However irrespective of the time at which the nodes

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However, irrespective of the time at which the nodes where inducted, A and B should be able to establish SAs. Thus key distribution schemes for MANETs should R1 cater to large network sizes ( N ); R2 facilitate ad hoc establishment of security associations (without a mediator); and R3 support asynchronous induction of devices into the network. 2.2. Schemes Based on Asymmetric Cryptography Scalable key distribution schemes based on asymmetric cryptographic primitives, which meet all three requirements (R1 to R3), can be broadly classified into certificate based (CB) and identity based (IB) schemes. Copyright © 2010. World Scientific Publishing Company. All rights reserved. May not be reproduced in any form without permission from the publisher, except fair uses permitted under U.S. or applicable copyright law. EBSCO Publishing : eBook Collection (EBSCOhost) - printed on 2/16/2016 3:46 AM via CGC-GROUP OF COLLEGES (GHARUAN) AN: 340572 ; Beyah, Raheem, Corbett, Cherita, McNair, Janise.; Security in Ad Hoc and Sensor Networks Account: ns224671
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34 M. Ramkumar 2.2.1. Certificate Based Schemes In the more conventional certificate based (CB) schemes, every node is associated with a unique ID, a public key, and a private key. Depending on the nature of the MANET, the unique ID could take various forms like MAC address (of the WiFi card), IP address, a telephone number, or SIM card ID. A node with ID A chooses a random private key R A and then computes the public key U A . The private key R A is a secret privy only to the node A . While the public key U A is made public, and can be computed from the private key, it should not be possible for any one to compute the private key R A from the public key U A . However, as the public key provides no information about the identity of the node, a certificate authority (CA) or the key distribution center (KDC) provides a binding between the public key U A and the ID A by issuing a public key certificate . More common CB schemes employ asymmetric cryptographic schemes like RSA, El Gamal or elliptic curve cryptographic (ECC) schemes in con- junction with a CA. Using its key pair, a node A can sign a message by appending a digital signature, which can be verified by any node which has access to the certified public key of A . For authenticated establishment of a shared secret K AB between A and B , both of them exchange their public key certificates. After verifying the public key of B , A can send a secret K A , encrypted using the public key of B . Similarly, B can send a secret K B encrypted using the public key of A . The common secret K AB can be then be computed as K AB = K A K B . 2.2.2. Identity (ID) Based Schemes In identity based (IB) schemes the public key of A is simply the ID A . Thus no certificates are necessary to bind the public keys of A to its ID. In IB schemes the KDC chooses some master secrets. Using the master secrets the KDC can compute private keys corresponding to any public key (ID).
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  • Spring '12
  • Kushal Kanwar
  • Public key infrastructure, ........., Public-key cryptography, Pretty Good Privacy

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