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  • Google is slowly phasing out google talk. google talk client on android is no more. So much for federated and open instant messaging... Fri May 17 @ 7:13 PM

Pig Identification Guarantee

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Mar 192013
 

3 Years ago I worked for a client who made use of the RSA Securid system. I was amazed by it. It seemed to add so much security to the systems I was accessing with it. I even liked watching the numbers turn over on the token feeling like a spy. I looked into setting it up for my own personal servers, and I was disappointed when I found out it was financially restrictive. It also frustrated me that I could not maintain the shared secret myself. Letting RSA authenticate my personal laptop was not going to work for me. Especially when it was disconnected from the internet.

I began to look into other two factor authentication solutions that where free software. And I found a few, Perfect Paper Passwords, being one of the more complete solutions. But carrying a sheet and updating it constantly was not a security token. So I began trying to figure out how the RSA tokens worked. I came up with a way of hashing and rehashing a secret on an arduino and then verifying it on my laptop.

/wp-content/uploads/2013/03/wpid-7disp_token1.jpg

It worked great, but not a real solution as an arduino isn’t battery powered or sits comfortably in your pocket. Tim Heath and I started work on the hardware design two years ago. Neither of us had any experience in electronics so it was pretty surprising when our first board functioned.

/wp-content/uploads/2013/03/wpid-pig_rev0.jpg

In between a few of our prototypes Google Authenticator was published. From that I found out about this rfc4226. It made me feel stupid that I had implemented this part of the protocol from scratch. But happy that it matched an IETF standard.

Below is a prototype of our current working design.

/wp-content/uploads/2013/03/wpid-pig_breadboard.jpg

It led to the building of this

/wp-content/uploads/2013/03/wpid-pig_prototype.jpg

Dustin Clark has also built pig client token code for android

/wp-content/uploads/2013/03/wpid-pig_android.png

and iphone

/wp-content/uploads/2013/03/wpid-pig_iphone.jpg

pdf describing the protocol in full in this white paper

programming avrs

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Feb 082010
 

I have been working on avr project for almost a year now.  As I have been getitng closer to completion I have finally jumped from arduino to my own custom avr board.   Then came the problem of programming the icsp.  I tried 2 different serial and parallel programmers to no luck.  And then I thought why not use an arduino to programmer to program my avr 168p.  I tried 4 different software ones to no luck and then found this mega-isp  . works great,  I was able to flash my avr with no troubles I highly recommend it.

working with avr and pwm

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Feb 062010
 

I seemed to have a lot of trouble getting pwm code going.  below is some simple code that got me going.  looking back on it now I am unsure as to why I was having such problems.  I think its because, arduino, port codes, and timer codes, and pwm codes dont exactly match and I wasnt looking at the reference material.  anyways hope this helps.


int main (void)
{
        DDRD |= (1<while (1)
        {
                asm("nop");
        }
}