For implementation in Fedora 35 is scheduled The input to use the passwords for passwords for passwords Yescrypt . The change is not yet considered by the FESCO Committee (Fedora Engineering Steering Committee), which is responsible for the technical part of the development of the Fedora distribution. In the case of approval, the change starting with Fedora 35 Passwords for new users in / etc / shadow will be exhausted by default using Yescrypt. Support for old hashes created on the basis of the previously used SHA512CRYPT algorithm will be saved and available in the form form. From the distributions of the already switched on Yescrypt, Alt Linux, Debian Testing and Kali Linux.
yescrypt extends the possibilities of classic scrypt Support for the use of schemes with extensive memory flow and reduces the effectiveness of attacks using GPU, FPGA and Specialized chips. Safety Yescrypt is ensured by applying already proven cryptographic primitives SHA-256, HMAC and PBKDF2.
The deficiencies used in the Fedora algorithm SHA512CRYPT marks efficiency only with the size of SALT exceeding 90 bits (at least 128 bits are recommended); exposure to DOS attacks through the creation of a parasitic load on the CPU when having long passwords; exposure to an attack to determine the size of the password based on a passive analysis of hash processing time; Work without the use of a cryptographic key forming function (KDF, KEY DERIVATION FUNCTION).