I'm trying to do learn a bit about RSA by doing CTF's and now I am doing one problem probably more than 7 hours so I would really appreciate a hint here from an expert.
I have an encrypted message $c$, the modulus $n$ and the public exponent $e$ (variable names are by the definition of the wikipedia article). The exponent $e$ is of the same length (308 digits in base10) as the message $c$ and the modulus $n$.
The first thing I thought was that the exponent $e$ so large that no computer would be able to calculate $m^e$ if m is bigger than $1$. So I thought that the message $c$ must be the same as the non-encrypted message $m$. Converting $c$ to base16 and then to ASCII just gave me a bunch of non-sense.
After searching through the internet a lot I found a statement by a user that if the public exponent $e$ is very large it is likely that the private exponent is very small. So assuming the calculation of $m^e$ is possible I tried to decrypt the message with common small exponents $d (3,17)$ but this also did not work.
Since I am really stuck here, I would be very glad for a hint.