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Security in mobile ad-hoc networks using soft encryption and trust-based

multi-path routing

Authors: Prayag Narula, Sanjay Kumar Dhurandher, Sudip Misra, and Isaac Woungang.Sources: Computer Communications, article in press.Reporter: Chun-Ta Li (李俊達 )

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Outline Motivation Proposed routing strategy Comments

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Motivation Message security using trust-based multi-path

routing in MANETs Multi-path routing (on-demand routing)

divide the message into different parts Soft encryption

eliminate the need of Key Distribution Center and key transfer

using the message itself for encryption Trustworthiness

trusted node is allowed to feature in more paths

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Proposed routing strategy Trust level (-1 to 4)

4 : complete trust 0 : initial trust -1: complete distrust

Multi-path routingneighboring nodes

track and listen

leave nodedestination

source

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Proposed routing strategy (cont.) On-demand routing protocol

S D

A B C

E F G

H I J

R_REQ

R_REP

The R_REP message is appended with the trust level of the successor node by the node

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Proposed routing strategy (cont.) Message encryption

A 4n-bits message is divided into four parts of n bits each (denote these parts by a, b, c and d)

a’ = a XOR c

b’ = b XOR d

c’ = c XOR b

d’ = d XOR a XOR b

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Proposed routing strategy (cont.) Message decryption

A 4n-bits message is divided into four parts of n bits each (denote these parts by a, b, c and d)

a = b’ XOR d’

b = a’ XOR b’ XOR c’ XOR d’

c = a’ XOR b’ XOR d’

d = a’ XOR c’ XOR d’

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Proposed routing strategy (cont.) Trust defined strategy

4 : those nodes can be given the right to read the full message

3 : those nodes can be sure of finding 2n possible messages of which one would be correct

2 : those nodes can be sure of finding 2n * 2n possible messages

1 : those nodes can be sure of finding 2n * 2n * 2n possible messages

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Proposed routing strategy (cont.) Algorithm to select secure routes

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Proposed routing strategy (cont.) Example (four parts)

S D

1 1 1

1 1

1 3

1

2

2

2

a’

a’ a’a’

a’

b’b’

b’

b’ b’c’

c’ c’

c’ c’

d’

d’

d’ d’d’

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Comments A node with normal trust level may easily read the

partial message and the property of confidentiality would not be achieved.

S D

1 1 1

1 1

1 3

1

2

2

2a’

a’

a’a’

a’

b’b’ b’

b’b’

c’

c’c’

c’

c’d’

d’d’

d’ d’

{a, c}

{a}

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Comments (cont.) A node with normal trust level may easily

read the full message and the property of confidentiality would not be achieved.

b’

c’

d’

b’ d’XOR

a XOR

a

XOR

c’

d’ c

c XOR c’ b

b XOR b’ d

b’ d’

d’c’

b’ c’

a’ {a, c}

a’ {d}

a’ Ø

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Comments (cont.) If a, b, c, and d are encrypted by means of the

following equations

a’ = a XOR b XOR c

b’ = a XOR b XOR d

c’ = a XOR c XOR d

d’ = b XOR c XOR d

b’ d’

d’c’

b’ c’

a’ {b}

a’ {c}

a’ {a}

b’ d’ {d}c’

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Comments (cont.) Fabrication attack Lack of mutual authentication between source

and destination node Payment system Nuglets (virtual currency)

S D

A B C

E F G

H I J

R_REQ

R_REP

Nuglets (SA)Nuglets (SB) Nuglets (SC)

Nuglets (SH)Nuglets (SI) Nuglets (SJ)

Nuglets (SE) Nuglets (SF) Nuglets (SG)