Crate mcaptcha_browser[−][src]

mCaptcha is a proof of work based Denaial-of-Service attack protection system. This is is a WASM library that you can embed in your frontend code to protect your service.

A commercial managed solution is in the works but I’d much rather prefer folks host their own instances as it will make the more decentralized and free.

Workflow:

mCaptcha workflow in the frontend is simple.

  1. Call service to get a proof of work(PoW) configuration
  2. Call into mCaptcha to get PoW
  3. Send PoW to mCaptcha service
  4. If proof is valid, the service will return a token to the client
  5. Submit token to your backend along with your app data(if any)
  6. In backend, validate client’s token with mCaptcha service

Example:

generate proof-of-work

fn main() {
   use mcaptcha_browser::*;
   use pow_sha256::*;


   // salt using which PoW should be computed
   const SALT: &str = "yrandomsaltisnotlongenoug";
   // one-time phrase over which PoW should be computed
   const PHRASE: &str = "ironmansucks";
   // and the difficulty factor
   const DIFFICULTY: u32 = 1000;

   // currently gen_pow() returns a JSON formated string to better communicate
   // with JavaScript. See [PoW<T>][pow_sha256::PoW] for schema
   let serialised_work = gen_pow(SALT.into(), PHRASE.into(), DIFFICULTY);


   let work: Work = serde_json::from_str(&serialised_work).unwrap();

   let work = PoWBuilder::default()
       .result(work.result)
       .nonce(work.nonce)
       .build()
       .unwrap();

   let config = ConfigBuilder::default().salt(SALT.into()).build().unwrap();
   assert!(config.is_valid_proof(&work, &PHRASE.to_string()));
   assert!(config.is_sufficient_difficulty(&work, DIFFICULTY));
}

Structs

Work

Functions

__wasm_bindgen_generated_gen_pow

generate proof-of-work

gen_pow

generate proof-of-work