现在就为大家介绍一种基于因子分解的RSA算法，这种加密算法有两种实现形式：1、公钥加密，私钥解密；2、私钥加密，公钥解密。下面就为大家分析一下实现代码，相对于DH算法，RSA显得有些简单。
初始化密钥：

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

1、私钥加密，公钥解密：

//私钥加密，公钥解密--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("私钥加密，公钥解密--加密:"+Base64.encodeBase64String(result)); //私钥加密，公钥解密--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("私钥加密，公钥解密--解密:"+new String(result));

2、公钥加密，私钥解密：

//公钥加密，私钥解密---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("公钥加密，私钥解密---加密:"+Base64.encodeBase64String(result)); //公钥加密，私钥解密---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("公钥加密，私钥解密---解密:"+new String(result));

根据输出的结果不难发现，公钥和私钥并不一致，私钥的长度要大于公钥。

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。