SparkFun Electronics Commentsurn:uuid:214d0e4e-f1b1-d287-ce26-ac5b4c9f82492024-03-29T03:57:54-06:00SparkFun ElectronicsMiskatonic on Getting started with Arduino cryptography Miskatonicurn:uuid:1f0af872-7275-d783-3716-206a9f27979f2018-04-26T12:05:31-06:00<p>Cool! if you have any sample code, I'd love to tinker with it!</p>
jma89 on Getting started with Arduino cryptography jma89urn:uuid:98791ff3-7cc2-edc6-1399-6383b405066d2018-04-26T10:17:17-06:00<p>There is an easy way to do programmatically simple "encryption" that's uncrackable: A <a href="https://en.wikipedia.org/wiki/One-time_pad" rel="nofollow">one-time pad, or OTP</a>.<p>Basic gist: Have a single-use random string that's the same length as (or longer than) the message you wish to send. Take your original message, add the OTP to it (per-character), and then MOD 26 the result (again, per-character. The Wiki page has a great example section for this.)</p><p>Only downside is that the security of a OTP comes from the secret never crossing an insecure channel. You could preload the entirety of spare flash with a massive (or several smaller) pads, then mark in EEPROM when they get used. (The base station would similarly keep track of this.)</p><p>Once all the pads are used up you'd have to re-compile (with new pads) and flash your transmitter again. Bonus points for just using a "small" (~8 GB) SD card instead and filling it with pads. Even if you did use them all it's just a matter of swapping in a freshly filled card.</p></p>
dbvanhorn on Getting started with Arduino cryptography dbvanhornurn:uuid:1587fbda-cc70-aa4b-0a6d-fce172a4787f2018-04-25T18:06:00-06:00<p>Cool!<p>I wrote an enigma machine for the AVR back probably 2007 or so. I had just finished a print cartridge system for a client that used multiple wires for communication. I only needed two, but they had designed in eight, so I set up my comms on two lines and fed digital noise down the other lines, and radically changed the comms speed (clocked serial) so as to frustrate a logic analyzer attack, then I started changing which wires I was using to communicate every so often, and finally encrypted the data that was running over the link. I don't think it ever got hacked. Paid the bills... :)</p><p>The enigma is still a pretty cool little beast. Brute force cracking it is still rather difficult.
http://www.bytereef.org/m4_project.html</p></p>
Miskatonic on Getting started with Arduino cryptography Miskatonicurn:uuid:639e7d77-d38e-51f4-8ae3-14f9e7943dc62018-04-25T13:33:07-06:00<p>Yeah, If it isn't clear from the post, this is a teaching tool. Don't use it for anything you can't afford to have hacked.</p>
Customer #200138 on Getting started with Arduino cryptography Customer #200138urn:uuid:57b9f9a4-a8d5-eef1-c1e2-bb8748e0cb9a2018-04-25T13:24:53-06:00<p>yep. This algorithm discloses one "secret" value at a time for anyone listening to the exchange. Equivalent to just sending one value of the array at every transaction. Wait a couple of exchanges, and you have already enough values to be able to respond to a challenge.<p>The best security algorithms are the one you do not design on your own...</p></p>
Customer #394180 on Getting started with Arduino cryptography Customer #394180urn:uuid:7994c9c0-51dc-3173-7819-6facaa0a97682018-04-25T09:56:05-06:00<p>You should add a big disclaimer to this article to not even think of using this algorithm for actual security. While it's a nice demonstration and fun toy, it's trivial to crack and anyone who actually uses it, especially over the internet, is going to get no protection at all.<p>I can just see an inexperienced person trying to add security to an IOT app running across this and being overjoyed since it's so much easier to understand than a lot of other examples out there.</p></p>