I'd like to write a D&D/OSR spell, need advice for fantasy themes/tropes and if something similar already exists.

I'd like to make a spell that hides a secret or piece of intel from discovery, be it divination or record (memory, text, etc.) I'd like to hide my character's true name and replace it's knowledge in game with a pseudonym. The idea is to protect it from those who already know it or may seek it, to abuse with powerful magic. I'm not sure if a similar spell may already exist, and if not what kind of classic fantasy tropes or symbolism may be involved in keeping/uncovering said secret intel. Does anyone with XPerience or anything have suggestions?