I just tried to picture it and burst out laughing. Would you be able to provide any more details about this deposition? In what context did one-way hashing come up?

One way hashing came up in the context of sharing email opt-outs without sharing the actual email addresses. (Send a list of hashes of email addresses and the hash function and require that no one whose email hashes to a value on that list may be emailed marketing material.)

It's been many years now, but we did some canonicalization of email addresses before hashing [downcasing, stripping whitespace, stripping periods (gmail), stripping any local tags (plus-sign), and maybe a few others I'm forgetting] since false positives were "safe".

Sounds like a joke straight out of Rick and Morty, got a laugh out of me!

That's hilarious but did the comment even need a reply?

No; counsel was clearly stopping and waiting for me to respond. I could have remained silent, but my reply was a way to move things along (by indicating I wasn't going to ramble in response to a non-question as well as getting a poke in).

Haha I see, thanks!