如何取消NTAG216中的密码保护? [英] How to remove password protection in NTAG216?

问题描述

我能够找到一种使用密码保护标签的方法，问题是我不知道如何删除它.根据此数据表，如果您将AUTH0的值设置为超出其范围，密码将被禁用，我尝试这样做但没有任何反应.

I was able to find a way to protect a tag with a password, the problem is that I don't know how to remove it. According to this datasheet, if you set the value of AUTH0 outside its range, the password will be disabled, I tried doing that but nothing happened.

这是我尝试禁用密码的方式:

This is how I am trying to disable the password:

• 打开标签
• 验证标签
• 将AUTH0(第41页，第三个字节)的值设置为256(根据数据表，AUTH0的范围是0到255)
• 关闭标签

推荐答案

1. 您表示您更改了第41页的AUTH0(0x29).这是NTAG213的配置页面的位置.如果您有NTAG216，则配置页从第227页(0xE3)开始.因此，AUTH0是页面0xE3的第三个字节.

1. You indicate that you change AUTH0 on page 41 (0x29). This is the location of the configuration pages for NTAG213. If you have an NTAG216, the configuration pages start at page 227 (0xE3). Hence, AUTH0 is the third byte of page 0xE3.

为了更新AUTH0的值，配置页必须是可写的.在对标签进行身份验证时，您已经确保暂时禁用了基于密码的可逆写保护(或读+写保护).但是，也有可能通过配置锁定位(CFGLCK，页面0xE4(或NTAG213的页面0x2A)的第一个字节的第6位)对配置页进行永久性写保护.不能更改AUTH0的值.因此，应检查该值，以确保甚至可以在标签上更新AUTH0.

In order to update the value of AUTH0, the configuration pages must be writable. As you authenticate to the tag, you already make sure that the password-based reversible write protection (or read+write protection) is temporarily disabled. However, there is also the possibility that the configuration pages are permanently write-protected through the configuration lock bit (CFGLCK, 6th bit of the first byte on page 0xE4 (or page 0x2A for NTAG213). If this bit is set to 1, the value of AUTH0 cannot be changed. So you should check this value in order to be sure that updating AUTH0 is even possible on your tag.

根本无法将字节值(AUTH0)设置为0-255范围之外的任何值.字节值由8位组成，因此只能保存0到2 ⁸ -1的值.如果您使用(byte) 256之类的东西，则等同于(byte) 0.因此，您很可能将值设置为0，指示整个标签应受密码保护.实际上，您应该将AUTH0设置为最后一页地址之后的值(即，对于NTAG216至少为0xE7，对于NTAG213至少为0x2D，或者仅仅是0xFF(255)).

Setting a byte value (AUTH0) to anything outside the range 0-255 is simply not possible. A byte value consists of 8 bits and can, therefore, only hold values from 0 to 2⁸-1. If you use something like (byte) 256 then this is eqivalent to (byte) 0. Hence, you most likely set the value to 0 indicating that the whole tag should be password protected. You should actually set AUTH0 to a value past the last page address (i.e. at least 0xE7 for NTAG216, at least 0x2D for NTAG213, or simply 0xFF (255)).

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