用RSA加密实现Web登录密码加密传输
通常我们做一个Web应用程序的时候都需要登录，登录就要输入用户名和登录密码，并且，用户名和登录密码都是明文传输的，这样就有可能在中途被别人拦截，尤其是在网吧等场合。
所以，我打算自己实现一个密码加密传输方法。
这里使用了RSA非对称加密算法，对称加密也许大家都已经很熟悉，也就是加密和解密用的都是同样的密钥，没有密钥，就无法解密，这是对称加密。而非对称加密算法中，加密所用的密钥和解密所用的密钥是不相同的：你使用我的公钥加密，我使用我的私钥来解密；如果你不使用我的公钥加密，那我无法解密；如果我没有私钥，我也没法解密。
我设计的这个登录密码加密传输方法的原理图如下：
代码
package com.blog.server.util;import org.apache.tomcat.util.codec.binary.Base64;
import org.apache.tomcat.util.http.fileupload.IOUtils;import javax.crypto.Cipher;
import java.io.ByteArrayOutputStream;
import java.security.*;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.HashMap;
import java.util.Map;/*** Created by cuiran on 19/1/9.*/
public class RSAUtils {public static final String CHARSET = "UTF-8";public static final String RSA_ALGORITHM = "RSA";public static Map<String, String> createKeys(){//为RSA算法创建一个KeyPairGenerator对象KeyPairGenerator kpg;try{kpg = KeyPairGenerator.getInstance(RSA_ALGORITHM);}catch(NoSuchAlgorithmException e){throw new IllegalArgumentException("No such algorithm-->[" + RSA_ALGORITHM + "]");}int keySize = 1024;//初始化KeyPairGenerator对象,密钥长度kpg.initialize(keySize);//生成密匙对KeyPair keyPair = kpg.generateKeyPair();//得到公钥Key publicKey = keyPair.getPublic();String publicKeyStr = Base64.encodeBase64URLSafeString(publicKey.getEncoded());//得到私钥Key privateKey = keyPair.getPrivate();String privateKeyStr = Base64.encodeBase64URLSafeString(privateKey.getEncoded());Map<String, String> keyPairMap = new HashMap<String, String>();keyPairMap.put("publicKey", publicKeyStr);keyPairMap.put("privateKey", privateKeyStr);return keyPairMap;}/*** 得到公钥* @param publicKey 密钥字符串（经过base64编码）* @throws Exception*/public static RSAPublicKey getPublicKey(String publicKey) throws NoSuchAlgorithmException, InvalidKeySpecException {//通过X509编码的Key指令获得公钥对象KeyFactory keyFactory = KeyFactory.getInstance(RSA_ALGORITHM);X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(Base64.decodeBase64(publicKey));RSAPublicKey key = (RSAPublicKey) keyFactory.generatePublic(x509KeySpec);return key;}/*** 得到私钥* @param privateKey 密钥字符串（经过base64编码）* @throws Exception*/public static RSAPrivateKey getPrivateKey(String privateKey) throws NoSuchAlgorithmException, InvalidKeySpecException {//通过PKCS#8编码的Key指令获得私钥对象KeyFactory keyFactory = KeyFactory.getInstance(RSA_ALGORITHM);PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(Base64.decodeBase64(privateKey));RSAPrivateKey key = (RSAPrivateKey) keyFactory.generatePrivate(pkcs8KeySpec);return key;}/*** 公钥加密* @param data* @param publicKey* @return*/public static String publicEncrypt(String data, RSAPublicKey publicKey){try{Cipher cipher = Cipher.getInstance(RSA_ALGORITHM);cipher.init(Cipher.ENCRYPT_MODE, publicKey);return Base64.encodeBase64URLSafeString(rsaSplitCodec(cipher, Cipher.ENCRYPT_MODE, data.getBytes(CHARSET), publicKey.getModulus().bitLength()));}catch(Exception e){throw new RuntimeException("加密字符串[" + data + "]时遇到异常", e);}}/*** 私钥解密* @param data* @param privateKey* @return*/public static String privateDecrypt(String data, RSAPrivateKey privateKey){try{Cipher cipher = Cipher.getInstance(RSA_ALGORITHM);cipher.init(Cipher.DECRYPT_MODE, privateKey);return new String(rsaSplitCodec(cipher, Cipher.DECRYPT_MODE, Base64.decodeBase64(data), privateKey.getModulus().bitLength()), CHARSET);}catch(Exception e){throw new RuntimeException("解密字符串[" + data + "]时遇到异常", e);}}/*** 私钥加密* @param data* @param privateKey* @return*/public static String privateEncrypt(String data, RSAPrivateKey privateKey){try{Cipher cipher = Cipher.getInstance(RSA_ALGORITHM);cipher.init(Cipher.ENCRYPT_MODE, privateKey);return Base64.encodeBase64URLSafeString(rsaSplitCodec(cipher, Cipher.ENCRYPT_MODE, data.getBytes(CHARSET), privateKey.getModulus().bitLength()));}catch(Exception e){throw new RuntimeException("加密字符串[" + data + "]时遇到异常", e);}}/*** 公钥解密* @param data* @param publicKey* @return*/public static String publicDecrypt(String data, RSAPublicKey publicKey){try{Cipher cipher = Cipher.getInstance(RSA_ALGORITHM);cipher.init(Cipher.DECRYPT_MODE, publicKey);return new String(rsaSplitCodec(cipher, Cipher.DECRYPT_MODE, Base64.decodeBase64(data), publicKey.getModulus().bitLength()), CHARSET);}catch(Exception e){throw new RuntimeException("解密字符串[" + data + "]时遇到异常", e);}}private static byte[] rsaSplitCodec(Cipher cipher, int opmode, byte[] datas, int keySize){int maxBlock = 0;if(opmode == Cipher.DECRYPT_MODE){maxBlock = keySize / 8;}else{maxBlock = keySize / 8 - 11;}ByteArrayOutputStreamout = new ByteArrayOutputStream();int offSet = 0;byte[] buff;int i = 0;try{while(datas.length > offSet){if(datas.length-offSet > maxBlock){buff = cipher.doFinal(datas, offSet, maxBlock);}else{buff = cipher.doFinal(datas, offSet, datas.length-offSet);}out.write(buff, 0, buff.length);i++;offSet = i * maxBlock;}}catch(Exception e){throw new RuntimeException("加解密阀值为["+maxBlock+"]的数据时发生异常", e);}byte[] resultDatas = out.toByteArray();IOUtils.closeQuietly(out);return resultDatas;}public static void main (String[] args) throws Exception {Map<String, String> keyMap = RSAUtils.createKeys();String publicKey = keyMap.get("publicKey");String privateKey = keyMap.get("privateKey");System.out.println("公钥: \n\r" + publicKey);System.out.println("私钥： \n\r" + privateKey);System.out.println("公钥加密——私钥解密");String str = "code_cayden";System.out.println("\r明文：\r\n" + str);System.out.println("\r明文大小：\r\n" + str.getBytes().length);System.out.println("加密用的公钥：\r\n"+ RSAUtils.getPublicKey(publicKey));System.out.println("解密用的私钥：\r\n"+ RSAUtils.getPrivateKey(privateKey));String encodedData = RSAUtils.publicEncrypt(str, RSAUtils.getPublicKey(publicKey));System.out.println("密文：\r\n" + encodedData);String decodedData = RSAUtils.privateDecrypt(encodedData, RSAUtils.getPrivateKey(privateKey));System.out.println("解密后文字: \r\n" + decodedData);}}本文来自互联网用户投稿，文章观点仅代表作者本人，不代表本站立场，不承担相关法律责任。如若转载，请注明出处。 如若内容造成侵权/违法违规/事实不符，请点击【内容举报】进行投诉反馈！