It's not a 'startup'. It's a project by the founders of VK, and they surely have deep pockets.
Re:$300k for Cracking Telegram Encryption
by Sambdala on Tuesday November 04, 2014 @01:40PM
(#8558233)
Even ignoring that $300k isn't that much for most companies, there's insurance for big prize payouts where you'd pay the expected % time you'd have to pay out times the prize amount, plus a vig for the insurance provider.
For big prize payout contests, I'd get a lot more serious if they provided proof that the funds were waiting in escrow until end-date/winner.
But I'm probably unnecessarily suspicious of the depth of a startup's pockets...