Yescrypt

yescrypt is a cryptographic key derivation function used for password hashing on Fedora Linux,¹ Debian,² Ubuntu,³ and Arch Linux.⁴ The function is more resistant to offline password-cracking attacks than SHA-512.⁵ It is based on scrypt.⁵

It was designed by Alexander Peslyak, also known as Solar Designer, to be highly resistant to hardware-accelerated brute-force attacks. It features enhanced memory-hardness and "strongly sequential" processing, which reduces the threat of large-scale cracking attempts using GPUs, FPGAs, and ASICs. Attacks that rely on parallelization are made more resource-intensive by yescrypt requiring a substantial amount of RAM to compute a single hash. These security benefits and its scalability have led to its adoption as the default password-hashing scheme for several major Linux distributions, where it is identifiable in the /etc/shadow file by the $y$ prefix.