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.
Background
In its original use in
cryptography
Cryptography, or cryptology (from "hidden, secret"; and ''graphein'', "to write", or ''-logy, -logia'', "study", respectively), is the practice and study of techniques for secure communication in the presence of Adversary (cryptography), ...
, the resource was a secret
shared 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 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
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Access control
In physical security and information security, access control (AC) is the action of deciding whether a subject should be granted or denied access to an object (for example, a place or a resource). The act of ''accessing'' may mean consuming ...
*
Secret sharing
Secret sharing (also called secret splitting) refers to methods for distributing a secrecy, 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 c ...
*
Threshold cryptosystem A threshold cryptosystem, the basis for the field of threshold cryptography, is a cryptosystem that protects information by encrypting it and distributing it among a cluster of fault-tolerant computers. The message is encrypted using a public key, ...
References
Access control
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