the difference here is that there's no "fake-world" contest. Tarsnap is asking for a real-world hack of their system. Telegram, on the other hand, is trying to

the difference here is that there's no "fake-world" contest. Tarsnap is asking for a real-world hack of their system. Telegram, on the other hand, is trying to prove that their algorithm is unbreakable. AES is pretty good too. As is noted in other comments, it's generally the system, not the algorithm, that gets broken.