METHOD FOR OPERATING A NETWORK, A SYSTEM MANAGEMENT DEVICE, A NETWORK AND A COMPUTER PROGRAM THEREFOR

• US 20110197064A1
• Filed: 09/28/2009
• Published: 08/11/2011
• Est. Priority Date: 10/06/2008
• Status: Active Grant

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Erdmann, Bozena, Garcia Morchon, Oscar
• Granted Patent: US 8,539,235 B2
• Time in Patent Office: Days
• US Class Current: 713/168
• CPC Class Codes: H04L 2209/56 Financial cryptography, e.g. electronic payment or e-cash
• CPC Class Codes: H04L 2209/805 Lightweight hardware, e.g. radio-frequency identification [RFID] or sensor
• CPC Class Codes: H04L 2463/061 applying further key derivation, e.g. deriving traffic keys from a pair-wise master key cryptographic mechanisms or cryptographic arrangements for generation of secret information including derivation or calculation of cryptographic keys or passwords H04L9/0861
• CPC Class Codes: H04L 63/061 for key exchange, e.g. in peer-to-peer networks cryptographic mechanisms or cryptographic arrangements for key agreement H04L9/0838
• CPC Class Codes: H04L 63/0823 using certificates cryptographic mechanisms or cryptographic arrangements for entity authentication involving certificates H04L9/3263
• CPC Class Codes: H04L 9/083 involving central third party, e.g. key distribution center [KDC] or trusted third party [TTP]
• CPC Class Codes: H04L 9/0841 involving Diffie-Hellman or related key agreement protocols
• CPC Class Codes: H04L 9/3093 involving Lattices or polynomial equations, e.g. NTRU scheme
• CPC Class Codes: H04W 12/041 Key generation or derivation
• CPC Class Codes: H04W 12/0431 Key distribution or pre-distribution; Key agreement
• CPC Class Codes: H04W 84/10 Small scale networks; Flat hierarchical networks

Abstract

The present invention relates to a method for operating a network comprising communicating devices representing nodes of the network. More precisely, the invention relates to a method for operating a network (1), comprising a node (D1) and a system management device (3), the system management device comprising a root keying material being a set of alpha-secure functions having a degree of complexity of, and the node being provided with a node keying material share of degree of complexity α derived from the root keying material. The method comprises the following steps, upon receipt at the system management device of a request for an external user (4) to gain access to the node (D1): the system management device generates an external user keying material share of degree of complexity α from the root keying material and an access identifier, the system management device generates an access keying material of degree of complexity less than α, from the external user keying material share and an identifier of the node, the system management device provides the external user with the access keying material share and the access identifier, the external user derives a key from the access keying material share, and transmitting this key and the access certificate to the node, the node computes a key from the access identifier and the node keying material share, and the node compares the key transmitted by the external user and the key computed by the node, so as to authenticate the external user.

Claims

1. A method for operating a network (1), comprising a node (D1, N) and a system management device (3, SMD), the system management device comprising a root keying material being a set of alpha-secure functions having a degree of complexity of α

, and the node being provided with a node keying material share of degree of complexity derived from the root keying material, the method comprising the following steps, upon receipt at the system management device of a request (Rqst) for an external user (U) to gain access to the node (D1, N);

a) the system management device generating an external user keying material share of degree of complexity α

from the root keying material and an access identifier,

b) the system management device generating an access keying material of degree of complexity less than α

, from the external user keying material share and an identifier of the node,

c) the system management device providing the external user with the access keying material share and the access identifier,

d) the external user deriving a key from the access keying material share, and transmitting this key and the access certificate to the node,

e) the node computing a key from the access identifier and the node keying material share, and

f) the node comparing the key transmitted by the external user and the key computed by the node, so as to authenticate the external user.

2. The method of claim 1, wherein the access identifier is the result of a hash function performed on an access certificate based on the request received by the system management device, and the node being provided with the hash function, wherein step c) further comprises the system management device providing the external user with the access certificate, wherein step d) further comprises the external user the access certificate to the node, and the method further comprising:

g) the node verifying the access certificate by computing the hash function of the access certificate and comparing the result with the received access identifier.

3. The method of claim 2, wherein the request received by the system management device comprises at least one access attribute, and the access certificate depends on this attribute.

4. The method of claim 3, wherein the access attribute comprises at least one of:

a node identifier, a parameter defining a period of validity, a parameter defining a limited set of actions authorized for the external user.

5. The method of claim 1, wherein the root keying material is a bivariate polynomial of degree alpha.

6. The method of claim 5, wherein step a) comprises evaluating a bivariate root keying material share at a first point corresponding to the access identifier, to obtain a monovariate polynomial of degree alpha corresponding to the user keying material, and step b) comprises b1) pre-computing, at least partly, the monovariate polynomial at a second point corresponding to the node identifier to obtain a monovariate polynomial of decreased degree.

7. The method of claim 6 wherein step b1) comprises computing the monovariate polynomial for a computing a set of the highest degree coefficients at the second point.

8. The method as recited in claim 7, wherein α

−

1 highest degree coefficients are computed.

9. The method of claim 1, wherein the root keying material, and thus the access certificates, are protected by means of uncorrelation methods.

10. The method of claim 1 wherein the system allows the delegation of access rights from a first node that got a keying material share from the system management device to a third node, so that the third device can access a second node that got keying material from the system management device.

13. A network comprising a system management device according to claim 1.

14. A computer program, embedded in a computer tangible medium, for implementing a method according to claim 1.

11. A system management device comprising a root keying material being a set of alpha-secure functions having a degree of complexity of α

+1 in each variable, the system management device being included in a network also comprising a node, and the system management device comprising;

means for, upon receipt of a request for an external user to gain access to the node generating an external user keying material share of degree of complexity α

+1 from the root keying material and an access identifier,

means for generating an access keying material of degree of complexity less than α

+1, from the external user keying material share and an identifier of the node, and

the system management device providing the external user with the access keying material share and the access identifier.

12. The system management device of claim 11, further comprising:

means for delegating access rights from a first node in the network to an external user so that the user can access a second node in the network without requiring communication with the system management device, and

uncorrelation means to uncorrelate the keying material shares distributed to the nodes in the network so that an attacker cannot get any information from the keying material shares distributed to the nodes in the network but the nodes in the network can still verify the access and delegation certificates linked to the keying material shares distributed from the system management device.