PHP Intersity

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I work for a train operator company. Yesterday we've got an anonymous email which stated that there are some security problems with our tickets.

The attacker said that he forged a ticket by exploiting crypto. It's not my domain and I could not understand what's wrong.

I've bought a train ticket from Moscov to Novosibirsk. I've also made a debug endpoint where you can paste the ticket content (base64-encoded QR code contents) in order to check validity. There are also some debug prints there.

Is it possible to somehow forge a ticket with another departure date?

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