5
$\begingroup$

In this paper, the definitions are simply as follows.

Multi-Level secret sharing: Higher level participants can help lower participants to get the secret.

Compartmented secret sharing: Each level participants has to get its own secret. (No help from higher level participants)

According to this paper

I found that Disjunctive Multi-Level secret sharing is identical to Multi-Level secret sharing and Conjunctive Multi-Level secret sharing is identical to Compartmented secret sharing.

Is above statement true?

My doubt is what is the difference between hierarchical secret sharing and multi-level secret sharing?

Is hierarchical secret sharing same as Disjunctive Multi-Level secret sharing?

If I add a restriction to the compartmented secret sharing that 'participants at level $i$ can recover its secret only if participants at level $i-1$ recovers their secret', then what we can call this type of secret sharing?

$\endgroup$
3
$\begingroup$

In a multilevel secret sharing scheme there is only one secret $S$ that all levels seek to find. In a compartemnted scheme we can have multiple secrets that correspond to each level that must be found before $S$ can be recovered. In a compartmented scheme a set of compartments must work together to recover the secret, where each compartment contains a number of participants. In a hierarchical scheme participants from different levels can work together to discover the secret, but they don't have to.

As far as I know hierarchical is interchangeable with multilevel. A disjunctive scheme is indeed simply a hierarchial scheme where participants from different levels can work together but can also find the secret by cooperating with participants on their own level. However a conjunctive scheme is what Tassa terms a hierarchial threshold scheme (see: http://www.openu.ac.il/personal_sites/tamirtassa/download/journals/htss.pdf).

To give an example of this type imagine we have a scenario where there is a safe at a bank that must be opened by employees, however they cannot do this without being in the presence of two senior employees or a manager. This type of scheme is not the same as a compartmental scheme as not all levels must cooperate together to find the secret.

Additionally I think Nojoumian and Stinson have done something similar to what you propose: http://isyou.info/jisis/vol5/no2/jisis-2015-vol5-no2-02.pdf

Hope this helps.

$\endgroup$

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.