Access structures are used in the study of security systems where multiple parties need to work together to obtain a resource. Groups of parties that are granted access are called qualified. In
set theoretic terms they are referred to as qualified sets; in turn, the set of all such qualified sets is called the access structure of the system. Less formally it is a description of who needs to cooperate with whom in order to access the resource. In its original use in
cryptography
Cryptography, or cryptology (from grc, , translit=kryptós "hidden, secret"; and ''graphein'', "to write", or ''-logia'', "study", respectively), is the practice and study of techniques for secure communication in the presence of adver ...
, the resource was a secret
shared
Shared may refer to:
* Sharing
* Shared ancestry or Common descent
* Shared care
* Shared-cost service
* Shared decision-making in medicine
* Shared delusion (disambiguation), Shared delusion, various meanings
* Shared government
* Shared intellig ...
among the participants.
Only subgroups of participants contained in the access structure are able to join their shares to recompute the secret. More generally, the resource can also be a task that a group of people can complete together, such as creating a
digital signature, or decrypting an encrypted message.
It is reasonable to assume that access structures are
monotone
Monotone refers to a sound, for example music or speech, that has a single unvaried tone. See: monophony.
Monotone or monotonicity may also refer to:
In economics
*Monotone preferences, a property of a consumer's preference ordering.
*Monotonic ...
in the sense that, if a subset S is in the access structure, all sets that contain S as a subset should also form part of the access structure.
See also
*
Access control
*
Secret sharing
Secret sharing (also called secret splitting) refers to methods for distributing a secret among a group, in such a way that no individual holds any intelligible information about the secret, but when a sufficient number of individuals combine t ...
*
Threshold cryptosystem
References
Access control
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