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+{{{
+#!htmlcomment
+
+This page is maintained automatically by a script.  Don't modify this page by hand,
+your changes will just be overwritten the next time the script runs.  Talk to your
+Friendly Neighborhood Repository Maintainer if you need to change something here.
+
+}}}
+
+{{{
+#!html
+<h1>Cryptech tamper detection</h1>
+
+<p>This is software for the Atmel AVR ATtiny828 MCU on the Cryptech alpha
+board, rev02, implementing tamper detection and master key erasure.</p>
+
+<h2>Overview</h2>
+
+<pre><code>   *************
+   * P A N I C *
+   *   button  *
+   *************
+    /
+   /
+  /
+AVR ---- SPI mux ---- FPGA
+            |          |
+            |         ARM
+           MKM
+
+AVR -- Atmel MCU
+FPGA -- FPGA
+MKM -- Master Key Memory, 23K640 SRAM
+SPI mux -- 2 x MC74AC244DW
+ARM -- ARM CPU
+</code></pre>
+
+<p>The MKM holds the master key for the device.</p>
+
+<p>The AVR, MKM and the mux are all battery powered.</p>
+
+<p>The AVR and the FPGA are both sharing access to the MKM through the
+mux, with the AVR connected to the pins used for deciding who's in
+control of the memory. If the AVR doesn't actively grab control of the
+MKM, the FPGA is in control.</p>
+
+<p>When the panic button is pressed, the AVR takes control over the MKM
+and writes zeros to it as quickly as possible. In idle mode, i.e. when
+the panic button is not pressed, the AVR tries to consume as little
+power as possible.</p>
+
+<h2>Building the software</h2>
+
+<p>To build a .hex file suitible for uploading to a board with a
+ATTiny828, a C compiler for AVR is needed, as wells a objcopy. On a
+Debian system, the following command can be used for installing both:</p>
+
+<pre><code>apt-get install gcc-avr binutils-avr avr-libc
+</code></pre>
+
+<p>To build tamper.hex, type 'make' in this directory.</p>
+
+<p>To upload a .hex file to a board, the program avrdude can be used. On
+a Debian system, the following command can be used for installing
+avrdude:</p>
+
+<pre><code>apt-get install avrdude
+</code></pre>
+
+<p>If configuration for ATtiny828 is missing, the file attiny828.conf in
+this directory could be appended to avrdude.conf:</p>
+
+<pre><code>cat attiny828.conf &gt;&gt; /etc/avrdude.conf
+</code></pre>
+
+<p>Often, a piece of hardware called "SPI programmer" is needed in order
+to upload the .hex file to the target system. The one I've been using
+has "sparkfun.com" printed on it. This small board has a mini-USB port
+to connect to a host system and a header with SPI pins to connect to a
+board with an AVR on it.</p>
+
+<p>To upload a .hex file to a board, use the upload.sh shell script in
+this directory with the name of the file as the only argument:</p>
+
+<pre><code>./upload.sh tamper.hex
+</code></pre>
+
+<p>Depending on permissions on your host system you might want to run the
+upload script as root.</p>
+}}}
+
+[[RepositoryIndex(format=table,glob=user/ln5/tamper)]]
+
+|| Clone `https://git.cryptech.is/user/ln5/tamper.git` ||