JeanaByte walks us through how she would solve the Summer Camp 2020 – Cryptography challenge: Numeric.

For numerical cryptography, I always like to use this handy dandy chart (created by Kait) for teaching how to identify the different number bases.

Base-n	Characters Found in Encryption Type
Base-2 (binary)	0, 1
Base-3 (ternary)	0, 1, 2
Base-8 (octal)	0, 1, 2, 3, 4, 5, 6, 7
Base-9 (nonary)	0, 1, 2, 3, 4, 5, 6, 7, 8
Base-10 (decimal)	0, 1, 2, 3, 4, 5, 6, 7, 8, 9
Base-16 (hexadecimal)	0, 1, 2, 3, 4, 5, 6, 7, 8, 9, a, b, c, d, e, f
Base-36 (alphanumeric)	0-9 and all lowercase letters
Base-62 (sexagesimal)	0-9 and all capital and lowercase letters
Base-64	0-9, all capital and lowercase letters, + and / (Usually ends in “=” or “==” which is padding)

This is definitely the easiest way to identify number bases if you’re new to numerical cryptography, and honestly, even if you’re not new to it this chart seriously comes in handy.

To identify the number base, find the “highest” single digit. Sometimes the highest digit is a letter! But note, it can always be a higher number base than the highest digit. It will just never be lower.

All you need to do once you’ve identified which number base you’re dealing with is look up number base decoders that will decrypt into text and input the encrypted text.

Pro Tip: Make sure you are “encrypting” or “decrypting” as appropriate. If you can’t read the message and want to, make sure you use the “decrypt” settings on these tools!

Have fun and happy hacking!

JeanaByte