Intro: Build an Electronic Random Character Generator for One Time Pad Cryptography
Foil the NSA! With this device you can make One Time Pads and create cryptograms that are unbreakable if used correctly. The concept is simple. Create a string of random characters (that is where this device comes in). Share this string of random characters with a friend. Use the random string to encode a message. Your friend can decode the message using the random characters you shared earlier. If the random string is kept secret, it is theoretically impossible for anyone but you and your friend to read the message.
Don't wait! Get your One Time Pad generator here!
Step 1: Add the LEDs to the Board
To start, let's add the LEDs to the board. Start with the four corner LEDs. Once those are soldered add the rest, row by row. Each LED has a flat side which should be aligned with the white outline on the board. I have made it very easy for you since all the LEDs are oriented the same way :). Use a wire cutter or low profile trimmers to clip the leads flush with the board. The green ones shown in the pictures are from the craft section at Wal-Mart and work great.
You should now have 15 LEDs soldered and oriented correctly. It is important that they face out straight to match the holes in the case.
Step 2: Add the Coin Battery Clip
Adding the battery clip is easy. Place it on the board with the curved edge facing the outside. It should match the outlines on the board. You may find it helpful to temporarily tape the battery clip to the board while you turn it over to solder the bottom side. A quick dab of solder on one terminal while you hold the clip in place works too.
Step 3: Adding the Microcontroller
The microcontroller is the last component to solder. Be sure the end of the microcontroller with the dot is aligned with the white notch of the outline on the board. Double and triple check it is oriented correctly before you solder.
Step 4: Add Battery
Insert the supplied CR1225 battery (positive side up) into the battery clip. Your One Time Pad Generator is now ready!
Step 5: Touch the Sensor to Generate a Character
Just touch the sensor at the top of the board with a finger to start random character generation.
The kits will sleep in low power mode until another touch is sensed.
If you ordered a kit with a case, you will need to extend the touch sensor