GROUP MEMBERSHIP BLOCK CHAIN

摘要

A system and method for achieving authorization in confidential group communications in terms of an ordered list of data blocks representing a tamper-resistant chronological account of group membership updates. This method permits ad-hoc and decentralized group definition, dynamic and decentralized membership updates, open sharing, tamper resistance, and tracking of membership history. There are many applications of these techniques. One such application is enabling end-to-end encryption of instant messaging, content sharing, and streamed media.

主权项

1. A method to enable confidential communication among users who are members of a group, the method comprising:
at a first device associated with a first user who is a member of the group:
generating a first data block for an ordered list of data blocks representing a chronological account of group member updates to the group, the first data block including a timestamp of creation of the first data block, identity information of the first user, information specifying addition of at least a second user to be a member to the group, and information pointing to a location of encrypted content to be shared among members of the group, the encrypted content having been encrypted with a symmetric key of the first user;generating a group key that includes a hash of the first data block;encrypting a key material portion of the group key using a multi-recipient encryption process that indicates at least the second user as a recipient;communicating the ordered list and the group key to a communication resource to which a device of the second user has access; andsending to the device of the second user the information pointing to the location of the encrypted content, and information pointing to the ordered list and the group key.