I’ve got another task for you involving my little language, Prop!
It consists of the following expressions (denoted
- Boolean constants, written
- Boolean variables, written as any alphabetical string.
- Implies, written
e -> e.
- Equivalence, written
e <-> e.
- Negation, written
- And, written
e && e.
- Or, written
e || e.
You can also parenthesize any expressions or subexpressions (so, you can write
(a || b) && c). Here’s another example program:
(a || b) && c && d && (!d || b) || (b -> c) && (d <-> a)
This time, I’ve determined that the attached program is satisfiable, but I want to know the actual values that make this program satisfiable. Can you find me a satisfying model, please? When you’ve found one, submit a GET request to our server. Any missing keys are considered false.
Here’s an example request:
This request would treat
cand the rest of the variables as
false. Thus, it’s only necessary to assign the true keys to the value true.
Continue reading [sCTF 2016] [CODE 130 – I Can’t Get No Satisfaction] Write Up