1 [[!meta title="ChaosKey"]]
4 This is a hardware True Random Number Generator that attaches via USB.
6 The Linux Kernel, starting with version 4.1, includes source for this
7 driver. It should be built by default in your distribution. If your
8 using Linux + KVM to host other Linux instances, read the
9 [VirtualMachine](VirtualMachine.html) page to see how you can configure the guests to share
10 the host entropy source.
14 ChaosKey is now out of production, but some units may still be available through our
16 [vikings](https://store.vikings.net/chaoskey).
18 <a href="v1.0/chaoskey-bare.jpg"><img src="v1.0/chaoskey-bare-thumb.jpg"></a>
20 <a href="v1.0/chaoskey-boxed.jpg"><img src="v1.0/chaoskey-boxed-thumb.jpg"></a>
22 ### Reflashing Firmware ###
24 To reflash the system firmware on ChaosKey, you first need to get the
25 device into 'bootloader mode'. To do this, you must power-up ChaosKey
26 with a jumper between GND and the Boot Loader Select pin.
28 Open up ChaosKey by prying the case apart. There's no glue or screws,
29 so a thin tool or fingernail should suffice to split the case into two
30 pieces. Once you've opened it up, you'll find the inside that looks
33 <img src="chaoskey-connector.svg">
35 Connect a wire between the two red holes in the debug connector and
36 then plug it in to your computer. It will appear as a USB modem device
37 called AltosFlash with USB ID fffe:000a.
39 Use the 'ao-usbload' program, which is part of the
40 [AltOS repository](https://altusmetrum.org/AltOS/)
41 and is packaged for Debian in the 'altos' package:
43 $ ao-usbload chaoskey-v1.0-*.elf
45 ### Version 1.0 Hardware ###
47 * [STM32F042](http://www.st.com/web/catalog/mmc/FM141/SC1169/SS1574/LN1823?icmp=stm32f0x2-line_pron_pr_jan2014&sc=stm32f0x2-pr) System-on-Chip
52 * Crystal-less operation
54 * AP3015A boost regulator
55 * back-to-back 3904 transistor noise
56 * [OPA356](http://www.ti.com/product/opa356) op amp
59 Here's a circuit diagram of the noise source:
61 <img src="v1.0/noise-source.svg">
63 ### Version 1.0 Bits ###
65 Source code for the firmware, flash loader and a utility to pull raw
66 bits from the noise source are available here:
68 [AltOS Git Repository](http://git.gag.com/?p=fw/altos;a=summary)
70 [ChaosKey Firmware version 1.6.7](v1.0/chaoskey-v1.0-1.6.7.elf)
72 [ChaosKey Boot Loader version 1.6.7](v1.0/chaoskey-v1.0-altos-flash-1.6.7.elf)
74 Hardware designs using [gEDA](http://www.geda-project.org/) are
77 [ChaosKey Hardware Design Files](http://git.gag.com/?p=hw/chaoskey;a=summary)
82 This one uses the better noise source coupled with an op amp that
83 provides 2MHz of bandwidth at a gain of 100, offering linear frequency
84 response at a million samples per second.
86 A photo of prototype version 0.3:
88 <a href="v0.3/chaoskey-v0.3.jpg"> <img src="v0.3/chaoskey-v0.3-thumb.jpg"></a>
90 Here's a circuit diagram of the noise source:
92 <img src="v0.3/noise-source.svg">
94 Version 0.3 uses the same hardware design as version 1.0, except that
95 it uses a QFP package version of the processor instead of the QFN used
96 in 1.0, and hence needs a larger circuit board.
100 This version uses a better noise source, but the single transistor amp
101 designed to get from the 20mV noise source to a digital value doesn't
102 provide enough bandwidth, so the resulting signal seen by the CPU has
103 poor frequency response.
105 Here's a photo of prototype version 0.2:
107 <a href="v0.2/chaoskey-v0.2.jpg"> <img src="v0.2/chaoskey-v0.2-thumb.jpg"></a>
109 ### Version 0.2 Hardware ###
111 * [STM32F042](http://www.st.com/web/catalog/mmc/FM141/SC1169/SS1574/LN1823?icmp=stm32f0x2-line_pron_pr_jan2014&sc=stm32f0x2-pr) System-on-Chip
116 * Crystal-less operation
118 * AP3015A boost regulator
119 * back-to-back 3904 transistor noise
123 These are photos of prototype version 0.1:
125 <a href="v0.1/chaoskey-v0.1-top.jpg"> <img src="v0.1/chaoskey-v0.1-top-thumb.jpg"></a>
126 <a href="v0.1/chaoskey-v0.1-bottom.jpg"> <img src="v0.1/chaoskey-v0.1-bottom-thumb.jpg"></a>
128 ### Version 0.1 Hardware ###
130 * [NXP LPC11U14](http://www.nxp.com/products/microcontrollers/cortex_m0_m0/LPC11U14FHI33.html) System-on-Chip
135 * 8 12-bit analog inputs
136 * I2C, SPI, async serial
138 * ZXRE1004 zener diode noise source
139 * MCP6L92 dual op-amp
144 * [AltOS](../AltOS/) is written mostly in C with some ARM assembler
146 * [gEDA](http://www.gpleda.org/) for schematic capture and PCB layout
147 * [GCC](http://gcc.gnu.org/) compiler and source debugger
149 * The hardware is licensed under the [TAPR](http://www.tapr.org) [Open Hardware License](http://www.tapr.org/ohl.html)
150 * The software is licensed [GPL version 2](http://www.gnu.org/licenses/old-licenses/gpl-2.0.html)