In Fedora 35, a transition to the use of the yescrypt password hashing scheme is planned. This change has not yet been reviewed by the FESCo (Fedora Engineering Steering Committee), which is responsible for the technical aspects of Fedora distribution development. If approved, starting with Fedora 35, passwords for new users in /etc/shadow will be hashed using yescrypt by default. Support for old hashes created using the previously used sha512crypt algorithm will be maintained and available as an option. Notable distributions that have already transitioned to yescrypt include ALT Linux, Debian Testing, and Kali Linux.
Yescrypt extends the capabilities of traditional scrypt by supporting schemes with higher memory usage and reduces the effectiveness of attacks utilizing GPUs, FPGAs, and specialized chips. The security of Yescrypt is ensured through the use of well-established cryptographic primitives: SHA-256, HMAC, and PBKDF2.
Among the drawbacks of the sha512crypt algorithm used in Fedora is its efficiency only with a salt size exceeding 90 bits (at least 128 bits is recommended); vulnerability to DoS attacks through creating parasitic CPU load when hashing long passwords; vulnerability to attacks based on determining password size through passive timing analysis of hash processing; and operation without using a cryptographic key derivation function (KDF).
Source: opennet.ru
