# US 8,572,120 B2 · Method and device for controlling access to a shared document in station-to-station communication network > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,572,120 B2 - Document ID: US8572120B2 - Status: Granted - Kind: B2 - Application number: 11/018,392 - Filed: 2004-12-22 - Published: 2005-06-23 - Granted: 2013-10-29 - Earliest claimed: 2003-12-22 - Assignees: Canon Kabushiki Kaisha - Applicants: Eric Nassor; Frédéric Maze - Inventors: Eric Nassor; Frédéric Maze - Web page: https://patentgrep.com/patent/US8572120B2 ## CPC - H04L 63/08: {for authentication of entities (cryptographic mechanisms or cryptographic arrangements for entity authentication H04L9/32)} - H04L 63/123: {received data contents, e.g. message integrity} - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract The access method comprises the following steps: i) receiving a request coming from a user for accessing at least one digital document, said request comprising an identifier (303) designating the digital document and an identifier (304) designating said user; ii) searching locally for at least one collection (C1) containing the identifier (303) of the document and the identifier (304) of the user, each collection (C1, C2) being stored locally in response to a positive verification with regard to at least one condition agreeing to supply the document according to at least one access right linked to the collection; and iii) in the case of a positive search, supplying said corresponding document (303) to said user (304) thus designated. ## Claims ### Claim 1 A method of accessing a digital document in a peer-to-peer communication network, in which peers are capable of exchanging data, said method being implemented in a first peer of the communication network and comprising the following steps: i) receiving, from a second peer of the communication network, at least one digital document and a collection comprising at least one document identifier designating the at least one digital document and at least one user identifier designating a user having a right to access any document identified in this collection, wherein the at least one digital document represents data items which can be shared with another peer via a peer-to-peer communication, and wherein the collection represents meta-data which controls access to the at least one digital document for sharing with another peer; i1) verifying at least one condition agreeing to supply from the first peer any document identified in the collection to any user identified in the collection; ii) storing locally the at least one digital document and the collection, received from the second peer, in response to a positive outcome of the step, of verifying the at least one condition; iii) receiving a request coming from another peer on behalf of a specific user for accessing at least one digital document, the request comprising an identifier designating the document and an identifier designating the specific user; iv) searching locally for at least one locally-stored collection containing the identifier of the document and the identifier of the specific user as a user having a right to access any document identified in the at least one locally-stored collection; v) in the case of a positive search, supplying the document to the peer; and vi) in the case of a negative search, supplying the document to the peer if at least a further condition is verified. ### Claim 2 (depends on 1) A method according to claim 1, further comprising, in the case of a negative search in step iv), obtaining at least one collection containing the identifier of the document and the identifier of the specific user and locally storing the collection thus obtained, if the further condition is validated. ### Claim 3 (depends on 1, 2) A method according to claim 1 or claim 2, further comprising a step iii1) of verifying the identity of the sender of the access request, established by means of a chosen authentication function. ### Claim 4 (depends on 1) A method according to claim 1, wherein the request for accessing a digital document also comprises the identifier of a collection containing the identifier of the requested digital document. ### Claim 5 (depends on 1, 2) A method according to claim 1 or 2, wherein step i) is preceded by the following steps, performed in the following order, in the second peer: a) creating a collection by designating at least one digital document to be shared by an identifier and assigning to an addressee user a right to access the document by associating the identifier of the document with an identifier of the addressee user; b) forming a notification containing the collection thus created; and c) sending the notification thus formed to at least one addressee user. ### Claim 6 (depends on 5) A method according to claim 5, wherein the receipt of a notification in the first peer is followed by a step of authenticating each collection thus received according to a chosen authentication function. ### Claim 7 (depends on 6) A method according to claim 6, wherein, in the case of negative authentication of the collection, provision is made to destroy the collection thus received. ### Claim 8 (depends on 6) A method according to claim 6, wherein, in the case of positive authentication of the collection, provision is made to verify the at least one condition agreeing to supply the document of the collection and locally store the collection thus received. ### Claim 9 (depends on 8) A method according to claim 8, wherein, in the case of a negative verification of the at least one condition agreeing to supply the document of the collection, the method further comprises the following steps for each document in the collection: 1) searching locally for the presence of another collection containing at least the identifier of a document belonging to the collection thus received; 2) in the presence of another collection containing at least the identifier of a document belonging to the collection thus received, verifying the at least one condition agreeing to supply the document of the other collection; and 3) in the case of a positive verification of the at least one condition agreeing to supply the document of the other collection, locally storing the collection thus received. ### Claim 10 (depends on 9) A method according to claim 9, wherein, in the case of failure of step 3), the method further comprises viewing the collection and, in the case of manual validation of the collection, locally storing the collection. ### Claim 11 (depends on 1, 2) A method according to claim 1 or 2, wherein the digital document belongs to the group formed by fixed images or photographs, video sequences, computer files for office automation application or the like. ### Claim 12 (depends on 1, 2) A method according to claim 1 or 2, wherein the at least one condition agreeing to supply the document of the collection relates to whether the author of the collection belongs to a chosen list of users referred to as friends, the condition being valid when the author of the collection belongs to such a list of friends. ### Claim 13 (depends on 1) A method according to claim 1, wherein the collection to be stored also comprises an author identifier designating the author of the collection and wherein said step of verifying the at least one condition further comprises: verifying a first condition according to which the author identifier belongs to a chosen local list of user identifiers referred to as “friends”; in a case where the first condition is not valid, verifying a second condition according to which, for each document identifier of the collection, there exists at least one local collection stored on the first peer that contains the document identifier of the document, and the author identifier in the collection to be stored as either the author identifier or a user identifier of the at least one local collection; and in a case where the second condition is not valid, verifying a third condition according to which the identifier of the first peer is one of the user identifiers of the at least one local collection. ### Claim 14 (depends on 13) A method according to claim 13, wherein said step of verifying the first condition further comprises the step of comparing the author identifier with locally stored identifiers. ### Claim 15 A device for accessing a digital document in a peer-to-peer communication network, in which peers are capable of exchanging data, said device being incorporated in a first peer of the communication network and comprising: means for receiving, from a second peer of the communication network, at least one digital document and a collection comprising at least one document identifier designating a digital document and at least one user identifier designating a user having a right to access any document identified in this collection, wherein the at least one digital document represents data items which can be shared with another peer via a peer-to-peer communication, and wherein the collection represents meta-data which controls access to the at least one digital document for sharing with another peer; means for verifying at least one condition agreeing to supply from the first peer any document identified in the collection to any user identified in the collection; means for storing locally the at least one digital document and the collection, received from the second peer, in response to a positive outcome of verifying the at least one condition; means for receiving a request coming from another peer on behalf of a specific user for accessing at least one digital document, the request comprising an identifier designating the document and an identifier designating the specific user; means for searching locally for at least one locally-stored collection containing the identifier of the document and the identifier of the specific user as a user having a right to access any document identified in the at least one locally-stored collection; means for supplying, in the case of a positive search, the document to the peer; and means for supplying, in the case of a negative search, the document to the peer if at least a further condition is verified. ### Claim 16 (depends on 15) A device according to claim 15, wherein the digital document belongs to the group formed by fixed images or photographs, video sequences, computer files for office automation application or the like. ### Claim 17 (depends on 15, 16) A system for accessing a digital document in a peer-to-peer communication network, comprising an access device incorporating the device according to any one of claims 15 to 16. ### Claim 18 (depends on 1, 2) A non-transitory computer-readable storage medium storing an executable computer program for causing a computer to perform a processing method according to any one of claims 1 to 2.