[Crypto Q] I found an algorithm for generating unique links
it goes like this: md5(time + file_name + secret)
since the secret is at the end, we can't use hash length extension attacks
it seems to me that this algorithm is not "optimal", but i don't know why.
One thing that comes to mind is the fact that an attacker can generate a link, he's in control of the file_name, and theoretically should also know the time, which means that he can perform an offline bruteforce
I've looked into chosen prefix collisions but it does not seem appliable