BFT-algorithms are designed to solve the so-called task of the Byzantine generals, when one or more participants in the system may have hostile intentions, which should not interfere with its overall performance.
Thanks to the Catchain algorithm, the TON network will be able to successfully cope with its functions, while at least a third of the nodes remain honest, which corresponds to the theoretical limit in the task. The system will strive to validate each block at the time of its creation, as Tendermint in Cosmos and dBFT in NEO do.
Each new block will be created during the block generation round, when the validators must reach agreement for a limited time. Otherwise, the block is skipped.
Each validator has a clearly defined role in the voting process for the block: someone must create a block, someone - put it to a vote, and the rest - vote. Roles change with each round, which should ensure the correctness of the procedure.
Telegram intends to use no more than 100 validators in the main network and from 10 to 30 in secondary ones. As tests in 2018 showed, such a system is capable of releasing a block every 5 seconds, subject to all consensus building procedures.
In many ways, the Catchain algorithm is similar to the PoS variations used by Cosmos and Algorand. The differences are in specific details, for example, in the method of interaction of nodes with each other.
It was previously assumed that the TON blockchain would be launched before the end of October 2019, but legal measures taken by the US Securities and Exchange Commission (SEC) regarding the company prevented this. Telegram and SEC should meet in court on February 18-19.
