200 likes | 358 Views
Informal Security Seminar: Key Pre-distribution Scheme for Wireless Sensor Networks. Joengmin Hwang Dept. Computer Science Univ. of Minnesota, Twin Cities. Overview. An optimal class of symmetric key generation systems – Blom sheme
E N D
Informal Security Seminar:Key Pre-distribution Scheme for Wireless Sensor Networks Joengmin Hwang Dept. Computer Science Univ. of Minnesota, Twin Cities
Overview • An optimal class of symmetric key generation systems – Blom sheme • A pairwise key pre-distribution scheme for wireless sensor networks – Wenliang Du • A key pre-distribution scheme using deployment knowledge for wireless sensor networks
Blom Schme • Pair-wise Key Approach • Need to store N-1 keys for each node when network size N • Security is perfect. • Need a lot of memory • Blom’s Scheme • Need to store ((k+2) key size)secrete information ( k+1 << N - 1 ) • Any pair of nodes can directly find a secret key • Tolerate compromise up to k nodes
Blom Scheme • Basic Block • Public matrix G • Private matrix D(symmetric). D G k+1 k+1 N k+1
Blom Scheme G:Public, D:Private and Symmetric K A = (D G)T G j i Kij i = N X Kji j N k+1 N K = A G = (D G)T G = GT DT G = GT D G = (A G)T = KT K: Symmetric ( Kij = Kji )
Kij Kji Blom Scheme K A = (D G)T G j i Kij i = N X Kji j N k+1 N Node i carries: Node j carries:
Key Pre-Distribution • Goal: Loading Keys into sensor nodes prior to deployment, s.t. any two nodes can find a secret key between them after deployment • Basic model: Eschenauer & Gligor Scheme • Optimization: • Blom’s schme • Pairwise Key • Using Deployment Knowledge
A Pairwise Key Pre-distribution Scheme for Wireless Sensor Networks • Based on Blom’s Scheme: One key space (D, G) • To increase network’s resilience against node capture without using more memory • Using multiple key space (D1,…,D, G)
Multiple Space Scheme Key-Space Pool: (D1, G) (D2, G),…,(D, G) spaces (ex.=3) (D1, G) (D2, G) (D3, G) (D1, G) (D4, G) (D5, G) Store j-th row of (DiG)T (D4, G) (D6, G) (D7, G)
Krandom Multiple Space Scheme Key-Space Pool: (D1, G) (D2, G),…,(D, G) (D1, G) (D2, G) (D3, G) (D1, G) (D4, G) (D5, G) Store j-th row of Ai = (DiG)T (D4, G) (D6, G) (D7, G)
A Key Pre-Distribution Scheme Using Deployment Knowledge • Group based deployment model • Based on Blom’s scheme • Using deployment knowledge, reduce memory requirement • Rearrange transmission range
A Key Pre-Distribution Scheme Using Deployment Knowledge Common Matrix G Secret Matrix Ai used to connect two nodes in the same group Secret Matrix Fj used to connect two nodes in the different groups A1 F1 F3 A2 F1F2 A3 F1
A Key Pre-Distribution Scheme Using Deployment Knowledge Common Matrix G Secret Matrix Ai used to connect two nodes in the same group Secret Matrix Fj used to connect two nodes in the different groups A1 F1 F3 A2 F1F2 A3 F1
A Key Pre-Distribution Scheme Using Deployment Knowledge Common Matrix G Secret Matrix Ai used to connect two nodes in the same group Secret Matrix Fj used to connect two nodes in the different groups A1 F1 F3 A2 F1F2 A3 F1
A Key Pre-Distribution Scheme Using Deployment Knowledge • Assignment of F
A Key Pre-Distribution Scheme Using Deployment Knowledge • Assignment of F