Greetings from Tessellator Research team! We present a complete, trustless and permissionless bridge between Fastnet and Testnet networks.


All requested functionality is implemented:
- Lite-client smart contract with fully functional 'new_key_block' and 'check_block' message handling.

- Transaction-checker smart contract that handles 'check_transaction' and responds with 'transaction_checked' message.

- A 'test-cli' program that takes user's wallet seed phrase and either verifies transaction presence in Masterchain or submits a new key block to the Lite-client.


Find the latest updates and more on our GitHub - https://github.com/tessellator-research/ton_bridge_contest

potential issues:
1. lite-client only accepts key_blocks where next_validators is set
2. both JS and FunC code looks less readable and maintainable than in some of other submissions (such as a lot of magic numbers in FunC)
3. Tests fail, even node_modules tweak described in README didn't help. ERROR: TypeError: The first argument must be of type string or an instance of Buffer, ArrayBuffer, or Array or an Array-like Object. Received undefined
4. It is possible to make `check_transaction` message with such specific coins amount that gas will be exhausted during lite-client's `check_block`. In this case `transaction-checker` won't receive neither response nor bounce from lite-client, and `pending_checks` will store this pending query record forever and grow storage size over time.
5. in transaction checker queryId is a random 64 bit number, so collisions are possible (even worse with previous point I stated). I think query_id should just be stored as number and incremented

1. It's hard to read code.
2. Lite-client and tx-checker work only with ordinary cells. No support for exotic cells.
3. In lite-client you get all validators and use them to check signatures. You should get only 'main' validators.

Implemented basic functionality with a few security issues: no main_validators logic, not all keyblocks can be processed (requires `contains_next_validators?`). In tx-checker block is used as proof (ok). No exotic - thus expensive (and won't work for big blocks).

More info on issues: https://contest.com/docs/TrustlessBridgeChallengeAssessment