iOS开发 OC与java相对应的3DES加解密

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;

} @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。