So much has been written by greater minds than mine about secure communication in a crisis. There are many publicly available resources and information on SurvivalBlog and elsewhere.
Shifting letters in a message a certain number of characters is nothing new (Caesar Cipher, used in the last century B.C.). Using the SAME count to shift letters is a guaranteed way to have your encryption broken. Using different numbers to shift each letter in a message (a One Time Pad) – when your recipient has the same list of numbers to decrypt the message – is theoretically unbreakable, if you do it right.
This approach will only work if you have a list for the sender and a list for the recipient that is truly random. You can copy blocks of random numbers from several websites on the Internet [probably risky], or you can pretty quickly make your own table of random numbers with 10-sided numerical dice. Like this:
https://www.amazon.com/Chessex-CHX25408-Dice-Opaque-Black-White/dp/B077YC6JY1
This spreadsheet below (SFGshift) has been built to shift letters in a message. You type in the letters of your message, one letter per cell vertically, then you type in the numbers from your block of random numbers vertically. And the spreadsheet outputs letters that have been shifted the correct amount. Write down the encrypted letters and send that, either by email, or texting, or reading it letter by letter over the radio, or any one of several other methods.
When you’re done, you can select those two columns (message and numbers) and delete them, or just don’t save your changes when you close the spreadsheet, so the spreadsheet is clear for your next message. You can do the letter shifting by hand, of course, it’s just maybe a little faster to get your computer’s help (I wouldn’t do so on a computer connected to the Internet…). Or you can use a wheel like this:
https://www.giftofcuriosity.com/secret-codes-for-kids/
The spreadsheet here:
…can shift letters any number of characters, but for simplicity’s sake, I recommend simply using SINGLE digits from your block of random numbers.Continue reading“Using Effective Encryption, by ShepherdFarmerGeek”
