[[!meta title="ChaosKey"]]
# ChaosKey
This is a hardware True Random Number Generator that attaches via USB.
The Linux Kernel, starting with version 4.1, includes source for this
driver. It should be built by default in your distribution. If your
using Linux + KVM to host other Linux instances, read the
[VirtualMachine](VirtualMachine.html) page to see how you can configure the guests to share
the host entropy source.
## Version 1.0 ##
ChaosKey is now out of production. They work great, but it took several years
to sell our first production run, and shipping them from the US to other
countries one at a time ended up dominating the net cost to most users. We might
make more some day, but no promises!
### Reflashing Firmware ###
To reflash the system firmware on ChaosKey, you first need to get the
device into 'bootloader mode'. To do this, you must power-up ChaosKey
with a jumper between GND and the Boot Loader Select pin.
Open up ChaosKey by prying the case apart. There's no glue or screws,
so a thin tool or fingernail should suffice to split the case into two
pieces. Once you've opened it up, you'll find the inside that looks
much like this:
Connect a wire between the two red holes in the debug connector and
then plug it in to your computer. It will appear as a USB modem device
called AltosFlash with USB ID fffe:000a.
Use the 'ao-usbload' program, which is part of the
[AltOS repository](https://altusmetrum.org/AltOS/)
and is packaged for Debian in the 'altos' package:
$ ao-usbload chaoskey-v1.0-*.elf
### Version 1.0 Hardware ###
* [STM32F042](http://www.st.com/web/catalog/mmc/FM141/SC1169/SS1574/LN1823?icmp=stm32f0x2-line_pron_pr_jan2014&sc=stm32f0x2-pr) System-on-Chip
* ARM Cortex-M0 MCU
* 32k Flash
* 6k RAM
* USB 2.0 Full Speed
* Crystal-less operation
* 20V noise source
* AP3015A boost regulator
* back-to-back 3904 transistor noise
* [OPA356](http://www.ti.com/product/opa356) op amp
* 200MHz GBP
Here's a circuit diagram of the noise source:
### Version 1.0 Bits ###
Source code for the firmware, flash loader and a utility to pull raw
bits from the noise source are available here:
[AltOS Git Repository](http://git.gag.com/?p=fw/altos;a=summary)
[ChaosKey Firmware version 1.6.7](v1.0/chaoskey-v1.0-1.6.7.elf)
[ChaosKey Boot Loader version 1.6.7](v1.0/chaoskey-v1.0-altos-flash-1.6.7.elf)
Hardware designs using [gEDA](http://www.geda-project.org/) are
available here:
[ChaosKey Hardware Design Files](http://git.gag.com/?p=hw/chaoskey;a=summary)
## Version 0.3 ##
This one uses the better noise source coupled with an op amp that
provides 2MHz of bandwidth at a gain of 100, offering linear frequency
response at a million samples per second.
A photo of prototype version 0.3:
Here's a circuit diagram of the noise source:
Version 0.3 uses the same hardware design as version 1.0, except that
it uses a QFP package version of the processor instead of the QFN used
in 1.0, and hence needs a larger circuit board.
## Version 0.2 ##
This version uses a better noise source, but the single transistor amp
designed to get from the 20mV noise source to a digital value doesn't
provide enough bandwidth, so the resulting signal seen by the CPU has
poor frequency response.
Here's a photo of prototype version 0.2:
### Version 0.2 Hardware ###
* [STM32F042](http://www.st.com/web/catalog/mmc/FM141/SC1169/SS1574/LN1823?icmp=stm32f0x2-line_pron_pr_jan2014&sc=stm32f0x2-pr) System-on-Chip
* ARM Cortex-M0 MCU
* 32k Flash
* 6k RAM
* USB 2.0
* Crystal-less operation
* 20V noise source
* AP3015A boost regulator
* back-to-back 3904 transistor noise
## Version 0.1 ##
These are photos of prototype version 0.1:
### Version 0.1 Hardware ###
* [NXP LPC11U14](http://www.nxp.com/products/microcontrollers/cortex_m0_m0/LPC11U14FHI33.html) System-on-Chip
* ARM Cortex-M0 MCU
* 32k Flash
* 6k RAM
* USB 2.0
* 8 12-bit analog inputs
* I2C, SPI, async serial
* digital I/O
* ZXRE1004 zener diode noise source
* MCP6L92 dual op-amp
## Software ##
* Firmware Features
* [AltOS](../AltOS/) is written mostly in C with some ARM assembler
* Tools Used
* [gEDA](http://www.gpleda.org/) for schematic capture and PCB layout
* [GCC](http://gcc.gnu.org/) compiler and source debugger
* Licenses
* The hardware is licensed under the [TAPR](http://www.tapr.org) [Open Hardware License](http://www.tapr.org/ohl.html)
* The software is licensed [GPL version 2](http://www.gnu.org/licenses/old-licenses/gpl-2.0.html)
### Reflashing Firmware ###
To reflash the system firmware on ChaosKey, you first need to get the
device into 'bootloader mode'. To do this, you must power-up ChaosKey
with a jumper between GND and the Boot Loader Select pin.
Open up ChaosKey by prying the case apart. There's no glue or screws,
so a thin tool or fingernail should suffice to split the case into two
pieces. Once you've opened it up, you'll find the inside that looks
much like this:
Here's a circuit diagram of the noise source:
### Version 0.2 Hardware ###
* [STM32F042](http://www.st.com/web/catalog/mmc/FM141/SC1169/SS1574/LN1823?icmp=stm32f0x2-line_pron_pr_jan2014&sc=stm32f0x2-pr) System-on-Chip
* ARM Cortex-M0 MCU
* 32k Flash
* 6k RAM
* USB 2.0
* Crystal-less operation
* 20V noise source
* AP3015A boost regulator
* back-to-back 3904 transistor noise
## Version 0.1 ##
These are photos of prototype version 0.1:
### Version 0.1 Hardware ###
* [NXP LPC11U14](http://www.nxp.com/products/microcontrollers/cortex_m0_m0/LPC11U14FHI33.html) System-on-Chip
* ARM Cortex-M0 MCU
* 32k Flash
* 6k RAM
* USB 2.0
* 8 12-bit analog inputs
* I2C, SPI, async serial
* digital I/O
* ZXRE1004 zener diode noise source
* MCP6L92 dual op-amp
## Software ##
* Firmware Features
* [AltOS](../AltOS/) is written mostly in C with some ARM assembler
* Tools Used
* [gEDA](http://www.gpleda.org/) for schematic capture and PCB layout
* [GCC](http://gcc.gnu.org/) compiler and source debugger
* Licenses
* The hardware is licensed under the [TAPR](http://www.tapr.org) [Open Hardware License](http://www.tapr.org/ohl.html)
* The software is licensed [GPL version 2](http://www.gnu.org/licenses/old-licenses/gpl-2.0.html)