What is the status of keyid & associated data fields ?

[touilleMan]

Hi,

I come from https://github.com/RustCrypto/password-hashes/issues/261#issuecomment-1009781776

It seems keyid & associated data fields have had a rough life (see #173 and #143), so from what I understand:

• keyid is not part of the argon2 algorithm, it is only a field that was once part of the hash encoding format
• associated data is part of the argon2 algorithm
• keyid and associated data fields are no longer handled by the hash encoding format (and libsodium implementation does the same thing )

So my questions:

• is there an official document about the hash encoding format ?
• is it the correct to not handle keyid and associated data fields in the encoding format (our current implementation handle them, so this may lead to incompatibilities if hash generated by our lib get verified on another implementation)
• is the keyid field officially deprecated (or even abandoned as it has never been really used ?)
• what is the status of the associated data field ?

[tarcieri]

is there an official document about the hash encoding format ?

The closest thing I'm aware of is the PHC string format specification:

https://github.com/P-H-C/phc-string-format/blob/master/phc-sf-spec.md#argon2-encoding

[Leont]

I'm having the same questions. I remembered them and wanted to use them and now came to the unexpected conclusion that they're gone.