If you know, you know; otherwise you might waste a lot of time.
This PHP code was provided when the above link is visited. PHP's == is notoriously know for type juggling. You can learn more about the vulnerability here.
The baseline is that, == operator in PHP converts strings which look like a number to a number before comparing. So,
sha(10932435112) gives 0e07766915004133176347055865026311692244, which in integer terms is 0*10^07766915004133176347055865026311692244. We know that == converts anything which looks like integer, so 0^anthing is zero. Now this value is getting compared to the \(hash variable which is the sha1(\)hash which we send). So we need to find a string whose sha1() produces a hash starting with 0e
I just googled "sha1 hash starting with 0e". I used this [link](https://github.com/spaze/hashes/blob/master/sha1.md), and took the first stringaaroZmOk
. Sending this data, we get the flag.[http://chall.csivit.com:30272/?hash=aaroZmOk