argon2* functions don't accept version. Instead it is hardcoded as ARGON2_VERSION_NUMBER. Should this lib support multiple versions?

[KOLANICH]

It may cause issues if/when this lib has to have the hash function version upgraded. If a certain version of Argon2 was used to hash secrets, the same version would have to be used when the same result is expected. This way, upgrading Argon2 version in this lib would cause breakage of the software depending on it. The proposed way to deal with it is

1. add version field to argon2_context, and initialize it with ARGON2_VERSION_NUMBER by default.
2. deprecate the current set of functions, leave argon2_ctx or maybe a new wrapper around it as a recommended method of doing hashing.
3. state, that the current set of functions use the current value of ARGON2_VERSION_NUMBER. Put it into ARGON2_LEGACY_API_VERSION_NUMBER, while ARGON2_VERSION_NUMBER is free to be incremented.
4. implement all the versions of the functions and dispatch based on version field.

Users using the legacy API are free to do it. Users using the new API are expected to set version field of the context object to the version they expect/store it somewhere for future use.

[jedisct1]

Use the documented, high-level functions: crypto_pwhash_*().

[KOLANICH]

Thanks for the info.