wtf is argon2?

The argon2 package lets you hash passwords securely in R. Hashing transforms a password into an scrambled string that you can safely store in a database, so that if someone steals your database they still can't recover the actual passwords. This matters because users reuse passwords across services, and a breach in one place shouldn't expose them everywhere. Here's how it works in practice. You call pw_hash() with a password, and it returns a long encoded string. You store that string wherever you keep user records. Later, when a user tries to log in, you call pw_check() with the stored hash and the password they entered. It returns TRUE if they match and FALSE if they don't. The package also includes a wrapper for blake2b, another cryptographic hash function useful for digest authentication. The argon2 algorithm itself is a relatively recent design recognized by the Password Hashing Competition, and it's considered very secure against modern attacks, including those using specialized hardware. The package bundles the reference implementation from the algorithm's original developers. Who would use this? Anyone building an R application that needs user authentication, a Shiny dashboard with login, an API with protected endpoints, or a research tool that restricts access. If you're storing passwords in a data frame or database and need to verify them later, this package handles the cryptography for you. The README notes two related R packages, sodium and bcrypt, for similar needs. One detail worth noting: if you build from source, you can enable CPU optimizations with a configure flag that speeds up hashing. The author couldn't make this the default due to CRAN policy constraints, so users who want maximum performance need to compile locally rather than installing from the standard repository.