Secure communication for preppers

Array

32 Shares
man writing letter

Have you ever considered how you would communicate covertly and/or securely if the need were to arise? It could be for a number of reasons; maybe you simply don’t want someone to know what you are talking about or maybe it is more serious and electronic communications are not functioning because of an EMP. The modern technology that the United States, as well as foreign, governments possesses allows the easy electronic surveillance of almost anyone. This could be a good reason by itself to have a way to communicate in a nontraditional, but secure way. One of the longest-standing ways of communicating in a secure and covert manner is through written code, also known as cryptography.

While seemingly only something you would see in a movie, from a historical perspective, cryptography has played a huge role in wars, diplomacy and, of course, espionage. Meaning hidden or secret writing in Greek, cryptography is the practice of taking clearly understood text and converting it into a state that is not understood except for the person who holds the key needed to decrypt the code. This could be a valuable tool to use within a prepper group or in an extreme case such as a future conflict within our own borders. Realistically speaking, cryptography can be useful in any situation where two parties wish to communicate with one another without anyone else being able to decipher what they are saying. In addition to being a more secure manner of communicating, cryptography can be used with any means of communication — verbal or written.

Whether verbal or written, a prepper can use encrypted messages in a variety of ways to avoid information compromise. A radio that is unsecure like a family band radio or CB can be dangerous if sensitive or personal information is being shared. Also, email or online communications are at risk of being captured or intercepted by law enforcement or intelligence agencies. Leaving a message in a meeting location (especially in public) or dead drop is not secure. All of these methods carry risk; and with so many opportunities for your information to be compromised, you should communicate securely with encrypted messages.

There are several types of codes or ciphers that can be utilized in cryptography and while it can be a personal decision to decide which type to use, there are specific benefits to using one over the other. With that being said, there are a variety of methods in which messages can be encrypted but the most basic of these methods is to use a cipher. The difference between a code and a cipher is that a code is the process of substituting a word or set of words for another, where a cipher plainly changes each letter in a word into another letter or number. The decision to pick one over the other typically comes down to how secure you would like your message to be.

Types of cryptography

Code: The simple process of changing one word for another complete word or set of letters. An example of a code could be taking the words “breakfast cereal” and substituting them with the words “flat tire” or a specific set of letters that are unique to “breakfast cereal.”

Transposition cipher: Rearranging the order of the letters in a message. An example of a transposition cipher would be taking the words “medical kit” and converting them to “lcaiedm tki.” This is typically the most basic and simple cipher.

Substitution cipher: Systemically replacing specific letters or groups of letters in a message. An example of using a substitution cipher would be taking the words “gun range” and by shifting each letter back two letters (-2) in the alphabet, changing them to “esl pylec.” As you can see, this is different than just shuffling the letters in a word or phrase around but also can produce a pattern that can more easily be decrypted.

When looking at your options, also remember that with either a code or cipher you will have to have some sort of record or idea of how you will decode your message. Either way, having such a record could be a potential risk and increase the chances of compromise. Because a code is fairly simple, I will leave that up to you and only describe how to develop a cipher.

Developing a cipher

It is not the most difficult thing in the world to develop a cipher. In my opinion, the transposition cipher is not as secure as the substitution cipher for I will allow you to develop your own transposition cipher should you choose to. I prefer to take a two-pronged approach to the substitution cipher where a separate encryption is used for consonants and vowels. This might look something like this:

  • Consonants: The set of letters in the alphabet that are not vowels are consonants. To keep things simple, use the encryption of +5 letters and count without excluding the vowels from your count. You can make it your own but I will include the vowels in this scenario for ease of use. Using +5, a letter C will become the letter H and the letter Z will become the letter E, etc.
  • Vowels: Take the vowels A, E, I, O, and U and determine what interval you would like to use. If you were to choose a +1 interval, move ahead one vowel from the actual vowel in the word. With this being the case, an A becomes an E, an E would be an I, and so on and so on. If you chose a +3 interval, the A becomes an O and the E becomes a U.

You might notice that in these examples if you have a letter toward the end of the alphabet, it may become necessary to move to the beginning of the set of letters and keep counting. It is also important to keep in mind that a cipher does not have to always move to letters to the right (or plus letters), you can also move to the left (or minus letters).

Let’s look at the example below for a better understanding using the same variations listed above (+5 for consonants and +1 for vowels):

Using the phrase, “My favorite soda is Mountain Dew” as the sentence to be encrypted and applying the cipher, the phrase now becomes “Rd keauwoyi xuie ox Ruasyeos Iib.”

It is prudent to shift or change the cipher so that security is best maintained. A different day should have different encryption to avoid demonstrating a clear pattern and getting your cipher cracked. What will read one way on a certain day will likely look completely different on another day. Monday could be a +1 shift for consonants and a -1 shift for vowels. It is totally up to you and your imagination. Don’t forget about numbers either. You may need to include numbers in your communications and should select a specific variable for numbers just like you did with the vowels and consonants.

I personally like the idea of a four-week rotating cipher that uses two prongs: one for the consonants and one for the vowels, as outlined in the demonstration above. The thing to be careful about is making sure that your rotation does not become routine or predictable. You can do this by continuing to shift the variables back and forth using both negative and positive intervals. The table below will provide you an idea of what this might look like:

graphic1021315

There technically is probably a limit to the combinations that you can use, but there are enough combinations that I was not worried about trying to count them all. My point is that you can pretty much do whatever you want when designing your cipher. To make things even easier, a quick reference card or chart can be made to facilitate quick decoding and coding of messages. Obviously, you must be careful to never allow the key to the cipher and your reference to be kept together if you have both because it will completely defeat the purpose.

Here is an example of a reference key:

graphic2021315

There are a few other methods of cryptography that can be used to make a message secure but they are not all probably as secure as a cipher. They can be simpler though. If we use our example sentence from before and placing each word as the fifth word in the sentence, you can encode your message in a paragraph. I would look something like this:

How do you like MY new scarf? I can’t believe your FAVORITE is green! I think that a SODA will quench my thirst. There’s a chance I IS going to flunk English class when I talk like this. I saw a huge MOUNTAIN off in the distance. Grass is covered in DEW early in the morning.

While I chose to place my message as the fifth word in each sentence, you can just as easily vary the options by making the operative word variable in each sentence. Such a sentence might be something like the operative word in the first word in the first sentence, the second word in the second on so on. This could also be reversed. Once again, imagination is the only limiting factor.

A book can be another method used to code and decode messages. The key is just that the book has to be common to the parties involved. Really, any book that all parties have can be used by simply recording the page number, the line number on the page and the specific word on the corresponding line. An example might be the words “food storage,” which might be listed on page 42 on line 12 with word 5 being the word you need. This would be recorded as 42 12 5 and then a space is inserted before the next word. Imagination can have full reign here as well. You could use any number and type of book.

It is easy to see how dealing with cryptography can be a little difficult. And while communication can become more difficult through the use of cryptography, you run less risk of revealing sensitive information and putting life and/or property at risk.

When it comes to cryptography, the older and less technical codes and ciphers seem to be the most compatible for use within a prepper group or circle of trusted friends and family. The more modern ciphers typically rely on advanced mathematics, algorithms and computers, making them less practical for preppers in most scenarios. Could you imagine trying to decode a message that required a computer without an electricity source? It is just for reasons like this that a basic but well thought out cipher can be the best selection for the prepper.

–Thomas Miller

Personal Liberty

Thomas Miller

lives with his wife and three sons on an island in the Pacific. He loves fishing, woodworking, hiking, swimming, golfing, and generally anything that he can do with his family. Using his skills and knowledge acquired in the Army, honed through multiple combat deployments, and gained through the ongoing study of survival and preparedness, Miller shares his knowledge and thoughts on his blog, thepreparedninja.com. You can also connect with him on Twitter, @preparedninja.