Protocols for Secure Communication in Wireless Sensor Networks

6.6. Comparing Interleaved and Multipath Authentication 207
Algorithm 7 is-path-compromised(p)
Global values:
A: the set of authentication links (pairs of nodes)
B: the set of compromised nodes
Input:
p: a communication path
Output:
Return true if p is compromised, false otherwise
1: c[s] := WHITE for all s ∈ p ⊲ Initialize colors
2: for i in {1,...,len(p)} do
3: s := p[i]
4: if s ∈ B then
5: c[s] := RED ⊲ Compromised nodes are colored RED
6: else
7: if ∀ j < i.(p[ j],s) ∈ A ⇒ c[p[ j]] = RED then
8: c[s] := RED ⊲ RED, if all incident authentications from RED nodes
9: end if
10: end if
11: end for
12: return c[p[len(p)]] = RED ⊲ Target node RED?
compromised. With an increasing number of nodes being compromised, security
deteriorates at a different rate for each attack type. For a large number
of compromised nodes, the protection is highest against a concentrated attack
and lowest against a random spread attack. For low numbers, the scheme holds
up well against all attack types, even the partitioning attack. Of course, this
result confirms the assumption as this scheme was intended to provide good
protection against the partitioning attack.
6.6 Comparing Interleaved and Multipath Authentication
6.6.1 Multiple Physical vs. Virtual Paths
There is an immediate similarity between interleaved authentication and multiple
path communication. Interleaved authentication creates multiple authentication
paths on top of a physical communication path. In multi-path communication,
multiple communication paths are explicitly used to transfer a message
and associated authentication codes. Thus in both cases, multiple (disjoint)
paths are being used for transmitting authentication information. By introducing
redundancy, both schemes are able to tolerate a number of compromised
nodes.
While establishing disjoint paths in a multi-path scheme requires a trade-