Patent ID: 8681983
Filing Date: 2014-03-25
Classification: H04L

Abstract:
1. A method for providing attribute-based encryption of a message using conjunctive normal form (CNF) expressions, the said CNF expression comprising at least one clause over a set of n attributes, the said method using a key generation engine, an encryption engine and a decryption engine, and comprising the steps of: a. generating by the key generation engine a random gεG, where G is a prime order group of order p where p is a primer number, four random values α,γ,β,rε b. generating by the encryption engine an encryption key PK=(g c. for an abovementioned CNF expression over a set of attributes, CNF expression comprising N clauses, generating by the encryption engine N random values t generating by the encryption engine a cryptogram hdr=(g n t ,hdr 1 , . . . ,hdr N ) consisting of at least 2N+1 group elements and generating a session key SK, wherein the said session key or parts thereof is used to derive a symmetric key which is used to encrypt the message, or to encrypt the message with the said session key; d. generating by the key generation engine a plurality of private decryption keys dk