bcrypt Variant
bcrypt variants are schemes that adjust the cost factor, salt length, or hash output on top of standard bcrypt (Blowfish-based password hashing).
Purpose
Adapts bcrypt's security model to platform limits or hardens it — e.g. fixing bcrypt's 72-byte password truncation issue.
Mechanism
Standard bcrypt uses EksBlowfishSetup from Blowfish to key 18 rounds from the password and salt, iterates 2^cost times, and outputs 192 bits. Variants may pre-hash with SHA-512 to bypass the 72-byte limit or adjust the round count.
Use cases
- Password hashing and storage
- bcrypt-compatible improvements
- Cost factor tuning