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。
package org.liuyq.des3;import java.security.Key;import javax.crypto.Cipher;import javax.crypto.SecretKeyFactory;import javax.crypto.spec.DESedeKeySpec;import javax.crypto.spec.IvParameterSpec;/** * 3DES加密工具类 */public class Des3 { // 密钥 private final static String secretKey = "liuyunqiang@lx100$#365#$"; // 向量 private final static String iv = "01234567"; // 加解密统一使用的编码方式 private final static String encoding = "utf-8"; /** * 3DES加密 * * @param plainText 普通文本 * @return * @throws Exception */ public static String encode(String plainText) throws Exception { Key deskey = null; DESedeKeySpec spec = new DESedeKeySpec(secretKey.getBytes()); SecretKeyFactory keyfactory = SecretKeyFactory.getInstance("desede"); deskey = keyfactory.generateSecret(spec); Cipher cipher = Cipher.getInstance("desede/CBC/PKCS5Padding"); IvParameterSpec ips = new IvParameterSpec(iv.getBytes()); cipher.init(Cipher.ENCRYPT_MODE, deskey, ips); byte[] encryptData = cipher.doFinal(plainText.getBytes(encoding)); return Base64.encode(encryptData); } /** * 3DES解密 * * @param encryptText 加密文本 * @return * @throws Exception */ public static String decode(String encryptText) throws Exception { Key deskey = null; DESedeKeySpec spec = new DESedeKeySpec(secretKey.getBytes()); SecretKeyFactory keyfactory = SecretKeyFactory.getInstance("desede"); deskey = keyfactory.generateSecret(spec); Cipher cipher = Cipher.getInstance("desede/CBC/PKCS5Padding"); IvParameterSpec ips = new IvParameterSpec(iv.getBytes()); cipher.init(Cipher.DECRYPT_MODE, deskey, ips); byte[] decryptData = cipher.doFinal(Base64.decode(encryptText)); return new String(decryptData, encoding); }}上面的加密工具类会使用到Base64这个类，该类的源代码如下：
import java.io.ByteArrayOutputStream;import java.io.IOException;import java.io.OutputStream;/** * Base64编码工具类 */public class Base64 { private static final char[] legalChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/".toCharArray(); public static String encode(byte[] data) { int start = 0; int len = data.length; StringBuffer buf = new StringBuffer(data.length * 3 / 2); int end = len - 3; int i = start; int n = 0; while (i <= end) { int d = ((((int) data[i]) & 0x0ff) << 16) | ((((int) data[i + 1]) & 0x0ff) << 8) | (((int) data[i + 2]) & 0x0ff); buf.append(legalChars[(d >> 18) & 63]); buf.append(legalChars[(d >> 12) & 63]); buf.append(legalChars[(d >> 6) & 63]); buf.append(legalChars[d & 63]); i += 3; if (n++ >= 14) { n = 0; buf.append(" "); } } if (i == start + len - 2) { int d = ((((int) data[i]) & 0x0ff) << 16) | ((((int) data[i + 1]) & 255) << 8); buf.append(legalChars[(d >> 18) & 63]); buf.append(legalChars[(d >> 12) & 63]); buf.append(legalChars[(d >> 6) & 63]); buf.append("="); } else if (i == start + len - 1) { int d = (((int) data[i]) & 0x0ff) << 16; buf.append(legalChars[(d >> 18) & 63]); buf.append(legalChars[(d >> 12) & 63]); buf.append("=="); } return buf.toString(); } private static int decode(char c) { if (c >= 'A' && c <= 'Z') return ((int) c) - 65; else if (c >= 'a' && c <= 'z') return ((int) c) - 97 + 26; else if (c >= '0' && c <= '9') return ((int) c) - 48 + 26 + 26; else switch (c) { case '+': return 62; case '/': return 63; case '=': return 0; default: throw new RuntimeException("unexpected code: " + c); } } /** * Decodes the given Base64 encoded String to a new byte array. The byte array holding the decoded data is returned. */ public static byte[] decode(String s) { ByteArrayOutputStream bos = new ByteArrayOutputStream(); try { decode(s, bos); } catch (IOException e) { throw new RuntimeException(); } byte[] decodedBytes = bos.toByteArray(); try { bos.close(); bos = null; } catch (IOException ex) { System.err.println("Error while decoding BASE64: " + ex.toString()); } return decodedBytes; } private static void decode(String s, OutputStream os) throws IOException { int i = 0; int len = s.length(); while (true) { while (i < len && s.charAt(i) <= ' ') i++; if (i == len) break; int tri = (decode(s.charAt(i)) << 18) + (decode(s.charAt(i + 1)) << 12) + (decode(s.charAt(i + 2)) << 6) + (decode(s.charAt(i + 3))); os.write((tri >> 16) & 255); if (s.charAt(i + 2) == '=') break; os.write((tri >> 8) & 255); if (s.charAt(i + 3) == '=') break; os.write(tri & 255); i += 4; } }}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：
//// DES3Util.h//#import <Foundation/Foundation.h>@interface DES3Util : NSObject {}// 加密方法+ (NSString*)encrypt:(NSString*)plainText;// 解密方法+ (NSString*)decrypt:(NSString*)encryptText;@end//// DES3Util.m//#import "DES3Util.h"#import <CommonCrypto/CommonCryptor.h>#import "GTMBase64.h"#define gkey @"liuyunqiang@lx100$#365#$"#define gIv @"01234567"@implementation DES3Util// 加密方法+ (NSString*)encrypt:(NSString*)plainText { NSData* data = [plainText dataUsingEncoding:NSUTF8StringEncoding]; size_t plainTextBufferSize = [data length]; const void *vplainText = (const void *)[data bytes]; CCCryptorStatus ccStatus; uint8_t *bufferPtr = NULL; size_t bufferPtrSize = 0; size_t movedBytes = 0; bufferPtrSize = (plainTextBufferSize + kCCBlockSize3DES) & ~(kCCBlockSize3DES - 1); bufferPtr = malloc( bufferPtrSize * sizeof(uint8_t)); memset((void *)bufferPtr, 0x0, bufferPtrSize); const void *vkey = (const void *) [gkey UTF8String]; const void *vinitVec = (const void *) [gIv UTF8String]; ccStatus = CCCrypt(kCCEncrypt, kCCAlgorithm3DES, kCCOptionPKCS7Padding, vkey, kCCKeySize3DES, vinitVec, vplainText, plainTextBufferSize, (void *)bufferPtr, bufferPtrSize, &movedBytes); NSData *myData = [NSData dataWithBytes:(const void *)bufferPtr length:(NSUInteger)movedBytes]; NSString *result = [GTMBase64 stringByEncodingData:myData]; return result;}// 解密方法+ (NSString*)decrypt:(NSString*)encryptText { NSData *encryptData = [GTMBase64 decodeData:[encryptText dataUsingEncoding:NSUTF8StringEncoding]]; size_t plainTextBufferSize = [encryptData length]; const void *vplainText = [encryptData bytes]; CCCryptorStatus ccStatus; uint8_t *bufferPtr = NULL; size_t bufferPtrSize = 0; size_t movedBytes = 0; bufferPtrSize = (plainTextBufferSize + kCCBlockSize3DES) & ~(kCCBlockSize3DES - 1); bufferPtr = malloc( bufferPtrSize * sizeof(uint8_t)); memset((void *)bufferPtr, 0x0, bufferPtrSize); const void *vkey = (const void *) [gkey UTF8String]; const void *vinitVec = (const void *) [gIv UTF8String]; ccStatus = CCCrypt(kCCDecrypt, kCCAlgorithm3DES, kCCOptionPKCS7Padding, vkey, kCCKeySize3DES, vinitVec, vplainText, plainTextBufferSize, (void *)bufferPtr, bufferPtrSize, &movedBytes); NSString *result = [[[NSString alloc] initWithData:[NSData dataWithBytes:(const void *)bufferPtr length:(NSUInteger)movedBytes] encoding:NSUTF8StringEncoding] autorelease]; return result;}@endiPhone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。
借鉴地址：http://blog.csdn.net/lyq8479/article/details/8062867