I've been tasked with building up some security exercises (basic CTF training kind of stuff) for work. This should contain a bit of crypto, but my knowledge in this space has been limited to using the right tools, not trying to roll my own, etc, so coming up with an example of bad crypto, but believably real, has been tough.
Specifically one of the flags would be encrypted, say a simple sentence, in a way that would be crackable, allowing for recovery of the plaintext with a bit of know how and some burned cpu.
Could someone point me to an example like that?
Thanks for any input.