Cryptography Reference
In-Depth Information
eavesdropping, and black-hole attack. In addition, the attacker can also launch a route-
suppression attack by advertising higher energy levels than its compatriots and attract
all the data.
Along with active attacks, as discussed above, LEACH-like protocols are suscep-
tible to many passive attacks. Nevertheless, it has been observed that such protocols
are more robust against insider attacks than most other types of routing protocols. As
cluster heads in LEACH-like protocols are the intermediary nodes to the sink, which
change from time to time on a rotational basis, they are perceived to be more robust to
node-capture attacks.
7.4.1.4 Protocol Initialization
In this ID-based routing scheme, the time taken for messages to travel from cluster
heads to sink nodes and vice versa is denoted as
T
s
, and the time for messages to travel
from ordinary nodes to their respective cluster heads is
t
i
. The public key is the node's
ID concatenated with the
t
i
(ID +
t
i
). By adopting the ID-based scheme, any sensor
node that would want to authenticate itself to another node has to obtain its private key
from the concerned Private Key Generator (PKG) (Section 4.3). Because each private
key is valid only during the current time interval, sensor nodes have to obtain a denota-
tion of the new time interval to renew the private key at the beginning of a new round.
Upon node revocation, the sink needs to broadcast the compromised node IDs to the
sensor nodes, and each node stores the revoked IDs within a certain round.
Before deployment, the key-predistribution phase is performed in the set-up phase:
Set-up phase:
• Generate public parameters
PP
(
p
,
q
,
E
/
F
p
,
G
1
,
G
2
,
e
), as described in Section
7.4.1.1. In addition, let
P
G
1
.
• Let there be two cryptographic hash functions, such as
H
1
for the point-mapping
hash function, which maps strings to elements in
G
1
, and
H
2
, which maps arbi-
trary inputs to fixed-length outputs, as shown below:
*
*
H
:{0,1}
(7.2)
1
1
and
{0,1}
n
HG
:
for some
n
(7.3)
2
2
*
q
• Let
P
pub
=
P
as a network public key where
Î
(private key of the PKG)
• Preload each sensor node with the public system parameters (
p, q, E/F
p
, G
1
, G
2
,
e, H
1
, H
2
, P,
).
τ
Z
7.4.1.5 ID-Based Routing Protocol
In this scheme, each round has two phases: a set-up phase and a steady-state phase. Because
of the synchronization of time, sensor nodes know when each round starts and ends.
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