Yescrypt

Yescrypt is a cryptographic key derivation function designed for password hashing, created by Alexander Peslyak, known professionally as Solar Designer. It builds on the earlier scrypt algorithm and is engineered to resist hardware accelerated brute force attacks by requiring substantial memory and by processing that memory in a strongly sequential way, which makes the workload difficult to parallelize on GPUs, FPGAs, and ASICs used by attackers. Because of these memory hardness properties, yescrypt offers stronger practical protection than older schemes such as SHA-512 based hashing, since cracking large numbers of hashes in parallel requires proportionally more RAM per hash. Yescrypt has been adopted as the default password hashing scheme in several major Linux distributions, including Fedora Linux, Debian, Ubuntu, and Arch Linux. On systems that use it, a yescrypt hash is recognizable in the /etc/shadow file by its distinctive $y$ prefix, distinguishing it from hashes produced by SHA-512 or other legacy schemes still supported for compatibility.