March 2017
Intermediate to advanced
262 pages
5h 26m
Chinese
Content preview from 物联网设备安全
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电子撬锁
——
滥用门锁危害物理安全
｜
45
2.1.2
磁条
我们生活中经常遇到磁条卡，从信用卡、公共交通卡到酒店房卡，我们依赖磁条卡获取
服务和进入特定场所。图
2-2
展示了一张典型的带有磁性条带（即磁条）的信用卡的背面。
标签
①
指磁性条，
②
是签名条，
③
表示卡的安全码（
CSC
）。下文中讨论的酒店房卡，
通常只有背面的磁条与正面的酒店标志。
图 2-2：带磁条的卡片
通常，磁条包含
3
个存储不同数据块的独立磁道。磁道
1
和
2
一般用于金融行业的
ATM
、借记卡和信用卡，并没有限定哪个机构使用特定的磁道。
Onity
门锁使用磁道
3
，
它包含以下数据序列：
16
位识别码
一个识别码包含了卡能开的房门和卡的复制版本信息。为酒店员工创建主卡时，通
过存储的一个值代表酒店员工的身份而不是门的标识。当客人入住酒店时，为指定
房间的门制作的第一张卡的复制标识位设置为
0
，接下来的复制卡标识位依次加
1
，
以便识别。
8
位标志字节
用一个字节设置各种其他选项的值。
16
位过期日期
客人办理入住手续时，设置门卡的有效时长。
24
位未知位
设置为全
0
。
24
位钥匙编码
该值被写入单个门锁。这时，门锁中配置一个提前量。例如，一把门锁的钥匙编码
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I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.