I am told that FLE-related specifications do not specify the preferred spelling of "encrypter"/"encryptor". It seems Python and Node use "encrypter" in their libmongocrypt bindings, while Java uses "encryptor".

These are not part of any public API, but for consistency between drivers and ease of code searching, I would expect the team to arrive at a preferred spelling.

"Encryptor' appears to be more popular in literature: https://books.google.com/ngrams/graph?content=encryptor%2Cencrypter&year_start=1800&year_end=2008&corpus=15&smoothing=3&share=&direct_url=t1%3B%2Cencryptor%3B%2Cc0%3B.t1%3B%2Cencrypter%3B%2Cc0