Hi! Can anyone show some examples of using oracles in smart contracts? Or maybe there's another way to create an unpredictable random?

In what regard would you use it?

I found a realization on medium of randomizer, but i don't know yet how to connect it to my lottery contract

wait for __callback method for some time?

Lottery contract🤔 we draw jurors randomly based on staking, maybe that method would work for you as well

How is your random made, if it's not a secret?)

It's not, two sec

It's a module, for now using Ethereum blockhash. It will be moved to a VDF when VDF are ready.

block.blockhash(block.number) ? and it's safe enough? we used block.timestamp and got hacked for some ether

The blockhash is not perfect, it can be sometimes "rerolled", but it cannot be fixed to a particular value. If you are a miner, you may sometimes waive some ETH to reroll the number and sometimes chose between two of them. But can never fix it to a particular value.

So can I use it in lottery? And can random on blockhash be hacked other way? Like look from another contract result of blockhash function and predict random value

No a large lottery creates a incentive for miners to withhold blocks to influence the outcome

If they have like 50% of the tickets and they mine a block which loses they will drop the block and have another chance of winning

Lottery is small and it's like a game, so for miners there's no interest I think