Presumably you took your role name and encrypted it, and there's a key for that, for a normal newspaper cryptogram that key would be what each letter in the cryptogram was, like a=g, b=f, etc. If you used the add a word method I detailed, then the key is the word you used, Tracker+Helium=YourCode, with Trackers as your role and Helium as your key. Basically encoded word (role) plus key = code. Doesn't have to be addition of course or words, that's just the easiest and least ambiguous route I could think of to suggest, you could for instance have converted your role into numbers (a=1,b=2, etc) then multiplied the entire thing by your year of birth, in which case the key would be your birth year. In cryptography, a key is what defines the output of a cipher. The thing you want to encode, the plaintext is converted to the code, the ciphertext by taking the plaintext through a cipher, a process of encryption, which is usually some mathematical process dependent on a key.

Example
Plaintext: TRACKER
Key: HELIUM
Cipher: Convert plain text and key to numbers, add them together, convert back to letters
Cipertext: BWMLFHR

In detail:
Tracker + Helium = BWMLFHR
20-18-1-3-11-5-18 + 8-5-12-9-21-3-0 = 28-23-13-12-32-8-18
Change the 28 and 32 into 2 and 6 (28-26 and 32-26) and you get
2-23-13-12-6-8-18 or BWMLFHR

Sidenote: Actually the cipher should say "add them together with a modulus of 26", modular arithmetic, which we do with clocks, is where 8+12=8, or "It's 5 now, in 10 hours it will be 3 o'clock", when adding letters converted to numbers, "Mod 26" is generally the default, a=1, b=2.... y=25,z=26,a=27, b=28 etc

So, basically, we don't really need a key, we need people's ciphers, just most of the simple but solid encryption methods tend to have a key, and one with a key that's a word is much more believable then if someone's cipher is some random number string, since you can make any darn word you feel like that way.

Hope that helped