A Few Common Sense Precautions
- Don’t fall into the false sense of security trap
- Authentication does not equal security – it is only one part of security
- Do you really KNOW that person, or is it just someone on the radio or on the internet?
- Never share your private codeplugs through any publicly accessible means
- Be prepared to switch to a new set of codeplugs in case one set is compromised.
Download and Install
MsgAuth main web page – https://kf7mix.com/msgauth.html. You’ll also find a YouTube video about the program on that page.
Setting Up Your MsgAuth Configuration File
You really only need one codeplug, since you only use one at a time. Being able to switch them around adds a big extra layer of security to the authentication process. This walks you through the steps of creating a block of codeplugs.
Although you could just start entering a series of “random” numbers, the human mind really doesn’t handle that task very well. Using a random number generator makes it fast and easy – and truly random.
➊ Go to https://www.random.org/sequences/
➋ Generate a list using numbers 1-99. Repeat to get more codeplugs. (repeating 3 times will get you 20 codeplugs of 15 numbers each if you add a few to the last line)
➌ Copy and paste those 99 random numbers into a text editor. Make sure there is no blank space preceding the numbers.
➍ Go through the list and add a zero in front of each single digit number. You may want to press the Insert key on your keyboard to make this easier.
➎ Go through the list and add random “+” or “-” after each number.
➏ Go through the list, pressing End, then Delete to form a continuous string on one line. Go through the entire list until they are all on a single line.
➐ Break up the line into strings with a minimum of 10 number/sign groups (more is better – 15 is probably a good number). Make sure there is a “+” or “-” at the start of each line, but not at the end.
➑ Add two blank lines above the first code plug line.
➒ On the first line, enter “light” or “dark” depending on your preference for the appearance. On the second line enter your call sign.
➓ Save the file, and name it msgauth.cfg . Move the file into your msgauth folder and replace the existing sample file.
Suggestion: At the end of the msgauth.cfg file, add one line that will be used strictly for testing and practice. This a codeplug that anyone can use for practice, so you don’t compromise your “real” codeplugs. All practice exercises and examples on this site use the following as a practice codeplug:
-99-98-97-96-95+94+93+92+91+90
Changing Codeplugs – Another Layer of Security
Only one codeplug is used at a time, so that is all you need to use the program, but good security practice calls for having multiple codeplugs and the ability to switch between them as needed. We’ll go over a few methods for you to consider, but we need to start of with a quantity of codeplugs to use. The steps above will get you about 20 random codeplugs to work with.
Month Number Method – This requires a minimum of 12 codeplugs, and the first number in each codeplug will be a month number, so the codeplug starting with 01 is used in January, 02 is used in February, etc.
Modified Month Number Method – This is basically the same as the Month Number Method, but uses a less apparent pattern. You can get creative with how you do it, but some examples are: Month number plus something. For example, month number plus 8, where January is 9 (1 + 8), February is 10 (2 + 8), etc.
Position In List Method – Everyone in the group has the same block of codeplugs, and each codeplug is completely random. Pick a time to switch (Day of the week, Date, Month, whatever you want to use), and have each person count down their codeplug list to the one needed. This works because MsgAuth always starts with the top codeplug on the list. A variation on this is to simply transmit (or speak) the position on the codeplug list as part of the authentication message, or slip the codeplug position elsewhere in the message exchange.
Backup Codeplug Blocks – Everyone in the group has their normal block of codeplugs that is part of their msgauth.cfg file, but in addition, they also have one or more additional random codeplug blocks (each person in the group, of course, has the same set of codeplug blocks). The main use for this is being prepared in case the primary set of codeplugs gets compromised. This would typically be used in addition to one or more of the above methods.
