bcrypt hash validator

The bcrypt hash validator enables automated verification of passwords against bcrypt hashes in software development and security workflows. By analyzing the hash, it identifies the version (2a/2y/2b) and the cost factor, then uses these parameters to re-hash the supplied password for comparison. The result is a clear boolean indicating a match and a set of diagnostic fields.
Conceptually, the tool follows a four-step process: parse the hash to extract salt and rounds; perform a bcrypt hash of the candidate password with those values; compare the produced hash to the input hash using constant-time comparison; and report the details. This separation of concerns makes it suitable for unit tests and automation scripts.
Audience and value: developers integrating authentication verification into tests, QA engineers validating login flows, security teams auditing password handling, and incident responders analyzing compromised samples. Unique differentiators include explicit version and cost reporting, support for multiple bcrypt variants in one pass, and a deterministic, timing-safe comparison to prevent side-channel leakage. Core features include input validation, robust error reporting, and structured outputs ideal for CI pipelines and logging.
Use cases include validating password resets, verifying migration results when upgrading hashing schemes, auditing password strength impacts at a given cost, and cross-checking hashes obtained from external systems. The tool emphasizes correctness, reproducibility, and automation-friendly outputs rather than UI or presentation.