objective-c实现authCode 解决php与ios通信加密的问题

最近项目中要加密与服务器的通讯内容,主要是为了防止恶意的抓包利用,本来这样的加密直接在网上就可以找到的,但是无奈关于OC的几乎都来自同一个模版,加密出来的字符窜无法被PHP后端解析,并且也没有有效时间的参数,所以只能对照PHP的加密代码写一个OC版的,其中PHP的很多方法,在OC当中远远没有一句话那么简单(::>_<::>

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#import #define STRING_SPLICE(a,b)     ([NSString stringWithFormat:@"%@%@",(NSString *)(a),(NSString *)(b)])//字符串拼接

+ (NSString *)md5:(NSString *)str {    const char *cStr = [str UTF8String];    unsigned char result[16];    CC_MD5(cStr, strlen(cStr), result); // This is the md5 call        return [NSString stringWithFormat:            @"%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x",            result[0], result[1], result[2], result[3],            result[4], result[5], result[6], result[7],            result[8], result[9], result[10], result[11],            result[12], result[13], result[14], result[15]            ];}

// param: 要加密的字符串// operation: 传入@"ENCODE" 为加密,解密没有写,所以只要不传"DECODE"就OK了// expiry: 有效时间,单位是秒,默认时0,就是没有时效,如果设置后超出有效时间,将无法被解密+ (NSString *)encryption:(NSString *)param operation:(NSString *)operation expiry:(int)expiry{    NSString *key = @"1992326qa";   // 加密的密钥    NSString *DECODE = @"DECODE";    param = [param stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];    operation = operation ? operation : DECODE;    expiry = expiry ? expiry : 0;    int keyLength = 4;    key = [self md5:key];    NSString *keya = [self md5:[key substringToIndex:16]];    NSString *keyb = [self md5:[key substringFromIndex:16]];    NSString *time = [self microtime];    NSString *keyc = keyLength ? ([operation isEqualToString:DECODE] ? [param substringToIndex:keyLength] : [[self md5:time] substringFromIndex:[self md5:time].length - keyLength]) : @"";    NSString *cryptkey = STRING_SPLICE(keya, [self md5:STRING_SPLICE(keya, keyc)]);    keyLength = cryptkey.length;    param = [NSString stringWithFormat:@"%@%@%@",([NSString stringWithFormat:@"%010d",expiry ? expiry + (int)[[NSDate dateWithTimeIntervalSinceNow:0] timeIntervalSince1970] : expiry]),[[self md5: STRING_SPLICE(param,keyb)] substringToIndex:16],param];    int paramLength = param.length;    NSString *result = @"";    NSMutableArray *box = [NSMutableArray arrayWithCapacity:UnicodeCount];    for (int i = 0; i    
+ (NSString *)microtime // 计算时间串{    NSDate *currentDate = [NSDate dateWithTimeIntervalSinceNow:0];    NSTimeInterval interval = [currentDate timeIntervalSince1970];    NSString *intervalStr = [NSString stringWithFormat:@"%f00",interval];    NSString *pre = [intervalStr substringWithRange:NSMakeRange(intervalStr.length - 8, 8)];    NSString *suf = [intervalStr substringToIndex:intervalStr.length - 9];    NSString *result = [NSString stringWithFormat:@"0.%@ %@",pre,suf];    return result;}
   
+ (int)ord:(NSString *)str index:(int)index  // 获取字符串某一位的ASCII码{    int asciiCode = [str characterAtIndex:index];    return asciiCode;}
   
+ (const char)chr:(int)asciiCode  // 通过ASCII码获取字符{    return [[NSString stringWithFormat:@"%C",(unichar)asciiCode] characterAtIndex:0];}
   
+ (NSString *)strChr:(int)asciiCode // 通过ASCII码获取字符串{    NSString *data = [NSString stringWithFormat:@"%C",(unichar)asciiCode]; //A    return data;}
   
+ (NSString *)base64:(NSString *)str // base64编码{    NSString *base64EncodedString = [[str dataUsingEncoding:NSUTF8StringEncoding] base64EncodedStringWithOptions:0];    return base64EncodedString;}
   
注意:
   

• 只有加密算法(因为我不需要解密)
• 如果需要加密汉字,加密过程中,会出现空格字符,而后端会解析失败,所以在后台解析iOS端时,要将加密串中的空格替换为+号,才能保证每次解析成功

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问题:

• 因为加密过程中需要转换ASCII码,但是Mac和Window的ASCII码在127位以后就不一样了,所以我们只能利用前127位ASCII码

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我也是先留着,搞不好什么时候又用到了~