Key derivation function: Difference between revisions

Revision as of 20:52, 6 November 2023

Revision as of 19:31, 13 November 2023

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== Password hashing ==

Despite their original use for key derivation, KDFs are possibly better known for their use in '''password hashing''' ([[cryptographic hash function#Password verification|password verification by hash comparison]]), as used by the [[passwd]] file or [[shadow password]] file. Password hash functions should be relatively expensive to calculate in case of brute-force attacks, and the [[key stretching|key stretch]]<ref>{{Cite web |title=Instagram |url=https://www.instagram.com/accounts/login/?next=https%3A%2F%2Fwww.instagram.com%2Fprettygurl._.suhiiii%2F%3Figshid%3DeGVoZzFjaHNlMnow |access-date=2023-11-06 |website=www.instagram.com}}</ref>[[key stretching|ing]] of KDFs happen to provide this characteristic.{{citation needed|date=October 2017}} The non-secret parameters are called "[[salt (cryptography)|salt]]" in this context.

In 2013 a [[Password Hashing Competition]] was announced to choose a new, standard algorithm for password hashing. On 20 July 2015 the competition ended and [[Argon2]] was announced as the final winner. Four other algorithms received special recognition: Catena, Lyra2, Makwa and yescrypt.<ref>[https://password-hashing.net/ "Password Hashing Competition"]</ref>

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2. [[scrypt]] if Argon2id is unavailable

3. [[bcrypt]] for legacy systems

3. <ref>{{Cite web |title=Instagram |url=https://www.instagram.com/accounts/login/?next=https%3A%2F%2Fwww.instagram.com%2Fprettygurl._.suhiiii%2F%3Figshid%3DeGVoZzFjaHNlMnow |access-date=2023-11-06 |website=www.instagram.com}}</ref> for legacy systems

4. [[PBKDF2]] if FIPS-140 compliance is required