3DES加密—java/OC

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


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：

Java代码


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：

Java代码


//

// 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

Java代码


//

// 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;

}

@end

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。

原文：http://www.iteye.com/topic/1127949