0
$\begingroup$

Suppose I have two messages $m_1$ and $m_2$ as well as $c_1$ and $n$. It's standard RSA so $c_1 = m_1^e \ mod \ n$, $c_2 = m_2^e \ mod \ n$. Further assume the only information we have about e is that it is smaller than $2^{2048}$. Is there a way to find it? (According to this it is not)

$\endgroup$
2
  • $\begingroup$ Is there some reason why you think the answers to that duplicate you linked to would be wrong? $\endgroup$ Commented Apr 22, 2019 at 21:11
  • $\begingroup$ no particular one, I just couldn't wrap my head around it for some reason. $\endgroup$
    – S. L.
    Commented Apr 23, 2019 at 9:34

1 Answer 1

2
$\begingroup$

No, it is not possible.

If it were, then RSA would be insecure; the same way to recover $e$ from $m_1, m_1^e \bmod n$ would be able to recover the private key $d$ from $c_1, c_1^d \bmod n$ (as that's the same problem, only using different symbols).

$\endgroup$
1
  • $\begingroup$ :facepalm: of course. $\endgroup$
    – S. L.
    Commented Apr 22, 2019 at 19:25

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.