Post by: Dennis on August 16, 2012, 03:11:56 am
I'm working on a CSPRNG (cryptographically secure pseudo-random number generator) for the Digispark. At the moment I do some testing on measuring random data with my UNO.
My project is still at the beginning, but I'd like to give you some information on how my CSPRNG will be working.
1. Measure (more or less) random data with the Digispark. (Unfortunately the analog inputs noise (without sensors attached) seems to be pretty deterministic. So I have to consider another solution.)
2. Using the "random" data as an input for some cryptographic functions. My Beta1 will be using an improved Version of RC4 (which is often used as a CSPRNG). I will have a pretty detailed look on RC4 in this environment and maybe use another algorithm in later releases.
3. After calculating a new key the Digispark will act like a keyboard and type the key into any typing field you want. This is where I need your help. Unfortunately the example keyboard libraries are not working in my UNO. Does anyone who know how I get my UNO to act like a keyboard?
Dennis
ps. To achieve Kerckhoffs principle I'll publish my source code once the detailed testing is done.
Post by: bart on August 16, 2012, 05:32:25 am
I\'m planning to do a similar thing after seeing http://youtu.be/kpNSycoUCZM (you should be able to build this with a digispark).
Getting the caps-lock info should not be to hard ( http://youtu.be/jOUbEna4lNs ) so taking time in between key-presses should give me enough random input.
/Bart
Post by: sparr on August 16, 2012, 02:14:42 pm
Post by: Dennis on August 16, 2012, 02:15:57 pm
I decided not to use key-board pressing as an input since it is extremely deterministic. But how do I get my UNO to write sometime like a keyboard?
Post by: digistump on August 16, 2012, 05:21:56 pm
Post by: bart on August 17, 2012, 03:42:48 am
@digistump - nice one! have hot seen that one before!
my \"Arduino + keyboard\" links:
http://arduino.cc/en/Tutorial/KeyboardMessage (Leonardo only? not UNO?)
http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1226896251/ (\"analog\" keyboard)
Post by: MichaelMeissner on August 17, 2012, 05:17:20 am
Post by: bart on August 17, 2012, 08:48:23 am
http://codeandlife.com/2012/03/03/diy-usb-password-generator/ shows that it is also possible with an ATtiny85
What brings me to the next question: in the 2k boot code, is there anything foreseen for a usb-keyboard?
Post by: Dennis on August 17, 2012, 08:56:16 am
@Erik: Thank you. I\'ll have a closer look at this page.
Project update:
Today I got some sensors. Unfortunately they provide pretty accurate data. I need to find another way to achieve a random input. Maybe I\'ll have a closer look at measuring the noise of an ADC channel with no wires attached.
Post by: Dennis on August 17, 2012, 09:57:51 am
This would be a pretty good source for true random numbers, but a way too expensive. :-)
Post by: sparr on August 17, 2012, 10:22:16 am
Post by: Dennis on August 18, 2012, 04:45:26 am
Project update:
I decided to keep my current circuit. Without using them as an RNG, but to add some temperature- and light-dependent inputs. Which means, that even if you are able to recover the random input, you have to run the Arduino under the same conditions (light and temp) to get the same key.
Here is my beta circuit diagram (nothing new for experienced Arduino fans, but maybe interesting for newcomers):
![\"Bild](\"http://www.pic-upload.de/view-15654087/PasswordSpark-V1.jpg.html\")
Post by: crabbypup on August 21, 2012, 06:33:42 pm
or make a very high-gain antenna and use an OP-AMP to turn EMI into pseudo randomized binary.
Post by: Dennis on August 28, 2012, 08:30:01 am
Project update:
My current algorithm works pretty well. Next step will be using RC4 for better statistics.
Post by: mgrennan on December 20, 2012, 08:44:17 am
Runs on 2.0-5.5V
Integrated capability for both host and client operations Superior SHA-256 hash algorithm, HMAC option Best-in-class, 256-bit key length; storage for up to 16 keys
Guaranteed unique 72-bit serial number Internal, high-quality Random Number Generator (RNG) 4.5-Kbit EEPROM for keys and data 512 OTP (One Time Programmable) bits for fixed information.
The idea will be to create a crypto pair. You carry one. To use it, you plugin the \"Public\" device, touch it, and it will type a one time password that only it\'s \"Private\" device can de-crypt.
This could also be used as part of authentication control lines to remote equipment like radio transmitters or manufacturing equipment. A ATSHA204 could be wired into a laptop or a software only version could be coded into ... ? The BIOS so only the \"Public\" key could decrypt the hard disk? I guess I said it all with OTP.
Post by: Daleeburg on December 26, 2012, 03:11:49 pm
https://www.sparkfun.com/products/11345
:)
I know, not exactly cost efficient
Post by: Bluebie on December 27, 2012, 05:06:37 pm
Post by: Dennis on January 13, 2013, 06:05:44 am
Sorry for my delayed update! But there\'s some progress I want to share with you! I\'m working on an Implementation of SHA-3 (Keccak) on one of my µControllers. Once I received my Digisparks I\'m going to port my code to them. I think SHA-3 is a great mixing function.
Post by: Coterabeth on January 27, 2013, 04:03:13 pm
Post by: Bluebie on March 05, 2013, 06:24:38 pm
Digispark has all the needed hardware - It just might take a little tweaking to get it working well on the digispark - some registers maybe a little different. Let me know if you need any help adjusting it.
One adjustment which should be made is to change ISR(WDT_vect) to ISR(WDT_vect, ISR_NOBLOCK) - this change will let you use DigiKeyboard, DigiUSB, or other digispark usb libraries without having the watchdog timer stomp all over the USB driver and break the connection.
Post by: iocon on March 10, 2013, 11:18:35 am
Currently I have not been able to get the keyboard feature to work on boot. The provided library specifically says it does not include these features.
I revised the descriptor with a known working one and implemented the changes for handling keyboard LEDs and (usbFunctionWrite).
changes in usbdrv.h, usbconfig.h were necessary.
I'm stuck getting the DigiKeyboard class to work after making those changes though. I modified usbFunctionSetup to handle the extra types based on the same working code, and everything builds and runs (I have an LED indicator to be sure it's running that stops right before it sends the keys) but it won't send keypresses.
Has anyone made a library with boot support? Any Ideas?
Post by: defragster on September 07, 2013, 04:35:07 am