PyPIn

PyPIn is a hypothetical open-source Python library designed to assist developers in implementing and managing Personal Identification Numbers (PINs) within applications. The project aims to provide a safe, flexible toolkit for PIN generation, validation, and secure storage, while remaining independent of web frameworks or database backends.

Core components include a PIN generator that enforces length, character set, and anti-pattern rules; a validator that checks PINs against policy; and a secure hash and verification layer to protect stored PINs. The library supports pluggable backends for hashing and for storage adapters, enabling integration with common authentication workflows.

Security and policy features are a central focus. PyPIn emphasizes resistance to common PIN weaknesses such as short length and sequential digits, and offers timing-safe verification, optional rate limiting hooks, and peppering options. It also provides guidance on secure storage practices and integration with existing security controls.

Design and implementation take a modular approach. The codebase is lightweight with clearly defined interfaces between generation, validation, and storage components. It is designed for Python 3.7 and newer and aims to minimize external dependencies while remaining extensible for custom workflows.

Usage typically involves configuring a PIN policy (including length, allowed character sets, and forbidden patterns), generating or accepting a PIN, hashing it for storage, and verifying user input against the same policy during authentication.

History and reception notes describe PyPIn as a concept and educational project maintained by a community of contributors. It is commonly described as an open-source library intended to illustrate best practices in PIN handling rather than as a widely deployed production solution.

See also: Personal Identification Number, PIN security, password hashing algorithms such as Argon2 and bcrypt, two-factor authentication.