移动开发中遇到的最让人纠结的要属Java、Android和iPhone三个平台加解密不一致的问题。因为手机端后台通常是用JAVA开发的Web
Service，Android和iPhone客户端调用同样的Web Service接口，为了数据安全考虑，要对数据进行加密。头疼的问题就来了，很难编写出一套加密程序，在3个平台间加解密的结果一致，总不能为Android和iPhone两个客户端各写一套Web Service接口吧？我相信还会有很多朋友为此困惑，在此分享一套3DES加密程序，能够实现Java、Android和iPhone三个平台加解密一致。
首先是JAVA端的加密工具类，它同样适用于Android端，无需任何修改，即可保证Java与Android端的加解密一致，并且中文不会乱码。
Java代码
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package org.liuyq.des3;
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import java.security.Key;
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import javax.crypto.Cipher;
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import javax.crypto.SecretKeyFactory;
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import javax.crypto.spec.DESedeKeySpec;
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import javax.crypto.spec.IvParameterSpec;
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/**
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* 3DES加密工具类
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*/
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public class Des3 {
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// 密钥
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private final static String secretKey = "liuyunqiang@lx100$#365#$";
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// 向量
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private final static String iv = "01234567";
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// 加解密统一使用的编码方式
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private final static String encoding = "utf-8";
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/**
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* 3DES加密
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*
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* @param plainText 普通文本
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* @return
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* @throws Exception
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*/
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public static String encode(String plainText) throws Exception {
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Key deskey = null;
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DESedeKeySpec spec = new DESedeKeySpec(secretKey.getBytes());
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SecretKeyFactory keyfactory = SecretKeyFactory.getInstance("desede");
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deskey = keyfactory.generateSecret(spec);
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Cipher cipher = Cipher.getInstance("desede/CBC/PKCS5Padding");
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IvParameterSpec ips = new IvParameterSpec(iv.getBytes());
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cipher.init(Cipher.ENCRYPT_MODE, deskey, ips);
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byte[] encryptData = cipher.doFinal(plainText.getBytes(encoding));
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return Base64.encode(encryptData);
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}
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/**
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* 3DES解密
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*
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* @param encryptText 加密文本
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* @return
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* @throws Exception
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*/
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public static String decode(String encryptText) throws Exception {
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Key deskey = null;
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DESedeKeySpec spec = new DESedeKeySpec(secretKey.getBytes());
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SecretKeyFactory keyfactory = SecretKeyFactory.getInstance("desede");
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deskey = keyfactory.generateSecret(spec);
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Cipher cipher = Cipher.getInstance("desede/CBC/PKCS5Padding");
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IvParameterSpec ips = new IvParameterSpec(iv.getBytes());
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cipher.init(Cipher.DECRYPT_MODE, deskey, ips);
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byte[] decryptData = cipher.doFinal(Base64.decode(encryptText));
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return new String(decryptData, encoding);
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}
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}
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复制代码
上面的加密工具类会使用到Base64这个类，该类的源代码如下： Java代码
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import java.io.ByteArrayOutputStream;
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import java.io.IOException;
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import java.io.OutputStream;
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/**
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* Base64编码工具类
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*/
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public class Base64 {
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private static final char[] legalChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/".toCharArray();
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public static String encode(byte[] data) {
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int start = 0;
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int len = data.length;
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StringBuffer buf = new StringBuffer(data.length * 3 / 2);
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int end = len - 3;
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int i = start;
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int n = 0;
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while (i <= end) {
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int d = ((((int) data[i]) & 0x0ff) << 16) | ((((int) data[i + 1]) & 0x0ff) << 8) | (((int) data[i + 2]) & 0x0ff);
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buf.append(legalChars[(d >> 18) & 63]);
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buf.append(legalChars[(d >> 12) & 63]);
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buf.append(legalChars[(d >> 6) & 63]);
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buf.append(legalChars[d & 63]);
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i += 3;
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if (n++ >= 14) {
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n = 0;
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buf.append(" ");
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}
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}
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if (i == start + len - 2) {
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int d = ((((int) data[i]) & 0x0ff) << 16) | ((((int) data[i + 1]) & 255) << 8);
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buf.append(legalChars[(d >> 18) & 63]);
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buf.append(legalChars[(d >> 12) & 63]);
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buf.append(legalChars[(d >> 6) & 63]);
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buf.append("=");
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} else if (i == start + len - 1) {
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int d = (((int) data[i]) & 0x0ff) << 16;
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buf.append(legalChars[(d >> 18) & 63]);
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buf.append(legalChars[(d >> 12) & 63]);
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buf.append("==");
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}
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return buf.toString();
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}
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private static int decode(char c) {
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if (c >= 'A' && c <= 'Z')
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return ((int) c) - 65;
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else if (c >= 'a' && c <= 'z')
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return ((int) c) - 97 + 26;
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else if (c >= '0' && c <= '9')
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return ((int) c) - 48 + 26 + 26;
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else
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switch (c) {
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case '+':
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return 62;
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case '/':
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return 63;
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case '=':
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return 0;
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default:
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throw new RuntimeException("unexpected code: " + c);
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}
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}
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/**
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* Decodes the given Base64 encoded String to a new byte array. The byte array holding the decoded data is returned.
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*/
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public static byte[] decode(String s) {
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ByteArrayOutputStream bos = new ByteArrayOutputStream();
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try {
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decode(s, bos);
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} catch (IOException e) {
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throw new RuntimeException();
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}
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byte[] decodedBytes = bos.toByteArray();
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try {
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bos.close();
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bos = null;
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} catch (IOException ex) {
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System.err.println("Error while decoding BASE64: " + ex.toString());
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}
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return decodedBytes;
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}
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private static void decode(String s, OutputStream os) throws IOException {
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int i = 0;
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int len = s.length();
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while (true) {
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while (i < len && s.charAt(i) <= ' ')
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i++;
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if (i == len)
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break;
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int tri = (decode(s.charAt(i)) << 18) + (decode(s.charAt(i + 1)) << 12) + (decode(s.charAt(i + 2)) << 6) + (decode(s.charAt(i + 3)));
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os.write((tri >> 16) & 255);
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if (s.charAt(i + 2) == '=')
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break;
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os.write((tri >> 8) & 255);
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if (s.charAt(i + 3) == '=')
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break;
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os.write(tri & 255);
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i += 4;
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}
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}
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}
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复制代码
接下来是iPhone端的加密程序，当然是用Ojbective-C写的3DES加密程序，源代码如下：
Java代码
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//
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// DES3Util.h
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//
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#import <Foundation/Foundation.h>
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@interface DES3Util : NSObject {
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}
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// 加密方法
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+ (NSString*)encrypt:(NSString*)plainText;
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// 解密方法
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+ (NSString*)decrypt:(NSString*)encryptText;
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@end
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复制代码
Java代码
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//
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// DES3Util.m
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//
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#import "DES3Util.h"
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#import <CommonCrypto/CommonCryptor.h>
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#import "GTMBase64.h"
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#define gkey @"liuyunqiang@lx100$#365#$"
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#define gIv @"01234567"
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@implementation DES3Util
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// 加密方法
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+ (NSString*)encrypt:(NSString*)plainText {
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NSData* data = [plainText dataUsingEncoding:NSUTF8StringEncoding];
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size_t plainTextBufferSize = [data length];
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const void *vplainText = (const void *)[data bytes];
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CCCryptorStatus ccStatus;
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uint8_t *bufferPtr = NULL;
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size_t bufferPtrSize = 0;
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size_t movedBytes = 0;
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bufferPtrSize = (plainTextBufferSize + kCCBlockSize3DES) & ~(kCCBlockSize3DES - 1);
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bufferPtr = malloc( bufferPtrSize * sizeof(uint8_t));
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memset((void *)bufferPtr, 0x0, bufferPtrSize);
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const void *vkey = (const void *) [gkey UTF8String];
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const void *vinitVec = (const void *) [gIv UTF8String];
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ccStatus = CCCrypt(kCCEncrypt,
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kCCAlgorithm3DES,
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kCCOptionPKCS7Padding,
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vkey,
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kCCKeySize3DES,
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vinitVec,
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vplainText,
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plainTextBufferSize,
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(void *)bufferPtr,
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bufferPtrSize,
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&movedBytes);
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NSData *myData = [NSData dataWithBytes:(const void *)bufferPtr length:(NSUInteger)movedBytes];
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NSString *result = [GTMBase64 stringByEncodingData:myData];
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return result;
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}
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// 解密方法
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+ (NSString*)decrypt:(NSString*)encryptText {
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NSData *encryptData = [GTMBase64 decodeData:[encryptText dataUsingEncoding:NSUTF8StringEncoding]];
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size_t plainTextBufferSize = [encryptData length];
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const void *vplainText = [encryptData bytes];
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CCCryptorStatus ccStatus;
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uint8_t *bufferPtr = NULL;
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size_t bufferPtrSize = 0;
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size_t movedBytes = 0;
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bufferPtrSize = (plainTextBufferSize + kCCBlockSize3DES) & ~(kCCBlockSize3DES - 1);
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bufferPtr = malloc( bufferPtrSize * sizeof(uint8_t));
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memset((void *)bufferPtr, 0x0, bufferPtrSize);
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const void *vkey = (const void *) [gkey UTF8String];
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const void *vinitVec = (const void *) [gIv UTF8String];
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ccStatus = CCCrypt(kCCDecrypt,
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kCCAlgorithm3DES,
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kCCOptionPKCS7Padding,
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vkey,
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kCCKeySize3DES,
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vinitVec,
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vplainText,
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plainTextBufferSize,
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(void *)bufferPtr,
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bufferPtrSize,
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&movedBytes);
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NSString *result = [[[NSString alloc] initWithData:[NSData dataWithBytes:(const void *)bufferPtr
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length:(NSUInteger)movedBytes] encoding:NSUTF8StringEncoding] autorelease];
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return result;
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}
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@end
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复制代码
iPhone端的加密工具类中引入了“GTMBase64.h”，这是iOS平台的Base64编码工具类，就不在这里贴出相关代码了，需要的百度一下就能找到。
这样，JAVA，Android和iPhone三个平台的加密不一致问题就可以解决了。其实，对此问题，还有一种更好的实现方式，那就是用C语言写一套加密程序，这样在iOS平台是可以直接使用C程序的，而在Java和Android端通过JNI去调用C语言编写的加密方法，这样也可以实现3个平台调用同一套加密程序。