altcha-skills

Comprehensive guide for building spam/bot protection solutions with the Altcha Rust library. Use this skill whenever the user wants to: implement ALTCHA proof-of-work (PoW) challenges in Rust to protect forms, APIs, or web applications from bots and spam; create cryptographic challenges using PBKDF2, SHA-256/384/512, scrypt, or Argon2id algorithms; solve ALTCHA PoW challenges on the client side; verify challenge solutions on the server side; set up deterministic mode with key signatures for fast-path verification; integrate ALTCHA Sentinel server signature verification; verify form field hashes for tamper detection; build challenge-response endpoints in Rust web frameworks (Axum, Actix-web, Rocket, etc.); configure challenge difficulty via cost, key prefix, and algorithm parameters; handle challenge expiration and HMAC-based payload signing; or work with any ALTCHA protocol feature in Rust. Make sure to use this skill whenever the user mentions altcha, proof-of-work captcha, bot protection, spam protection, P