An Improved and Anonymous Three-factor Authentication Key Exchange Protocol for Wireless Sensor Networks

Master's Thesis 2017 68 Pages

Computer Science - IT-Security



I dedicate this research work and feeling of gratefulness to my parents, brothers, wife and especially my loving late mother whom love and unconditional support constantly enabled me to get through the thick and thin of life.

Muhammad Waseem


With the Name of Almighty Allah, the Most Merciful, the Most Sympathetic all praise is to ALLAH, the Lord of the worlds, and the Holiest Man Ever Born our Prophet Mohammad (PBUH) the messenger of Allah. First and main, I should admit my limitless gratitude to Allah, the Ever-Thankful, for His helps and bless. I am absolutely persuaded that this effort would have never turn into reality, without His control. I would also like to convey my gratitude to my research Supervisor Dr. Shehzad Ashraf Chaudhry Assistant Professor at Department of Computer-Science Software Engineering International Islamic University, Islamabad. The door to His office was at all times open when I go in difficulty or hard a query concerning my thesis. He always permitted this thesis to be my personal work, but guide me in the right direction every time he thinking I required it. I am very appreciative to my colleagues and friends specially Mr. Fraz Ahmed Baig who has been so kind along the manner of doing my thesis. Lastly, I should express my extremely reflective appreciation to my parents, brothers and wife for their unconditional support and nonstop encouragement during my study, researching and writing of thesis. This achievement would never achievable without them. Thank you.


The concepts of Internet of Things (IOT) show that everything in the global network is interconnected and accessible. In IOT environment Wireless Sensor Networks (WSNs) play a very important role because of its ubiquitous nature which use for wide range of applications like military surveillance, health care, environmental monitoring, agriculture etc. WSNs consisting of large numbers of sensor nodes which sensed the sensory information from the physical phenomena and forward the same to the cluster head or gateway node, sensor node having limited battery power and cannot be recharge after deployment. WSNs are resource constraints in terms of memory, energy, computational cost and communication speed. This thesis is focus to developed light weight user authentication and key agreement protocol to access the real time information from the IOT environment. Most recently Amin et al. find out various security limitations of the Farash et al. protocol and they extended the same protocol to improve its security weaknesses and claimed that the protocol is secure in all aspects. In this thesis we scrutinized the Amin et al. protocol which reveals that the protocol still having numerous security weaknesses such as user anonymity and user traceability attacks. In response to aforementioned security limitations we designed robust smartcard base threefactor user authentication and session key agreement scheme for WSNs environment. We analyzed the novel protocol formally and informally, formal security verification has done by using BAN-Logic which show that the scheme achieve mutual authentication and session key agreement among the participant entities. Furthermore, this protocol has also simulated in popular security tool ProVerif which simulation results show that the protocol is safe and withstand against all possible attacks including the above mentioned. The performance of this scheme is also compared with associated schemes the novel protocol can be applicable in real-life applications.


1 Introduction . . 2

1.1 One-Factor Authentication . . 3

1.2 Two-Factor Authentication . . 4

1.3 Three-Factor Authentication . . 4

1.4 Preliminaries . . 4

1.4.1 Cryptography . . 4

1.4.2 Cryptanalysis . . 5

1.4.3 Cryptology . . 5

1.4.4 Symmetric Encryption . . 6

1.4.5 Asymmetric Encryption . . 6

1.4.6 OneWay Hash Function . . 7

1.4.7 Biohashing . . 8

1.4.8 Adversarialmodel . . . 8

1.4.9 BIT Wise XOR Operation. . . 9

1.5 Thesis outline . . 10

2 Literature Review 11

2.1 Review of Amin et al. Scheme. . . 13

2.1.1 SystemSetup Phase . . .14

2.1.2 Sensor Node Registration Phase . . 14

2.1.3 User Registration Phase . . 14

2.1.4 Login Phase . .15

2.1.5 Authentication and the Session Key Agreement Phase . . 15

2.1.6 Post-Deployment Phase . . 17

2.1.7 Identity Update Phase . . 17

2.1.8 Password Change Phase . . 17

2.1.9 Smartcard Revocation Phase . . 18

2.2 Cryptanalysis and Security limitations of Amin et al. Scheme . . 19

2.2.1 Anonymity violation and traceability attack . . 19

2.3 ProblemStatement . . 21

2.4 Chapter Summary . . 21

3 Proposed Solution 22

3.1 SystemSetup Phase . . 22

3.2 Registration Phase of the Sensor Node . . 23

3.3 User Registration Phase . . 24

3.4 Login Phase . . 24

3.5 Authentication and Session Key Agreement Phase . . 25

3.6 Post Deployment Phase . . 28

3.7 Identity Update Phase . . 28

3.8 Password Change Phase . . 29

3.9 Smart-card Revocation Phase . . 29

3.10 Chapter Summary . . 30

4 Security Analysis . . 31

4.1 Formal Security Analysis . . 31

4.1.1 Security Analysis with BAN logic . . 32

4.1.2 Rules of BAN-Logic . . 33

4.1.3 BAN Logic Procedure for Protocol Analysis . . 34

4.1.4 ProVerif . . 38

4.2 Informal Security Analysis . . 43

4.2.1 User Anonymity . . 43

4.2.2 User Untraceability . . 44

4.2.3 Stolen smart-card attack . . 44

4.2.4 Replay Attack . . 44

4.2.5 Off-line password guessing attack . . 45

4.2.6 User-impersonation attack . . 45

4.2.7 Gateway node impersonation attack . . 46

4.2.8 Sensor node impersonation attack . . 46

4.2.9 Privileged-insider attack . . 46

4.2.10 Session key computation attack . . 47

4.2.11 Verification of the session key . . 47

4.2.12 Mutual Authentication . . 47

4.2.13 Man-in-Middle attack . . 47

4.2.14 Protection of unauthorized login . . 48

4.2.15 Provision of Post-deployment phase . . 48

4.3 Chapter Summary . . 48

5 Performance and Security comparison . . 50

5.1 Security features comparison . . 50

5.2 Computation Cost Analysis . . 52

5.3 Communication Cost Analysis . . 52

5.4 Storage Cost Analysis . . 53

5.5 Chapter Summary . . 54

6 Conclusion and Future Work . . 55

List of Figures

1.1 Symmetric Cryptography . . 6

1.2 Asymmetric Cryptography . . 7

1.3 XOR Logic Circuit . . 9

1.4 Architecture of Network Model for user authentication in WSNs . . 10

2.1 Sensor node registration phase in [1] scheme . . 18

2.2 User registration phase in [1] scheme . . 19

2.3 Login and authentication phase in [1] scheme . . 20

3.1 Sensor node registration phase of proposed scheme . . 23

3.2 User Registration Phase of Proposed Scheme . . 25

3.3 Login and Authentication Phase of Proposed Scheme . . 27

List of Tables

2.1 Notation Guide . . 13

4.1 Notations and Concepts in BAN-Logic . . 32

5.1 Security requirements table . . 51

5.2 Comparison of computation cost and running time . . 53

5.3 Communication Cost of Proposed and other Protocols . . 53

5.4 Storage Cost Analysis . . 54

Chapter 1 Introduction

In the recent past, Wireless Sensor Networks (WSNs) are ever-present and using in a wide range of applications domains, like healthcare, disaster management, environmental mentoring, domestic, surveillance [2] security and agriculture. WSNs are containing small nodes which having the capabilities to sense, communicate and compute. Though early sensor-nodes were resource limited with restricted capabilities, but with the advancement of sensor hardware technology and time made it possible to prolonged their battery life memory and processing power [3]. Practically, the majority reservations in WSN applications are concerned at the gateway or from the back-end of the appliance scheme. Though, in different purposes, real time information may not access from the gateway-node just, but also be admittance in ad-hoc manner from any sensor login node. User authentication is critical whereas accessing the real time information. Thus, we need a strong authentication schemes in order to resist unauthorized user from accessing real-time data. However, so far few schemes have been proposed which are well suitable for WSNs [4]. In the start it was thinking that the WSN consisting only homogenous network means identical sensor nodes in terms of power capability etc are used but latterly found heterogeneous Wireless Sensor Networks which makes from dissimilar sort of nodes with different capability, in which some of nodes are more powerful computationally than other nodes e.g. gateway nodes. In terms of IOT notation, the variety of WSNs is not simply adopting, that's why the communications is stimulated from main infrastructure based network in which node only communicate to the gateway node, to ad-hoc networks whereas node are also corresponded directly with another node[5]. WSNs are still becoming more frequent and organized by way of IOT, thus demonstrated novel opportunity but also challenge which is required to be tackling. An instance of such would be an isolated user who desires to admittance a specific sensor-node of the WSNs. So this type of user requires to be allowed and, if made completely, permitted to collect data from or send instructions to the sensor-node. Ever since the majority significant and different quality of WSNs is their resource-limited structural design (i.e., restricted communicational and computational power), a lightweight security clarification is necessary, so urging the protection plan to be more practical [6]. An example of such, if remote users want to access a particular node or real time data from the concerned node, such a user requires fist to authorized that positively allowed to access or collect information from the concerned end. While the most essential issues of the WSNs are resource constraint architecture (i.e. restricted communicational and computational capability), hence a lightweight defense solution is obligatory, therefore the influence of the security proposes to be extra sensible. In two-factor authentication protocol [1] user favor low entropy because of their tow-factor, password and smart-card. But in tow-factor authentication adversary execute the off-line password guessing threat in polynomial moment. Hence, two-factor authentications cannot afford enough safety because of offline password guessing assault. In addition three-factor authentications protocols were developed which hold up on password, smart-card and biometric (e.g. fingerprint, retina iris) have achieved reputations. So security within this authentication is very strong because biometric information cannot be guessed easily, biometric information also not forgotten easily. Huang et al. [7] proposed three-factor authentication frame work for the protection of password guessing attack of two factor authentication and upgraded the same to three-factor authentication and tackle the guessing of password attack. Three-factor authentication using biohashing operation, generating protect template of biometric.

1.1 One-Factor Authentication

One-factor authentication developed in 1981 by Lamport for the security of information, in one factor authentication used only secure password/PIN code. It is also called single factor authentication SFA user credentials/Id and password was not more secure. Other difficulty PIN code-based authentications are need understand the carefulness to generate and keep in mind strong passwords. It is also required security from internal and external threat. PIN code/Passwords have the main familiar form of one factor authentication with small cost.

1.2 Two-Factor Authentication

Two-factor authentication actually used two authentication factors in two steps verification system, this authentication is provides extra layer of protection and formulates its complex for adversary to enter a person's, online accounts and devices because password alone was not sufficient for strong security. Therefore, Two-factor authentication have been exercised to protect access to susceptible information and online organizations, ever more introducing this authentication to protect their user data from whose password has been stolen or hacked from database or otherwise.

1.3 Three-Factor Authentication

Two-factor authentication practice [1] which depends on PIN code and smart-card, users usually used low-entropy password which is uncomplicated so as a result the adversary carry out off-line password guessing risk which guess the password of user's in polynomial time. Thus, two-factor authentication scheme cannot give high level protections due to the risk of off-line password guess-sing attack. Therefore, three-factor authentication schemes were developed which is based on PIN code, smart-card and biometrics (finger-print, retina and iris) have so gained esteem. In these three-factor authentication scheme, user gets pleasure from superior safety than a two-factor method as (i) biometric information is not guessed easily (ii) biometric information is not forgotten.

1.4 Preliminaries

In this section the basic three-factor authentication architecture and background for symmetric encryption have been described:-

1.4.1 Cryptography

Cryptography is actually the conversion of legible and understandable information into a shape which is unable to understand in order to protect the data. Cryptography refers precisely the techniques for hiding the message contents, the word of cryptography has been derived from a Grecian word Kryptos which means secret and graphikos that means writing. So the following are some main terminology of cryptography [8].

Plain Text: The data that we require to hide from view is known as plaintext (P), it is the original data or text, it might be in a shape of characters, mathematical data, executable program, image, or any extra kind of data. The plain text for instance is the initial draft of messages in the dispatcher before encryption, otherwise it is a text by the side of the receiver after the decryption.

Cipher text: The information that will be sending out is described as cipher text (C), it is a word which refers to the "meaningless" string information, or indistinct text that nobody have to understand, excluding the receiver. It is the information that will be sent out accurately through network, several algorithms are used to change plain text into cipher text [9]. Cipher is actually the algorithms which use to change the plain text into cipher text, this technique is known as encryption or (encode), in other terms, it is a technique for exchanging readable and explicable information into "meaningless" information, and moreover it is represented as under:

[Formula is omitted from this preview.]

Where C is a cipher text, E(K) is an encoding algorithm by using K key and P is a plain text. The reverse of cipher process is known as decipher (decode). It is the mechanism which recovers the coded text, this scheme is known as decryption, in additional terms it is the system of exchanging "meaningless" information into legible information.

[Formula is omitted from this preview.]

1.4.2 Cryptanalysis

Cryptanalysis deals with the study of encryption and already encrypted information for the objective to find out the hidden messages. Cryptanalyst can attempt any or these entire assaults (i) attempt for breaking of single message (ii) attempt to identify arrangements in encoded messages, to find out the successive ones by using straightforward decryption algorithm (iii) attempt to catch general flaws in an encryption algorithm, lacking of unavoidably having captured any message.

1.4.3 Cryptology

Cryptology is the study of both cryptanalysis and cryptography.

1.4.4 Symmetric Encryption

Symmetric Encryption is that type of cryptosystem in which the similar key used for encoding and decoding. Key plays significant role in this encryption. The distribution of the key should be done before communication between entities [10]. This encryption procedure is also known as single key or conventional encryption. There are numerals advantages of this method. Performance is comparatively more than other. In this technique having two main features, encryption algorithm and key. The encryption algorithm change plain text to cipher text by using the secret key and encryption algorithm. In the process of decryption the same process of encryption are used but in reverse order with the similar key. A robust algorithm should be contingent on its key exclusively. The flaws of symmetric algorithms are in distribution of symmetric key among the sender and receiver [11].

[Figure is omitted from this preview.]

Figure 1.1: Symmetric Cryptography

1.4.5 Asymmetric Encryption

Diffie and Helman was discover innovative encryption formula in 1976 which is known as asymmetric encryption or public key encryption. Asymmetric encryption is dissimilar than symmetric encryption in security, because it does not share the secret key between the dispatcher and the recipient, this is the key difference between asymmetric and symmetric encryption. In this encryption process the sender have the public key of the recipient and the receiver has its own private key which is not possible to find via the public key, so there is no need to share the key. It is the responsibility of the receiver to established public and his private key, also the receiver transmit the public key to every senders by some channel. He wants even public channels to deliver his asymmetric key or public key can use whichever the secret key or public to encrypt/decrypt the information. Public key encryption might be used to employ the authentication and non-repudiation security performance, it can also use for digital signature and further purpose that never be execute with symmetric encryption. Asymmetric encryption is very complicated and slower in computation than symmetric encryption. So, asymmetric encryption deal plaintext like a collection of numbers which are operated in mathematics, whereas the plaintext in symmetric encryption deal as collection of characters and symbol, the encryption procedure may transpose these symbols, or may replace one symbol by another [12].

[Figure is omitted from this preview.]

Figure 1.2: Asymmetric Cryptography

1.4.6 One Way Hash Function

In the mechanism of this function H: {0, 1}* Yq*which takes a variable length of data M as an input and produced fixed size of code/cryptogram C=H(M), the fixed size output C lexis which is known as hash code. So a small change in M produced considerable change in C [10]. The main properties of hash function are as under:

- It is easy computationally to get C = H (M), when M is known.

- It is infeasible computationally to calculate M, when C = H(M) is known.

- It is complicated to get two inputs M and T like H (M) = H (T). Thus this state is called collision-resistance state.

Definition 1: A hash function be an identical fellowships F=Cn of tracks of range polynomial into n, taking input of range n and produce output of range m < n. So this function family unit be a hash function because the input is separated into two parts, x plus k, so as to n is polynomial in:

[Formula is omitted from this preview.] [13]

1.4.7 Biohashing

The conception of Bio-Hashing is actually system of cancellable/disposable biometrics procedure. In this method, a Biometric features are integrated with user specific random numbers to deals the performance and security of the biometric system. In BioHashing method, the fingerprint data of user are result to store in extremely interrelated bit strings. Additionally in this technique the user particular code cannot be obtained by the adversary[14]. Thus this bio-hashing feature would secure our scheme beside any biometric improbable. Thus the illegal users can simply recognized by this mechanism. This tactic delivers the revocable characteristics in the biometric. Thus the chances of disclose of the real biometric pattern are abolished. Therefore, BioHashing has important beneficial advantages more than exclusively biometrics mistake rate point as well as clear division of the authentic and fraudulent people. The anticipated Biohashing methodology utilized non-invertibility procedure for enhanced safety along with performance [15].

1.4.8 Adversarial model

In this thesis common adversarial model contain all possible assumptions of the adversary as mentioned in [16]. According to the potential of the adversary A all possible assumption made by the adversary described as following:

1. A have complete control over the public channel, so A is capable to interrupt, modify, reply, takeout or can also send a fresh fabricated message.

2. A can also extract the smartcard information by power analysis or leak the same.

3. A can be external stranger or malicious insider user of the same system.

4. The insider known the ID of the register users and server because these are public.

5. Servers are usually understood to be safe but A cannot negotiate any server of the entire system (i.e. Secret key is not accessible to adversary).

1.4.9 BIT Wise XOR Operation

A simple XOR cipher is use in cryptography which is a form of preservative cipher, an encoding technique that functions according to the given standard.

[Formula is omitted from this preview.]

From the above principles show that result is true either one of the input is true, but not both. The result is false when both the inputs are true or if both the inputs are false. Simply it examine that the result is 1 if the inputs are dissimilar, otherwise 0 if the input are the similar. It is a main plus point of XOR that easy to employ, besides the XOR process is inexpensive computationally. In simple XOR operation in which the same key is use for XOR process on the total data this cipher is use for secure information in those cases wherever specific security is is needed. When keys are random and are at smallest along with the message, then XOR encoding is greatly secure than as the key replication in a message. While the key stream is produced through the random-number generator, then outcome be stream cipher by using really random key with the key that is really random, the outcome is one tim-pade which are strong even in idea.

[Figures are omitted from this preview.]

Figure 1.3: XOR Logic Circuit

Figure 1.4: Architecture of Network Model for user authentication in WSN

1.5 Thesis outline

Further arrangement of thesis are as under:

- Chapter 2, We discussed the literature study of previous papers, review of [1],detailed examination as well cryptanalysis of Amin et al.'s. In the last of chapter 2 we have been presented the problem statement of our research.

- Chapter 3, We presented the proposed solution which consisting of total nine phases.

- Chapter 4, We discussed the safety analysis of our scheme, we asses the same protocol formally with BAN logic and ProVerif as well informally analysis beside all possible attacks.

- Chapter 5, We write down the performance analysis of the improved protocol.

- Finally, we provided conclusion and future work in Chapter 6.

Chapter 2 Literature Review

Watro et al.[17] formed a user authentication protocol in 2004, with the name of Tiny-PK using Diffie-Hellman and RSA algorithm but the Tiny-PK scheme vulnerable to masquerade attack (the session key was encrypted by intruders alongwith new parameters and transmit encrypted data to the end user) but this protocol cannot capable to opposes man-in-the middle attack. Wong et al.[18] lunched forceful user authentication protocol in 2006 for WSNs using the hash function, this scheme permitted legitimate user to each sensor node at the network but Wong et al.[18] protocol is vulnerable to forgery and replay attack. Later on in 2007 Tseng et al.[6] improve Wong et al.[18] scheme and proposed improve user authentication scheme and enhanced the security flaws of Wong et al.'s scheme Tseng et al.'s[6] having four man phases, Registration , Login, Authentication and Password Change Phase but the Tseng et al.'s having some security flaws with different malicious attack. He et al.[19], in 2010 stated the weaknesses of M.L.Das's[20], protocol which was suffered from impersonation attack, insider attack and their password cannot change by the user. He et al. then enhanced the existing scheme with two factor authentication and reveal the weaknesses of Das's protocol. He et al. scheme is vulnerable to leakage of information attack, nonpreservation of user-anonymity, the session key cannot be recognized between the sensor node and user also this scheme has lack of mutual authentication stuck between the sensor-node and the user. Fan et al.[9] suggested a schemes which was uncomplicated user authentication protocol, which withstand denial of services (DoS) also resist user authentication protocol, this scheme established the session key stuck between the user and cluster node (header node) in WSNs. Vaidya et al.[21], stated that M.L.Das's[20] protocol and Khan-Alghatbar's[22] schemes having some security fault and vulnerable to different attacks, consisting of stolen smart-card attack, to overcome these security flaws of both protocols proposed tow-factor 11 authentication schemes which is portent smart card theft attack and other familiar kinds of vulnerabilities. In current era bio-metric user authentication also focus some research concentration. Yuan et al.[23], suggested a biometric authentication of user for WSN using the idea of M.L.Das's schemes. In this scheme GWN node cannot accept any acknowledgment in their scheme, furthermore, the sensor node and getaway node cannot known the message if attacker block it from accomplishment the node. The same scheme is also not flexible against node negotiation attack, but support freely changing of password on local based containing with the gateway node in the network as matched with other scheme. Xu et al.[24] and Song proposed a user authentication protocol which based on RSA and Diffie-Hellman to get the mutual authentication property. But the drawback of [24] schemes are overhead of memory because these protocols store all the public key of a node as well the user. To overcome the drawbacks of these protocols in 2011 Yeh et al.[25] proposed another ECC based asymmetric cryptographic protocol for WSNs. Kumar-Lee[26], pointed out some flaws of He et al.[19] scheme does not proved session key institution and mutual authentication connecting sensor node plus user. Kumar-Lee also stated that the He et al.[19] protocol have lack of user anonymity and information leakage attack. They also found absence of session key and mutual authentication in Khan-Algathber's scheme [22]. Ashok Kumar Das et al.[27], in 2012 proposed a hierarchical WSN user authentication protocol based on dynamic password, in this scheme the real time data can be right of entry from the nodes, because the real-time information are not only access through bas-station, so access are given to the outside user (parties) only to those who allowed to get information when they required. Hence authentication performs a very important role for the same purposes. This scheme also change password dynamically without base-station getaway node help as well support dynamic node addition. Turkanovic and Holbl[28], assert Das et al.[27] protocol is imperfect proposing enhanced protocols Turkanovic and Holbl and Li et al[29] but these protocols also not withstand all possible vulnerabilities. Recently, in 2014 Turkanovic et al.[5], proposed a lightweight user authentication protocol which based on hash-function and using the concept of IOT, with heterogeneous ad-hoc WSN. The main objective of this protocol was anonymity and energy efficiency with low computation cost and high security. However, Farash et al.[30], and Ruul and Biswas[2] stated that this protocols are not suitable for the realistic application due to it security weaknesses. Moreover, Rulul and Biswas using smart-card proposed user authentication protocol which was multi getaway based. In recent time Farash et al.[30] developed an improve protocol which also examined that this protocol cannot withstand offline password guessing threat, stolen smart-card attack, user anonymity problem, session explicit transitory information attack and password guessing attack.

[Table is omitted from this preview.]

Recently Amin et al.'s[1] suggested a three-factor IoT based authentication scheme for the achievement of security loophole in Farash et al.[30] in which they also claimed the anonymity. But after the insight perusal we scrutinized that the Amin et al.'s[1] protocol is still having user anonymity and user traceability attack detail review and cryptanalysis of [1] are as under:

[Formula is omitted from this preview.]

2.1 Review of Amin et al. Scheme

This scheme[1] consisting of total nine phases: System Setup Phase, Sensor Node Registration, User Registration, Login, Authentication and Session Key Agreement, Post Deployment, Identity Update, Password Change and Smartcard Revocation Phase these all are narrated as under.

2.1.1 System Setup Phase

The System Administrator SA performed this mode off-line, which comprising the following steps:

Step 1: SA selects the identity

[Formula is not in the preview]

Step 2: A master key XGN chosen by SA this key only known GN and computes

[Formula is omitted from this preview]

XSN is the secret key of SN which is unique for each SN.

Step 3: A random number Rshrd, is selected by SA and shared between SN and GN. SA finally stored{IDSN,XSN,R shrd} in temper proof memory of SN.

2.1.2 Sensor Node Registration Phase

After the setup phase the SA deploy the sensor node SN and single GN on the target area to make sensor network this phase as shown in figure 2.1 steps of the same phase are describe below:

Step 1: A SN computes S1 and S2, S1 =IDSN

[Formula is omitted from this preview.]

then send S1 and S2 with timestamp Ts1 via an unreliable channel with fresh time stamp to GN.

Step 2: GN verify these parameters with timestamp:

[Formula is omitted from this preview.]

Step 3: The confirmation message send to SN by GN after successful completion of registration phase and Rshrd are deleted by SN from memory.

2.1.3 User Registration Phase

This phase is illustrated in figure 2.2.

Step 1: A user Ui chosen an identity IDui send it alongwith personal credential via an unreliable channel to SA, personal credential support in re-issuing of fresh smart-card for Ui whose smart-card are either damage or stolen.

Step 2:

[Formula is not in the preview]

Here BK() is the biometric extraction and key generation function, SA keep a table in which store IDui and personal information of each user.

Step 3: U i entered the smart-card in the card reader. Ui enters (IDui, PWui) and fingerprint fngui through sensor device to smart-card. Then the smart-card compute:

[Formula is omitted from this preview]

2.1.4 Login Phase

When a register user want to get the real-time information it need to login with GN to access information. Narrative of this phase are given in figure 2.3:

Step 1:

[Formula is not in the preview]

Step 2: If Ui are valid and legitimate then the smart-card calculates

[Formula is omitted from this preview]

Step 3

[Formula is omitted from this preview]

2.1.5 Authentication and the Session Key Agreement Phase

This phase presented the authentication process as well as session key agreement are executing among Ui, GN and SN. The narrative of this phase is illustrated in figure 2.3.

Step 1: A login message MSG1 received to GN from Ui then GN computes

[Formula is omitted from this preview]

Step 2:

[Formula is not in the preview]

Step 3:

[Formula is omitted from this preview]

Step 4:

[Formula is omitted from this preview]

Step 5:

[Formula is omitted from this preview]

Step 6: GN check the timestamps T4 which is current timestamp or not if it is false the GN terminate the session, otherwise it computes:

[Formula is omitted from this preview]

Step 7:

[Formula is omitted from this preview]

2.1.6 Post-Deployment Phase

The purposes of subject phase is deployment of sensor nodes to forming a Network. If one or more node may be damage so this damage node S k replaced with a new node Snew on the target field. SA select IDnew and Snew to complete and embed this in memory of Snew.

[Formula is not in the preview]

2.1.7 Identity Update Phase

The main focus of this phase is the security to updates the identity of the registered user this phase required help of GN the legitimacy of Ui verify in login phase GN and smart-card compute the following:-

Step 1:

[Formula is omitted from this preview]

Step 2:

[Formula is omitted from this preview]

Step 3:

[Formula is omitted from this preview]

2.1.8 Password Change Phase

For the security enhancement the registered user Ui want to modify his/her password with-out the assistance of SA and GN. This phase express as under:-

Step 1: U i insert his smart-card within the card-reader and process step 1 of the login phase and verify password, identity and fingerprints.

Step 2:

[Formula is omitted from this preview]

Step 3: Smart-card update the old information (eui, gui, fui) with new {enew ui , gnew ui , fnew ui } in smart-card memory the rest of parameter keep unchanged.

2.1.9 Smartcard Revocation Phase

When the registered user smart-card may be stolen or lost this protocol issue the new smart-card by performing the below steps.

Step 1:

[Formula is omitted from this preview]

Step 2: The Ui insert smart-card, input IDui, password PWui and input fingerprint with device and computes:

[Formula and table are omitted from this preview]

2.2 Cryptanalysis and Security limitations of Amin et al.'s Scheme

The Amin et al.'s [1] protocol based on three-factor authentication for the anonymity preservation and key exchange protocol for WSN. We examined that the R. Amin et al.'s protocol is suffering with some serious flaws.

2.2.1 Anonymity violation and traceability attack

In addition with conventional security, user privacy and anonymity has an enormously emergent and important factor to be considered. Lacking of anonymity and privacy the user private information may be access by adversary through just investigating the session information such private information can be distorted by the adversary. In the present time of persistent computing, user's private information which can be obtained by an attacker with examining the session specific information. In WSN Networks, the adversary becomes capable to get the moving history and location of participant user's. For the provision of anonymity an authentication scheme should be achieve after the accomplishment of these two major goals: (a) actual identity of user is never exposed to adversary (b) also the adversary not able to find out the different sessions whichever initiate by similar user. An authorized user U i can able to break the anonymity by performing the following.

[Figure is omitted from this preview]

Figure 2.3: Login and authentication phase in [1] scheme

In Amin et al.'s protocol, the SCTx is transmitted over the open channel so, when a legal users sends more than one login request with the same ID the adversary A can easily trace the initiator/user with SCTx and trace out the user of the system which is clear violation of anonymity. Thus this problem may also lead to user traceability. Whereas

[Formula is omitted from this preview]

2.3 Problem Statement

In recent past researchers developed many authentication protocols for user authentication and security vulnerabilities in WSN and IOT environment. Furthermore, these schemes [1,2,5,30] respectively are efficient to overcome some security problems related to user authentication and agreement of the session key in WSN, but still these previous schemes are vulnerable to many security attacks. Most recently Amin et al. [1] find out various security limitations of the Farash et al.[30] protocol and they extended the same protocol to improve its security weaknesses and claimed that the protocol is secure in all aspects. In this thesis we scrutinized the Amin et al. protocol which reveals that the protocol still having the following numerous security weaknesses:

- 1. Traceability attack.

- 2. User anonymity

2.4 Chapter Summary

In WSN major issue is authenticity of message via a communication channel between the two parties to establish the exchange of data in safe way. In the aforementioned literature many protocols of WSN authentication were discussed by different researcher like password/pin code base authentication, two factor authentication but these schemes still having some issues of security. A Biometric based authentication were designed for the solution of the same problems because biometric keys are hard to steal, allocate, distribute and share. Biometrics based authentications are hard to guessed, steel and also not breakdown easily. In this chapter we discussed some related schemes of different researchers with their importance and limitations. In the last section of this chapter we stated the problem statement of our thesis.

Chapter 3 Proposed Solution

In this chapter, we explain the novel enhanced protocol which based totally on the flaws of Amin et al.'s scheme. The addendum scheme is not just forceful against all identified attacks but in addition conserved the innovative merits of the protocol of Amin et al.'s. The main identified loopholes of [1] is highlighted in registration phase and login and authen-tication phase of our proposed protocol. The key flaws of Amin et al.'s protocol is violation of user anony-mity and user traceability attack. Our proposed scheme based on symmetric cryptography due to constraint resources of WSN, we use three factor authentication to improve the Amin et al.'s protocol. We used simple encryption/decryption with simple hash function, XOR operation and biometric extraction function BK() for biometric features extraction. The proposed anonymous scheme resist against all possible attack and problem that are examined in [1] complete security analysis are given in chapter 4 of the thesis. Previous scheme were also based on three factor authentication but with non provision of anonymity. Our scheme is principally consisting of three participant entities i.e. user, sensor node and gateway node and comprising of nine phases which have been discussed in this subsection below.

3.1 System Setup Phase

The System Setup phase is actually configure in offline mode by the by the System Administrator SA. Description of this phase are as under:-

Step 1: SA selects the identity IDSN of the sensor node of SN

[Formula is omitted from this preview]

Step 2:

[Formula is omitted from this preview]

Step 3: The System Administrator SA chose a random number R shrd between the GN and SN. Finally SA push {IDSN,XSN,R shrd} in the temper memory of SN in safe way. So we imagine that adversary A not extract {IDSN,XSN,Rshrd} for the SN memory even if compromise.

3.2 Registration Phase of the Sensor Node

After the system setup phase the SA deploy the sensor node SN with a single GN on the target region and make a sensor network. This phase is illustrated in figure 3.1. In registration of the Sensor node SN every sensor-node SN carry out the underneath step with GN.

Step 1:

[Formula is omitted from this preview]

Step 2:

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Step 3: After the registration phase the confirmation message send to SN by GN after successful completion of registration and R shrd are deleted by SN from memory.

[Formula is omitted from this preview]

3.1: Sensor node registration phase of proposed scheme

3.3 User Registration Phase

This phase is shown in figure 3.2 also their steps are describe below:

Step 1: The user Ui select an identity IDui and send this identity alongwith personal record via a reliable channel to SA, personal record assist in re-issuing of fresh smart-card for those Ui whose smart-card are lost, stolen or damage by some reasons.

Step 2:

[Formula is omitted from this preview]

3.4 Login Phase

In our login phase when the register user want to get the real time sensor information, they execute some steps of this login message, sending these information to GN via an unreliable way The details of this phase are specified in figure 3.3 and underneath:

Step 1:

[Formula is omitted from this preview]

Step 2:

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3.2: User Registration Phase of Proposed Scheme

3.5 Authentication and Session Key Agreement Phase

In the subject phase mutual authentication as well as session key agreement are executed between Ui, GN and SN the detail of this phase is illustrated in figure 3.3.

Step 1:

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Step 2:

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Step 3:

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Step 4:

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Step 5:

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Step 6:

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Step 7:

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This protocol then establish session key SKui = SKSN = SKGN between Ui, SN and GN after mutual authentication. The main purpose of this scheme in this phase is the negotiation of the session key SKui = SK SN = SKGN among the above three main entities.

[Formula is omitted from this preview]

Figure 3.3: Login and Authentication Phase of Proposed Scheme 27

3.6 Post Deployment Phase

The key purpose of post deployment phase is the deployment of sensor-nodes later the accomplishment of the sensor network. There is a practical issue in this phase when one or many sensor node becomes damaged so requisite replacement of the same is necessary. Suppose that a damage nodeSNd require to be change with fresh sensor node SNf in the target area.

[Formula is omitted from this preview]

Now, SA deploys SNf on the target field. After deployment the SNf computes the registration phase of the sensor node as represent in figure in the previous section.

3.7 Identity Update Phase

The main purpose of the above subject phase is the enhancement of security to updates the identity of the register user with the assistance of GN. Ui enter the smart-card in the card-reader and computes the step 1 of the proposed login phase to confirm U i authenticity. Now the Smart-card and Ui performed the underneath steps:

Step 1:

[Formula is omitted from this preview]

Step 2:

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Step 3:

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3.8 Password Change Phase

In password based authentication protocol must include password modification the concerned user Ui any time change their password for the enhancement of security without the assistance of SA or GN. The detail specification of this phase is narrated as under:-

Step 1: U i entered the smart-card within the card-reader and re-process step 1 of the login phase checked the legitimacy of identity, password and fingerprints.

Step 2:

[Formula is omitted from this preview]

Step 3: Smart-card update the old record (eui, gui, fui) with new {enew ui , gnew ui , fnew ui } in smartcard memory. The other factors remain unchanged.

3.9 Smart-card Revocation Phase

In the practical issue when the register user Ui of the network smart-card is misplace or stolen so in this protocol user obtained the new smart-card with the computation of the following steps.

Step 1: U i send his/her identity IDui alongwith personal information to the SA via a reliable channel. SA verify Ui personal credentials of the user if valid then computes:dnew i = h(IDui//XGN) and Lnew i = h(SCNnew//XGN), SCNnew is a unique number of new smart-card. The SA keeps {dnew i , Lnew i , SCNnew,BK()} in the new smart-card memory and send it securely to user. SA modify the Database with SCNnew.

Step 2:

[Formula is omitted from this preview]

3.10 Chapter Summary

We presented the features of proposed protocol in this chapter with their significant nine phases to avoid the user anonymity and traceablity attack which has already been discussed in cryptanalysis in chapter 2. In this chapter, we also present the dealings to avoid all possible attacks and make the user hidden (anonymous) on the same protocol. In the cryptanalysis we have already examined and declare the two categories of threats and user anonymity breach of the R. Amin et al. protocol. After that we presented several principles for safety of the protocols. We also presented some approaches for scheming the security protocols and then we tried to improve the protocol with the procedures offered. Numeral examples in the literature have also been made known that the work completed in the document is especially momentous.

Chapter 4 Security Analysis

In this chapter we evaluate and examine the safety features and robustness of the intended improved authentication protocol. We are considering this security measurement in the light of adversarial model which we discussed in chapter 1. Moreover in the next subsection we examined that the proposed protocol is strong/healthy against all possible attacks of the adversary or not. In addition, described the comparison and security requirements of proposed protocol. Since, considerate thoughts of cryptographic protocols required so that we are capable to observe the information about protocol contestants and challenger. Upon receiving a message by the opponents:

1. Does he/she identify that who sends it?

2. Does he/she recognize that the message is fresh?

3. Does he/she know that it is never just a repetition of something from the past message?

4. Does the system investigator identify who is communicating to whom?

The security analysis of the proposed protocol can be divided into two categories formally and informally.

4.1 Formal Security Analysis

In web technology communication not only share the information among the entities but they have some rules for their communication which known as protocols. So the security of these protocols is very important for the secure sharing of information. In any regulations manipulating, cryptographic functions also desirable for several explicit problems solution 31 within a protocol. The proper security examination of the novel protocol has been verified by using ProVerif and BAN logic.

4.1.1 Security Analysis with BAN logic

In this part we presented the authentication of our proposed scheme through proper security examination by using a tool BAN-Logic. This tool was first published in 1989 by Burrows, Abadi and Needham. This was the first idea for the inspection and descriptions of authentication schemes. It is a valuable tool that expresses the impression of truthful parties engaged in the communication as well progression of these trusts as a outcome of communication. The conservative technique for the description of these protocols, by catalog the destination, source and contents symbolically, is change with logical principle. This representation goal to prepare the protocol all steps in a method that all the necessary information expand from the step is revealed. This is known as idealization of the procedure. Additionally, the idealized protocol is interpreted with declaration, which typically describes the beliefs of the rule at that spot of the protocol. At the similar time the protocol is investigate step by step using some set of assumption rules [31]. There are some special notations use for BAN Logic for the description of the logic, suppose sign P and Q denote the principals X and Y are the sort over the declaration and K be the Cryptography key. The most frequently used concepts and some symbol of BAN-Logic, are describe as under:

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Table 4.1: Notations and Concepts in BAN-Logic

4.1.2 Rules of BAN-Logic

Burrows, Abadi and Needham were define varies rules for the authentication of protocols. As per these defined rule if only one rule violate, then that protocol should be understood erroneous one. The descriptions of these rules are as under:-

Principals: Those individuals who are concerned in the protocol (typically people or plans).

Keys: It use for encryption of messages symmetrically.

Public Keys: It is also a key but it used in a pairs.

Nonces: It is a random numbers or part of messages which are not repeated.

Timestamps: It is the recent time of a happening that are unluckily to be repetitive.

Rule 1: Message Meaning

[Formula is omitted from this preview]

It shows that if P obtain the X encoded with Key K and P deems K is fine key to communicate with Q, and then P believes Q said X.

Rule 2: Nonce Verification

[Formula is omitted from this preview]

When a principal P trusted that X is new/fresh also then principal Q only once time sends X after that Principal after that P believe Q held X.

Rule 3: Jurisdiction

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Principal P believes that Q have control/jurisdiction on X also P believes that Q believes X, after that P trusted that X is right.

Rule 4: Acceptance Conjuncatenation

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If a principal P is believes X as well as Y, subsequently then principal P also believes on (X, Y).

Rule 5: Freshness Conjuncatenation

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If a principal P confident that X is a fresh, after that a principal P also believes newness / freshness of (X, Y).

Rule 6: Session Key

[Formula is omitted from this preview]

If a principal P believe the fresh session key also then principal P as well Q also believes on X which is the essential constraint of a session key, next principal P also believes that he/she share a session key K with Q.

4.1.3 BAN Logic Procedure for Protocol Analysis

To institute proposed protocol is safe, the given procedure should be exercised.

- In the first step idealize the planned authentication protocol in a formal logic of the language.

- In the second step recognize the assumption regarding the preliminary state of proposed authentication protocol.

- In third step utilize the production and utilize the rule of a logic to infer new predicates.

- In fourth step use the logic to find out the beliefs apprehended by the entities within the proposed proposal. In order to verify the proposed scheme safe, the proposed scheme be required to satisfy the below goals which depend on the mechanism of BAN-Logic which are specified as under

[Formula is omitted from this preview]

Part 1: The proposed protocol Idealized form are as under:

[Formula is omitted from this preview]

Part 2: Assumptions for analysis the protocol are as under:

[Formula is omitted from this preview]

Part 3: Analysis based on Assumptions and BAN Logic Rules which is stated as under:

[Formulas are omitted from this preview]

The proposed scheme make sure by using the verification tool BAN Logic which show that all the three participant entities Ui, GN and SN successfully achieve the session key agreement 37 and mutual authentication.

4.1.4 ProVerif

ProVerif is verification tool which use for assessment and robustness of the protocols against all possible active attack. The same tool kit is also examine the insider attack which known some cryptographic parameters. This verification tool analyzes the protocol against strong adversaries attacks from all angles. ProVerif can verify various security elements, for example: traceability, anonymity, reachability, secrecy and authentication [14]. ProVerif is based on pi calculus which uses logical and arithmetic procedure. ProVerif tool having the given three elements: declaration, process also main part. The first part is used for defining variable cryptographic primal and contents. As illustrated in the figure, we actually define tow channel private and public.

[Protocols are omitted from this preview]

4.2 Informal Security Analysis

In this part of security scrutiny we check the robustness, accuracy and security of the proposed protocol against all possible attacked, specially mentioned in chapter 3 of the thesis. Our proposed scheme is verified that this protocol is tackling all possible well-known attacks. Deem an adversary can interrupt a system, which can change the communication information, copy a part of communications message, resend the messages, or deliver false objects etc. This hypothesis is collective for everybody and also more sensible in modern era. Our proposed scheme accomplished the following possible security hazard which is narrated as under:

4.2.1 User Anonymity

As identity protection and privacy concern is growing among the individuals. As in private and government organization the privacy and anonymity is important research topic in the recent era. In distant authentication protocol the user anonymity is define as who is the Initiator, Transmitter anonymity more specifically means that the opponent might not have the information of the actual identification of the originator but may recognize whether two dialogue initiate from the similar (unidentified) entity. So this protocol protect the individual personal information to accomplished user anonymity [32]. Here in Amin et al.'s protocol, the SCTx is transmitted over the public channel, thus

[Formula is omitted from this preview]

in this message the unique smartcard number SCN is transmitted in plain. Hence from this message the initiator/sender information may breach so this problem may lead to violation of user anonymity such as:

[Formula is not in the preview]

But here in the proposed protocol we encrypted the unique smartcard number SCN with private key of GN and then send on the public channel:-SCNj = XGN(SCN //ri) then send SCNj in encrypted form. The adversary A may possibly attempt for the extraction of the identity IDui of the user U i wither for the public channel or from the smartcard. However the same is infeasible for the adversary A because of the identity protection by different means in the proposed protocol. Thus the above discussions reveal that our scheme can resist the user anonymity and off-line ID guessing attack.

4.2.2 User Untraceability

User traceability is vulnerable issue for secure authentication protocol because traceability may lead different attacks. A interrupt two dissimilar communications from the dissimilar sessions and test that they are equal. If same A trust that both messages send by the similar user. A cannot seize one or extra public messages, because the random number and timestamps is different in every session as well the login messages of every session are besides different. Hence, our protocol opposes user un-traceability attacks.

4.2.3 Stolen smart-card attack

In the stolen smartcard attack A getting the confidential information from the smartcard by using the mechanism of extracting information given [33][34]. Assume that normally Ui using low entropy using only ID and password, imagine that guess or find out in a polynomial time. But A try not just to extract secret information, however it need to get ID and password which is not possible in this protocol because of the following properties:- Suppose A extract the smartcard information (Bui, eui, fui, gui, SCN ,BK()) from the smartcard but these parameters are encrypted with XOR operation and simple hash function, whereas

[Formula is omitted from this preview]

it show that di unidentified to A in the same way A cannot compute gui without the value of Li because these value are secured by hash function.Therefore A is not able to extract successful the required value due to unpredictability of hash function In view of the above it is so clear that the attacker not able to get the confidential information from the stolen smartcard. So, our scheme is safe against the stolen smartcard attack.

4.2.4 Replay Attack

In cryptography, opposing the replay attack is pretty hard. In our novel scheme the adversary may possibly try to forge older messages with no changes of the communicating participant e.g. (user, gate-way node and the sensor-node). In broad, the timestamp techniques are used for the resistance of replay attacks, but maintain time synchronization crosswise huge networks is pretty complicated. It must be remember that WSN network are applied on a particular area, so reducing the same time synchronization issue. Hence, the timestamp method can only be applied for GN andSN. We use the timestamp mechanism in GN and 44 SN, where GN and SN verify the validity of the time-stamps by computing at all security restriction. If A make fakes the earlier messages of the communicating participant, the protocol close-up the link due to invalid timestamp. Still, preserving time synchronization within big net works is tough. Particularly, the access of users services from some-where, or from the communication infrastructure. So, the timestamp techniques are not suitable for tackling replay attacks especially involving user. While the protocol cannot use the time-stamp mechanism among the users and the getaway nodes, A may possibly try to instigate the replay attack, although will be unsuccessful because: 1. Suppose that A replays the older message MSG1 = (M1,M2,M3, T1, SCTx , EIDSN) to GN without any alterations. 2. It is well-known that the repeated messages should be authenticated byGN. In our protocol, GN send out MSG2 = (M4,M5) to Ui GN andSN suppose that A interrupt MSG2 = (M4 ,M5) this message from the unreliable channel. 3. A computes a valid M6, which is contingent on the identity IDui, secret parameter di as well the random no ri. We already shown that A has not capable to get IDui, ri, d i, as A is not able to get any information, calculations of the valid M6 is not possible. A convey M6 to GN after deduction the necessary parameters, GN finish the link because M6 is invalid.

4.2.5 Off-line password guessing attack

Similar to the identity guessing in off-line, A be able to get the password of a user Ui in polynomial time. In this scheme, we have verified that A is not capable to find out the password PWui of Ui by means of smart-card information. Especially, the public channel messages of the novel scheme are free from PWui. Thus, finding or extracting PWui from the messages of the public channel is unrealistic in our protocol.

4.2.6 User-impersonation attack

In this kind of attack A interrupt the login credential of the protocol, in that case A attempt to formulate another fake login message. But here in the proposed protocol A is unable to do so. Suppose A interrupt the login message

[Formula is omitted from this preview]

So it show that A can take a new random number 45 with time timestamp but A needs the identity of user IDui, sensor node IDSN as well the L i to compute the afore mentioned values respectively. In this regard A needs di to computes M2,M3 so A is not able to extract the same without the ( IDui, IDSN, di). Therefore, our scheme provides security against user-impersonation attack.

4.2.7 Gateway node impersonation attack

This attack is same like the user impersonation attack, in which A might attempt to masquerade as GN after interrupting validation messages during the execution of the protocol. So to do so the same, A require to computes (M4, IDGN,M7,M8,M9, T2), where

[Formula is omitted from this preview]

Thus A require (IDui, IDSN, SSN) for the computation of M7,M8 and M9 respectively. Since these identities ( IDui, IDSN, SSN) are unidentified so it show that it is infeasible to compute other successful forge authentication message. Hence, this protocol provides full security against gateway node impersonation.

4.2.8 Sensor node impersonation attack

Just like gateway node impersonation attack the sensor node SN may also impersonated by A after erupting the authentication message.A needs to create

[Formula is omitted from this preview]

Therefore,A needs (IDui, IDSN,X SN, ri) to calculate MSG5 = (M 10,M11, T3). While A has still no knowledge about the (IDui, IDSN, S SN, ri), so it is impossible to lunch the sensor node impersonation attack.

4.2.9 Privileged-insider attack

If the malicious user or an insider of the organization obtains the user password by various means, he or she lunched a privileged-insider attack to break other schemes by using the same password and identity to register. The malicious users generally utilize the same identity and password for sets of servers. As per the information of the literature, the majority security schemes are susceptible to this insider attack. So, this attack is a vital attack in password-based authentication schemes. During the registration of the user in our scheme, Ui sends onlyIDui in registration phase public messages are free of Ui password. Hence, an insider malicious user has no way to get Ui password. 46

4.2.10 Session key computation attack

In this authentication protocol the session key is obviously use for encryption of secret information the transmissions of message between the entities on unreliable channel. The key characteristic of the session key is novelty and freshness, so it means that the session key should be different for every session. In our proposed scheme, Ui,GN and SN negotiate the sessions key

[Formula is omitted from this preview]

that trust on the secret message (IDui, IDSN, ri, rj) that are unidentified to A. Thus A not capable to extract the requisite session key without the knowledge of (IDui, IDSN, r i, rj). Moreover, the session key in this scheme having the freshness quality because of using these random numbers ( ri, rj).

4.2.11 Verification of the session key

Session key negotiation is verified at the time of protocol execution. In authentication phase of the protocol GN verify the session key SKSN generated by the sensor nod SN with the confirmation whether M/ 10 = M10 holds. Subsequently Ui authenticated that whether M /10 = M10 holds for verification of the session key SKGN which is created by GN. Hence the proposed protocol also provides the property of session key verification.

4.2.12 Mutual Authentication

For secure communication when public message passes over unreliable channel, so mutual authentication between the participant entities must be provided. In this scheme during the protocol execution each member authenticates other. Because authentication is property of security in which all participants of a protocol uniformly authenticates each other at matching time. Our protocol achieves every circumstances of mutual authentication moreover, our protocol furnished proper mutual authentication among the entire three participant entities U i, GN and SN.

4.2.13 Man-in-Middle attack

It is that type of security attack in which a malicious user or attacker illegally entered in communication between the two parties and interrupt the communication. The adversary completely captured the secret information also can send or receive messages any time by impersonating both communicating parties by imagining itself a legal user of the organization. 47 In our proposed protocol the attacker or the adversaries not able to do the Man-In-Middle attack because in our proposed protocol exist mutual authentication on each side of endpoint. We use timestamps with every message also the time difference is checked at end point if valid then proceed the communication or otherwise. We also use random number so adversary not-able to guess any public key or secret random number from which attacker can find out the session key moreover, our session key establishment is completely fair. Hence, our proposed scheme can protect the Man-In-Middle attacks.

4.2.14 Protection of unauthorized login

The user un-intentionally tries to enter incorrect information at the smart-card device during the login phase. Due to this wrong information the protocol perform additional computation and the congestion of network rising. Therefore, in this initial stage wrong information should be protected at login phase to avoid additional execution of protocol. Hence the terminal should not create a login message without authentication of a user legality. So in our scheme the likelihood of providing erroneous information is not possible in biometric information/data instead of password information. Though if user given the wrong finger-printfngi then the condition in the login phase (B * ui _= Bui) not hold then the session abort, whereas

[Formula is omitted from this preview]

Suppose that Ui enter the right finger-print, however in case of password when enter the incorrect password PWui, the smart-card can reject the user login message, because

[Formula is omitted from this preview]

4.2.15 Provision of Post-deployment phase

This phase is essential when the sensor node on the target region may occur damage due to some way so it needs to replace the same. Moreover the target area some time needs to expend the network. So SA deploy the requisite sensor nodes and expanded the target field, for the provision of this facility the addendum scheme offer this post deployment phase to do so.

4.3 Chapter Summary

In this chapter we examine the security assessment of proposed scheme that how to do its function in look of aggressive intruder. In generally we discuss two types of security analysis; formal and informal that may possibly or may not formulate use of automatic tools. In formal analysis we used the ProVerif tool for which using the pi-calculus for checking the protocol security and robustness. In informal analysis offers less assertion than the formal. Despite that it is also may give better scope, because there are security weaknesses that still we are not able to know how to model mathematically. So a formal analysis offers a large degree of guarantee than an informal analysis, but it only trusts on hypothesis regarding the cryptographic algorithms exercise that could not be probable to verify.

Chapter 5 Performance and Security comparison

In this chapter we assist and determine various characteristics, such as computational cost, communication cost and storage cost of the proposed scheme and compare with the previous related already existing protocols [1,2,5,30]. We have shown the result of the proposed and previous protocol in the tables 5.1, 5.2, 5.3, 5.4 for the measurement of clear efficiency of our protocol. The novel protocol resists all known threats, having the requisite functionality but with some high complexity. We examine the efficiency of proposed protocol in the following terms:

- Security features comparison

- Computational Cost

- Communication Cost

- Storage Cost

5.1 Security features comparison

The comparison of propose scheme are shown in the following table in which the proposed scheme resist all known threats. We compared all 13 requisite security features of our proposed protocol with the previous related schemes [1,2,5,30] whereas, R is resistance against possible threats which started from R1 and so on. The comparison table shows that only our scheme provides all 13 requirements. The detailed comparison is shown in table.

[Table is omitted from this preview]

Table 5.1: Security requirements table

5.2 Computation Cost Analysis

Energy consumption is a big issue in WSN therefore, we use mostly simple hash function and XOR operations. The computation cost of a few lightweight function such as XOR operations and concatenations are so small due to its tiny computation cost so we ignore these lightweight functions. Our main concentration is to scrutinize cryptographic functions that Ui, SN and GN require to execute. One-way hash function is simple to implement also take small time as compare to other operations. The symmetric encryption and decryption takes three time more cost than hash operation [2], Amin et al. [1]has not been using encryption/decryption but in our proposed scheme we use one time symmetric encryption/decryption to secure the security loophole of Amin et al. scheme therefore the running time of our proposed scheme is slightly greater than Amin et al. [1] as shown in the table 5.2. We deem all three contributor Ui, SN and GN. Detailed explanation is illustrated in table the given notations are used:

- CC:Computation cost

- Th: CC of single hash function;

- Tse: CC of symmetric encryption;

- Tsd: CC of symmetric decryption;

5.3 Communication Cost Analysis

In this subsection we present the communication cost of our proposed protocol. The communication cost of any protocol is depending on extent of received and conveys messages. When the network congestion are reduced and the communication message is transmitted swiftly then the communication cost also become low down as possible. In our proposed scheme U i transmit 896 bits and received 384 bits, GN transmit 1152 bits and received 1280 bits and SN transmit 384 bits and received 640 bits. So, the overall communication cost of U i, GN and SN are1280, 2304 and 1024 bits respectively. The communication cost is actually the cycle of victorious communication of messages which exchange between the user and IOT part means sensor nodes and gateway node (WSN). So our proposed scheme contained total 6 messages/steps during successful execution. We summarize the communication cost comparison of our proposed protocol with other related protocol in table 5.3 which almost better than [2,5,30] but the communicational cost of proposed scheme almost similar with the Amin et al.[1] scheme because the transmission and receiving of bits are same among the entities as well the exchanging of messages also same.

[Table is omitted from this preview]

Table 5.2: Comparison of computation cost and running time

5.4 Storage Cost Analysis

The requisite property of our proposed scheme to reduce the storage cost of smart car and the sensor-node. So, the storage cost of the sensor-node and user smart card are very small than the gateway node of the proposed protocol.

[Table is omitted from this preview]

Table 5.3: Communication Cost of Proposed and other Protocol

Energy conservation is the big issue in WSN so the sensor node communication cost should be minimum. We analyze the storage cost especially at the sensor node. The storage cost is higher in [5] but in the other comparative scheme [1,2] the storage cost is relatively same. We preferred MD5 therefore, we imagine that the size of password, identity, hash function and random number are 128 bits. Hence the smart card storage our protocol is relatively equal to [1,2] as shown in the Table 5.4.

5.5 Chapter Summary

In this chapter we represented the efficiency of the proposed scheme and compare the same with the previous related scheme. The result of proposed scheme is analyze in the term of computation cost, communication cost and storage cost. All the performance are shown in the appropriate tables.

Chapter 6 Conclusion and Future Work

In this thesis, we inspected Amin et al.'s protocol in which we examined that this protocol having some security loopholes in terms of anonymity and traceability attacks. In order to protect the security flaws of the said protocol, this thesis has primarily accomplished a novel robust light weight three-factor user authentication and session key agreement protocol for WSNs in which the user can securely access the real time information from the IOT environment. Moreover, to verify its security perfection, we simulated the novel protocol in BAN-Logic and most popular accepted security simulation tool ProVerif. The results of this enhanced protocol show that the same protocol provides security against all active as well passive attacks. Likewise, informal security analysis and comparison also revealed that this improved scheme is safe against all threat. High communication and computation cost are major challenges in authentication of WSN based IoT. In future our goal is to work on the efficiency of WSN in terms of low communication and computation cost in WSN environment.


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ISBN (Book)
File size
1.4 MB
Catalog Number
Wireless Sensor Networks Three-factor Authentication Key Exchange IOT WSN




Title: An Improved and Anonymous Three-factor Authentication Key Exchange Protocol for Wireless Sensor Networks