，只有對應的公鑰才能解開。特點：

通常是接收方先生成一對金鑰，即公鑰和私鑰，然後公鑰公開，傳送方用公開的公鑰加密，密方傳給接收方，然後接收方用私鑰解密。

非對稱加密沒有對稱加密速度快，常用的是RSA演算法。

RSA通常加密原文較小的串，串越大，keyGen.initialize(n)的n值就相應增大，加密解密速度越慢；

三、例項

3.1 新增base64的maven依賴

<groupId>commons-codec</groupId>

<artifactId>commons-codec</artifactId>

</dependency>

3.2 對稱加密AES程式碼例項

public class AESMain {

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

String source = "study hard and make progress everyday";

System.out.println("message source : "+source);

/********** 金鑰生成方式一：自動生成金鑰 **************/

String keyStr = genKeyAES(); //生成金鑰串

System.out.println("AES keyStr : "+keyStr);

SecretKey key = loadKeyAES(keyStr); //根據金鑰串獲取金鑰

// /********** 金鑰生成方式二：指定種子(或者可以說是密碼)生成金鑰 ***********/

// String password = "123456";

// SecretKey key = genRawKeyAES(password); //根據password獲取金鑰

// String keyStr = Base64.encodeBase64String(key.getEncoded()); //生成金鑰串

// System.out.println("AES keyStr : "+keyStr);

String encryptStr = encryptAES(source,key); //AES加密

System.out.println("AES encrypt result : " + encryptStr);

String deencryptStr = deencryptAES(encryptStr,key); //AES解密

System.out.println("AES deencrypt result : " +deencryptStr);

}

//生成金鑰串

static String genKeyAES() throws Exception {

KeyGenerator keyGen = KeyGenerator.getInstance("AES");

keyGen.init(128);

SecretKey key = keyGen.generateKey();

String keyStr = Base64.encodeBase64String(key.getEncoded());

return keyStr;

}

//根據password生成金鑰串

static String genKeyAES(String password) throws Exception {

SecretKey key = genRawKeyAES(password);

String keyStr = Base64.encodeBase64String(key.getEncoded());

return keyStr;

}

//根據password生成原始金鑰串

static SecretKey genRawKeyAES(String password) throws Exception {

KeyGenerator keyGen = KeyGenerator.getInstance("AES");

keyGen.init(128,new SecureRandom(password.getBytes("utf8")));

SecretKey key = keyGen.generateKey();

return key;

}

//根據金鑰串獲取金鑰

static SecretKey loadKeyAES(String keyStr) throws Exception {

SecretKey key = new SecretKeySpec(Base64.decodeBase64(keyStr), "AES");

return key;

}

//AES加密

static String encryptAES(String source, SecretKey key) throws Exception {

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

cipher.init(Cipher.ENCRYPT_MODE, key);

byte[] result = cipher.doFinal(source.getBytes("utf8"));

return Base64.encodeBase64String(result);

}

//AES解密

static String deencryptAES(String source, SecretKey key) throws Exception {

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

cipher.init(Cipher.DECRYPT_MODE, key);

byte[] resultByte = cipher.doFinal(Base64.decodeBase64(source));

String result = new String(resultByte,"utf-8");

return result;

}

執行結果：

message source : study hard and make progress everyday

AES keyStr : evD5UdP8LK8UrfrmxGQheA==

AES encrypt result : 1z8zSWmRRFPNb6qoURgFp1c778SzaDqbErrVroDthM5eBXrQTFevAzYmRStK7EPZ

AES deencrypt result : study hard and make progress everyday

3.3 非對稱加密演算法RSA程式碼例項

public class RSAMain {

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

String source = "study hard and make progress everyday";

System.out.println("message source : "+source);

KeyPair keyPair = getKeyPair(); //生成金鑰對

String pubKeyStr = getPubKey(keyPair); //獲取公鑰串

System.out.println("pubKeyStr : "+pubKeyStr);

String priKeyStr = getPriKey(keyPair); //獲取私鑰串

System.out.println("priKeyStr : "+priKeyStr);

PublicKey pubKey = loadPubKey(pubKeyStr);//載入公鑰

PrivateKey priKey = loadPriKey(priKeyStr);//載入私鑰

/**************** 公鑰加密私鑰解密********************/

System.out.println("\n/**************** 公鑰加密私鑰解密********************/");

String encryptStr = pubEncrypt(source,pubKey); //RSA加密

System.out.println("RSA pubKey encrypt result : " + encryptStr);

String decryptStr = priDecrypt(encryptStr,priKey); //RSA解密

System.out.println("RSA priKey decryptStr result : " +decryptStr);

/**************** 私鑰加密公鑰解密********************/

System.out.println("\n/**************** 私鑰加密公鑰解密********************/");

encryptStr = priEncrypt(source,priKey); //RSA加密

System.out.println("RSA priKey encrypt result : " + encryptStr);

decryptStr = pubDecrypt(encryptStr,pubKey); //RSA解密

System.out.println("RSA pubKey decryptStr result : " +decryptStr);

}

//生成金鑰對

static KeyPair getKeyPair() throws Exception {

KeyPairGenerator keyGen = KeyPairGenerator.getInstance("RSA");

keyGen.initialize(512); //可以理解為：加密後的密文長度，實際原文要小些越大加密解密越慢

KeyPair keyPair = keyGen.generateKeyPair();

return keyPair;

}

//獲取公鑰Base64字串

static String getPubKey(KeyPair keyPair){

PublicKey key = keyPair.getPublic();

return Base64.encodeBase64String(key.getEncoded());

}

//獲取私鑰Base64字串

static String getPriKey(KeyPair keyPair){

PrivateKey key = keyPair.getPrivate();

return Base64.encodeBase64String(key.getEncoded());

}

//根據公鑰串獲取公鑰

static PublicKey loadPubKey(String keyStr) throws Exception {

X509EncodedKeySpec keySpec = new X509EncodedKeySpec(Base64.decodeBase64(keyStr));

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

PublicKey key = keyFactory.generatePublic(keySpec);

return key;

}

//根據私鑰串獲取私鑰

static PrivateKey loadPriKey(String keyStr) throws Exception {

PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(Base64.decodeBase64(keyStr));

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

PrivateKey key = keyFactory.generatePrivate(keySpec);

return key;

}

/**************** 公鑰加密私鑰解密********************/

//使用公鑰加密

static String pubEncrypt(String source,PublicKey key) throws Exception {

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

cipher.init(Cipher.ENCRYPT_MODE,key);

return Base64.encodeBase64String(cipher.doFinal(source.getBytes("utf8")));

}

//使用私鑰解密

static String priDecrypt(String source,PrivateKey key) throws Exception {

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

cipher.init(Cipher.DECRYPT_MODE,key);

return new String(cipher.doFinal(Base64.decodeBase64(source)),"utf8");

}

/**************** 私鑰加密公鑰解密********************/

//使用私鑰加密

static String priEncrypt(String source,PrivateKey key) throws Exception {

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

cipher.init(Cipher.ENCRYPT_MODE,key);

return Base64.encodeBase64String(cipher.doFinal(source.getBytes("utf8")));

}

//使用公鑰解密

static String pubDecrypt(String source,PublicKey key) throws Exception {

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

cipher.init(Cipher.DECRYPT_MODE,key);

return new String(cipher.doFinal(Base64.decodeBase64(source)),"utf8");

}

執行結果：

message source : study hard and make progress everyday

pubKeyStr : M2wwDQYJKoZIhvcNAQEBBQADSwAwSAJBAItWYa39aUhRTIXEIBCSfSCp9CvXj/k9STtMv7y5OVD9ILArIf8ZwU+qepahkO40EUJ37IBS3ciiTw7CcS7U7UsCAwEAAQ==

priKeyStr : M2IBUwIBADANBgkqhkiG9w0BAQEFAASCAT0wggE5AgEAAkEAi1Zhrf1pSFFMhcQgEJJ9IKn0K9eP+T1JO0y/vLk5UP0gsCsh/xnBT6p6lqGQ7jQRQnfsgFLdyKJPDsJxLtTtSwIDAQABAkBeSJNMIl9tWeXH1hBEZntY8OeSCwkXA8tb3vEXCNap37p06hj5d2gqaK/ZkgBqVfY6keCcRqbkOROyxdfCQTjBAiEA49WvON+HhlApKXHhHglz9bmpu+LLp6NGDicTLszfGLECIQCckAMKaWcn8u1V+svGbIBHxiKI+QUBXbbo6sUZt/UkuwIgEDpcLLTfNlXnWKhf3H/X3pzG1jclQl+C0ec+morFKUECIE5CMjLnIvg2FuqOdYOWwrydzq93Akh/hqmAiMtlR7V3AiBVblFmuDimgKb8OWg+2BaWTuKZA/BG9Z8nsT2tqaNuSA==

/**************** 公鑰加密私鑰解密********************/

RSA pubKey encrypt result : do1DUKBnm9J49+IhFDqPEI53tGX69kPfPbqYsPPEabm9NYTvNiEEUzjT5w1j1yQtxlz7T2n6QyHKHv0BjZOoqg==

RSA priKey decryptStr result : study hard and make progress everyday

/**************** 私鑰加密公鑰解密********************/

RSA priKey encrypt result : S6bEfnsciTRNmdqe3mh9LBUsyYS5Qff6nj2xRxaiyhi2/Frw17snIZfB0rOTSnu7JjamjLZozaJ/WlwdEFcloA==

RSA pubKey decryptStr result : study hard and make progress everyday

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java中加密演算法AES和RSA

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