Is there an existing authorative definition of the cryptographic term 'pepper'
I have found one source that claims to have invented the word &quot;pepper&quot;.
-- But this doesn't mean that they were the first or the only inventors. I guess it may have been invented and reinvented several times.
1999 Paper
Kedem, G., &amp; Ishihara, Y. (1999, August 23-26). Brute Force Attack on UNIX
Passwords with SIMD Computer. Paper presented at the 8th USENIX Security
Symposium, Washington, DC.
They invent &quot;pepper&quot; on page 6 like this: (line breaks added for readability)

The main idea is to add random bits to the password encryption, similar to the “salt” bits that are currently used to protect passwords against dictionary attacks.
We call the new bits: “pepper” bits. Unlike the “salt” bits that are saved with the encrypted password, the pepper bits are used to encrypt the password, but are never saved.

But I think there are likely to be many different definitions of the term &quot;pepper&quot;, simply because people know what &quot;salt&quot; is and like to extend analogies.
I don't think K&amp;I's 1999 definition ever really caught on. To me at least, &quot;pepper&quot; is a cryptographic secret, that is stored but stored somewhere else than the salt.