saltrandom

Saltrandom is a term used in computer security to describe a random salt value applied to a password before hashing. The salt is designed to prevent offline attacks by ensuring that identical passwords yield different hash outputs, and to defeat precomputed tables that attempt to reverse hashes. It is a foundational component of modern password storage.

Generation and storage: Saltrandom values are typically produced by cryptographically secure random number generators and should be unique per password. They are stored alongside the resulting hash so that verification can recompute the hash with the same salt. Salts are not secret; their secrecy is unnecessary, but their unpredictability and length contribute to security.

Usage and formats: Many modern schemes incorporate or manage salts automatically. Typical guidance calls for at least 16 bytes (128 bits) of entropy for a salt. Salts are commonly encoded in hex or base64 and may appear as part of the stored hash string in formats used by bcrypt, Argon2, PBKDF2, or scrypt.

Security considerations: Salts mitigate rainbow table attacks but do not replace strong passwords or robust hashing algorithms. The recommended practice is to use unique salts per password with a slow, memory-hard function and a sufficiently large salt. Reusing salts across users weakens protection; proper salt handling should accompany password policies and secure storage.

History and terminology: The concept of salting passwords emerged to defeat precomputed attacks and has become standard across modern hash schemes. 'Saltrandom' as a term is descriptive and often superseded by the broader 'salt' concept in practice.

See also: Salt (cryptography); Password hashing; Rainbow table; Argon2; bcrypt; PBKDF2; Scrypt.