US Patent 11804949 Subscriber revocation in a publish-subscribe network using attribute-based encryption

Techniques for subscriber revocation in a publish-subscribe network using attribute-based encryption (ABE) are disclosed, including: generating a tree data structure including leaf nodes representing subscribers, subtrees of the tree data structure representing subsets of subscribers having different likelihoods of ABE key revocation; generating ABE keys associated with edges in the tree data structure; assigning ABE keys to the leaf nodes, each leaf node being assigned a subset of the ABE keys associated with edges that form a path from a root node to the leaf node; based at least on a revocation record that indicates one or more revoked subscribers, determining a minimal subset of ABE keys that covers all non-revoked subscribers; and encrypting a payload using an encryption policy requiring at least one ABE key in the minimal subset of the ABE keys, to obtain a ciphertext that is not accessible to the one or more revoked subscribers.