iOS DES ECB模式对称加密解密

浏览数：28 / 时间：2015年06月11日

最近忙于android和iOS的项目，写完了android的DES 的ECB模式加密解密（相关连接：http://blog.csdn.net/vipa1888/article/details/8086037），又回到了Ios上面，因为本人也是最近今年开始研究ios的，所以Ios上面好多东西都不懂，进过了半年的研究，终于吧ios的DES 的ECB模式对称加密解密搞定了，本人遇到的问题很严重的问题，网上写的好多16进制数转化位字节都有问题的，经过本人研究发现他们有一个地方写错了，导致解密后的NSString 位null，我的代码已经修复了这个问题，下面贴出源代码供大家参考：

首先贴出加密类的头文件：

//
//  DesUtil.h
//  Author:spring sky
//  QQ:840950105
//  Email:[email protected]
//

#import <Foundation/Foundation.h>

@interface DesUtil : NSObject
/**
 DES加密
 */
+(NSString *) encryptUseDES:(NSString *)plainText key:(NSString *)key;

/**
 DES解密
 */
+(NSString *) decryptUseDES:(NSString *)plainText key:(NSString *)key;



@end

加密类的实现类：

//
//  DesUtil.m
//  Author:spring sky
//  QQ:840950105
//  Email:[email protected]
//

#import "DesUtil.h"
#import <CommonCrypto/CommonCryptor.h>
#import "ConverUtil.h"
@implementation DesUtil


static Byte iv[] = {1,2,3,4,5,6,7,8};
/*
 DES加密
 */
+(NSString *) encryptUseDES:(NSString *)clearText key:(NSString *)key
{
    NSString *ciphertext = nil;
    NSData *textData = [clearText dataUsingEncoding:NSUTF8StringEncoding];
    NSUInteger dataLength = [clearText length];
    unsigned char buffer[1024];
    memset(buffer, 0, sizeof(char));
    size_t numBytesEncrypted = 0;
    
    
    CCCryptorStatus cryptStatus = CCCrypt(kCCEncrypt, kCCAlgorithmDES,
                                          kCCOptionECBMode,
                                          [key UTF8String], kCCKeySizeDES,
                                          iv,
                                          [textData bytes]    , dataLength,
                                          buffer, 1024,
                                          &numBytesEncrypted);
    if (cryptStatus == kCCSuccess) {
        NSLog(@"DES加密成功");
        NSData *data = [NSData dataWithBytes:buffer length:(NSUInteger)numBytesEncrypted];
        Byte* bb = (Byte*)[data bytes];
        ciphertext = [ConverUtil parseByteArray2HexString:bb];
    }else{
        NSLog(@"DES加密失败");
    }
    return ciphertext;
}

/**
 DES解密
 */
+(NSString *) decryptUseDES:(NSString *)plainText key:(NSString *)key
{
    NSString *cleartext = nil;
    NSData *textData = [ConverUtil parseHexToByteArray:plainText];
    NSUInteger dataLength = [textData length];
    unsigned char buffer[1024];
    memset(buffer, 0, sizeof(char));
    size_t numBytesEncrypted = 0;
    
    
    CCCryptorStatus cryptStatus = CCCrypt(kCCDecrypt, kCCAlgorithmDES,
                                          kCCOptionECBMode,
                                          [key UTF8String], kCCKeySizeDES,
                                          iv,
                                          [textData bytes]    , dataLength,
                                          buffer, 1024,
                                          &numBytesEncrypted);
    if (cryptStatus == kCCSuccess) {
        NSLog(@"DES解密成功");

        NSData *data = [NSData dataWithBytes:buffer length:(NSUInteger)numBytesEncrypted];
        cleartext = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
    }else{
        NSLog(@"DES解密失败");
    }
    return cleartext;
}



@end

下面是转码类，主要是16进制和字节的转化

头文件：

//
//  ConverUtil.h
//  Author:spring sky
//  QQ:840950105
//  Email:[email protected]
//

#import <Foundation/Foundation.h>

@interface ConverUtil : NSObject

/**
 64编码
 */
+(NSString *)base64Encoding:(NSData*) text;

/**
 字节转化为16进制数
 */
+(NSString *) parseByte2HexString:(Byte *) bytes;

/**
 字节数组转化16进制数
 */
+(NSString *) parseByteArray2HexString:(Byte[]) bytes;

/*
 将16进制数据转化成NSData 数组
 */
+(NSData*) parseHexToByteArray:(NSString*) hexString;

@end

实现类：

//
//  ConverUtil.m
//  Author:spring sky
//  QQ:840950105
//  Email:[email protected]
//

#import "ConverUtil.h"

@implementation ConverUtil
static const char encodingTable[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

/**
 64编码
 */
+(NSString *)base64Encoding:(NSData*) text
{
    if (text.length == 0)
        return @"";
    
    char *characters = malloc(text.length*3/2);
    
    if (characters == NULL)
        return @"";
    
    int end = text.length - 3;
    int index = 0;
    int charCount = 0;
    int n = 0;
    
    while (index <= end) {
        int d = (((int)(((char *)[text bytes])[index]) & 0x0ff) << 16)
        | (((int)(((char *)[text bytes])[index + 1]) & 0x0ff) << 8)
        | ((int)(((char *)[text bytes])[index + 2]) & 0x0ff);
        
        characters[charCount++] = encodingTable[(d >> 18) & 63];
        characters[charCount++] = encodingTable[(d >> 12) & 63];
        characters[charCount++] = encodingTable[(d >> 6) & 63];
        characters[charCount++] = encodingTable[d & 63];
        
        index += 3;
        
        if(n++ >= 14)
        {
            n = 0;
            characters[charCount++] = ‘ ‘;
        }
    }
    
    if(index == text.length - 2)
    {
        int d = (((int)(((char *)[text bytes])[index]) & 0x0ff) << 16)
        | (((int)(((char *)[text bytes])[index + 1]) & 255) << 8);
        characters[charCount++] = encodingTable[(d >> 18) & 63];
        characters[charCount++] = encodingTable[(d >> 12) & 63];
        characters[charCount++] = encodingTable[(d >> 6) & 63];
        characters[charCount++] = ‘=‘;
    }
    else if(index == text.length - 1)
    {
        int d = ((int)(((char *)[text bytes])[index]) & 0x0ff) << 16;
        characters[charCount++] = encodingTable[(d >> 18) & 63];
        characters[charCount++] = encodingTable[(d >> 12) & 63];
        characters[charCount++] = ‘=‘;
        characters[charCount++] = ‘=‘;
    }
    NSString * rtnStr = [[NSString alloc] initWithBytesNoCopy:characters length:charCount encoding:NSUTF8StringEncoding freeWhenDone:YES];
    return rtnStr;
}

/**
 字节转化为16进制数
 */
+(NSString *) parseByte2HexString:(Byte *) bytes
{
    NSMutableString *hexStr = [[NSMutableString alloc]init];
    int i = 0;
    if(bytes)
    {
        while (bytes[i] != ‘\0‘)
        {
            NSString *hexByte = [NSString stringWithFormat:@"%x",bytes[i] & 0xff];///16进制数
            if([hexByte length]==1)
                [hexStr appendFormat:@"0%@", hexByte];
            else
                [hexStr appendFormat:@"%@", hexByte];
            
            i++;
        }
    }
    NSLog(@"bytes 的16进制数为:%@",hexStr);
    return hexStr;
}


/**
 字节数组转化16进制数
 */
+(NSString *) parseByteArray2HexString:(Byte[]) bytes
{
    NSMutableString *hexStr = [[NSMutableString alloc]init];
    int i = 0;
    if(bytes)
    {
        while (bytes[i] != ‘\0‘)
        {
            NSString *hexByte = [NSString stringWithFormat:@"%x",bytes[i] & 0xff];///16进制数
            if([hexByte length]==1)
                [hexStr appendFormat:@"0%@", hexByte];
            else
                [hexStr appendFormat:@"%@", hexByte];
            
            i++;
        }
    }
    NSLog(@"bytes 的16进制数为:%@",hexStr);
    return [hexStr uppercaseString];
}

/*
 将16进制数据转化成NSData 数组
 */
+(NSData*) parseHexToByteArray:(NSString*) hexString
{
    int j=0;
    Byte bytes[hexString.length]; 
    for(int i=0;i<[hexString length];i++)
    {
        int int_ch;  /// 两位16进制数转化后的10进制数
        unichar hex_char1 = [hexString characterAtIndex:i]; ////两位16进制数中的第一位(高位*16)
        int int_ch1;
        if(hex_char1 >= ‘0‘ && hex_char1 <=‘9‘)
            int_ch1 = (hex_char1-48)*16;   //// 0 的Ascll - 48
        else if(hex_char1 >= ‘A‘ && hex_char1 <=‘F‘)
            int_ch1 = (hex_char1-55)*16; //// A 的Ascll - 65
        else
            int_ch1 = (hex_char1-87)*16; //// a 的Ascll - 97
        i++;
        unichar hex_char2 = [hexString characterAtIndex:i]; ///两位16进制数中的第二位(低位)
        int int_ch2;
        if(hex_char2 >= ‘0‘ && hex_char2 <=‘9‘)
            int_ch2 = (hex_char2-48); //// 0 的Ascll - 48
        else if(hex_char2 >= ‘A‘ && hex_char1 <=‘F‘)
            int_ch2 = hex_char2-55; //// A 的Ascll - 65
        else
            int_ch2 = hex_char2-87; //// a 的Ascll - 97
        
        int_ch = int_ch1+int_ch2;
        bytes[j] = int_ch;  ///将转化后的数放入Byte数组里
        j++;
    }

    NSData *newData = [[NSData alloc] initWithBytes:bytes length:hexString.length/2];
    NSLog(@"newData=%@",newData);
    return newData;
}

@end