US 12627465 B2 / May 12, 2026

Attribute based encryption with bounded collusion resistance

An attribute based encryption system includes a key generator configured to generate a cyclic group (G) having a prime order q; generate an attribute key matrix (M); generate a master public key (MPK) based, at least in part, on the group (G) and (M); generate a master secret key (MSK) based on a first vector s and a second vector t that represent an encryption policy; generate a user secret key based, at least in part, on the MSK and on a set of one or more user attributes; and send the user secret key to a user device, wherein a ciphertext message can be successfully decrypted if a vector y associated with attributes of the user associated with the user secret key is orthogonal to each row of a set of rows of M selected according to a set of authorization attributes used to encrypt the ciphertext message.