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Java書寫的RAS加密解密

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 { 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; } 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; } 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"); //金鑰位數 keyPairGen.initialize(1024); //金鑰對 KeyPair keyPair = keyPairGen.generateKeyPair(); // 公鑰 PublicKey publicKey = (RSAPublicKey) keyPair.getPublic(); // 私鑰 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); //加解密類 Cipher cipher = Cipher.getInstance("RSA");//Cipher.getInstance("RSA/ECB/PKCS1Padding"); //明文 byte[] plainText = "我們都很好!郵件:@sina.com".getBytes(); //加密 cipher.init(Cipher.ENCRYPT_MODE, publicKey); byte[] enBytes = cipher.doFinal(plainText); //通過金鑰字串得到金鑰 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); } }