2
$\begingroup$

CCS '16

This image is taken from Algorithm 1 from "Σoφoς – Forward Secure Searchable Encryption, CCS '16".

On line 4 there seems to be a new variable, M, that is never defined throughout the rest of the paper. Should I attain a random byte[] and set that as the value of ST_0?

This is being implemented on a Java programme.

$\endgroup$
3
$\begingroup$

$\mathcal{M}$ is the domain of the inverse trapdoor permutation $\pi^{-1}$. For example, if $\pi^{-1}(m)= m^d \bmod N$ implemented using RSA, then $\mathcal{M}=Z^*_N$. The domain/range of $\pi$ and $\pi^{-1}$ are all $\mathcal{M}=Z^*_N$.

Generate a random big integer in $Z^*_N$ (roughly from range 1 to $N$) should be fine (there is a negligible probability of getting something not in $Z^*_N$, but since it is negligible we don't care).

| improve this answer | |
$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

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