'''Attribute-based encryption''' is a generalisation of [[public-key encryption]] which enables fine grained access control of encrypted data using [[Authorization | authorisation policies]]. The [[secret key]] of a user and the ciphertext are dependent upon attributes (e.g. their email address, the country in which they live, or the kind of subscription they have). In such t is possible only if the set of attributes of the user key matches the attributes of the ciphertext.<ref>{{cite web |title=What is Attribute-Based Encryption |work=Cryptography Stack Exchange |url=https://crypto.stackexchange.com/a/17894 |date=2014 }}</ref>
A crucial security aspect of attribute-based encryption is collusion-resistance: An adversary that holds multiple keys should only be able to access data if at least one individual key grants access.
