md5 加密

1.对网络传输请求参数加密 下载操作文件名加密

+ (NSString *)md5:(NSString *)input

{

    const char *cStr = [input UTF8String];

    unsigned char digest[CC_MD5_DIGEST_LENGTH];

    CC_MD5(cStr, (int32_t)strlen(cStr), digest);

    

    NSMutableString *output = [NSMutableString stringWithCapacity:CC_MD5_DIGEST_LENGTH * 2];

    

    for(int i = 0; i < CC_MD5_DIGEST_LENGTH; i++)

        [output appendFormat:@"%02x", digest[i]];

    

    return output;

    

}