Argon2ds

Argon2ds is a variant of the Argon2 password hashing function. Argon2 itself is a key derivation function designed to be resistant to hardware-accelerated attacks, making it suitable for storing passwords. Argon2 comes in three main variants: Argon2d, Argon2i, and Argon2id. Argon2ds is a hybrid version that combines the strengths of Argon2d and Argon2i.

Argon2d is designed to be highly resistant to time-memory trade-off (TMTO) attacks by maximizing data access parallelism. However, this parallelism can make it more vulnerable to side-channel attacks, particularly cache-timing attacks, if not implemented carefully. Argon2i, on the other hand, uses a different memory access pattern that is more resistant to side-channel attacks but may be slightly less resistant to TMTO attacks compared to Argon2d.

Argon2ds aims to provide a balance between these two. It incorporates the data-parallelism of Argon2d for improved TMTO resistance while also incorporating some of the side-channel resistance techniques found in Argon2i. This hybrid approach offers a robust defense against various types of attacks. The "s" in Argon2ds stands for "side-channel resistant," indicating its focus on mitigating these vulnerabilities. When choosing a password hashing algorithm, Argon2id (which is the standard recommended variant and is effectively Argon2ds in practice) is generally considered the best option due to its balanced security properties against both brute-force and side-channel attacks.