DES加密（支持ARC与MRC）

源文件：

YXCrypto.h 与 YXCrypto.m

////  YXCrypto.h//  用秘钥给字符串加密或者解密////  Created by YouXian on 14-11-16.//  Copyright (c) 2014年 YouXian. All rights reserved.//#import 
    
     @interface YXCrypto : NSObject/*! * 给字符串加密 */+ (NSString *)DesEncryptString:(NSString*)src WithKey:(NSString *)key;/*! * 给字符串解密 */+ (NSString *)DesDecryptString:(NSString*)src WithKey:(NSString *)key;@end
    

////  YXCrypto.m//  用秘钥给字符串加密或者解密////  Created by YouXian on 14-11-16.//  Copyright (c) 2014年 YouXian. All rights reserved.//#import "YXCrypto.h"#import 
    
     #if __has_feature(objc_arc)// ARC#define Auto_Release(obj)#define Safe_Release(obj)#else// 非ARC#define Auto_Release(obj) [obj autorelease]#define Safe_Release(obj) [obj release]; obj = nil#endifstatic YXCrypto *shareInstance = nil;@implementation YXCrypto/*! * 给字符串加密 */+ (NSString *)DesEncryptString:(NSString*)src WithKey:(NSString *)key {    NSString* strRet = @"";        if (shareInstance == nil)    {        shareInstance = [[YXCrypto alloc] init];    }        // encrypt source content    NSData* bytes = [src dataUsingEncoding:NSUTF8StringEncoding];    NSData* data = [shareInstance DesCryptWithOperation:kCCEncrypt                                                  bytes:bytes                                                    key:key];        // format bytes to visible string    char* pBuff = (char*)[data bytes];    for (int i=0; i
     
      , ?, @,        0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F,    };        // decode source content to bytes    unsigned char* bytes = (unsigned char*)malloc((src.length+1)*sizeof(unsigned char));    [[src uppercaseString] getCString:(char*)bytes maxLength:src.length+1 encoding:NSUTF8StringEncoding];    unsigned char *p1 = bytes, *p2 = bytes;    unsigned long n = src.length/2;    for (int i=0; i
     
    

此类是用类方法，使用非常便利：