如題，上OC代碼：

- (NSString *)lowerMD5{
    const char *cStr = [self UTF8String];
    unsigned char digest[CC_MD5_DIGEST_LENGTH];
    CC_MD5( cStr, (unsigned int)self.length, digest );
    NSMutableString *result = [NSMutableString stringWithCapacity:CC_MD5_DIGEST_LENGTH * 2];
    for(int i = 0; i < CC_MD5_DIGEST_LENGTH; i++)
        [result appendFormat:@"%02x", digest[i]];
    return result;
}

服務端采用PHP 的md5
經過http://www.cmd5.com/ 的驗證，OC的漢字加密也是對不上