I am looking to use an encrypted field as an external ID for the upsert function. As long as the user running the upsert has read access, the fact that it ID for the upser is encrypted shouldn't matter, correct? I want to make sure that when I try to upsert, it wouldn't see an encrypted value, as compared to the text value.
For example, if I wanted to encrypt last name using case-insensitive encryption. Then, I wanted to upsert based on last name, would it see 'Smith' to perform the upsert? OR would it see the encrypted value?