Password-based authentication schemes consider the most widespread protocol used to validate authentication between legitimate customers and the remote server. The single-factor authentication (SFA) considers the first process for securing access to a specified system, such as a web site or e-business system, that identifies the party demanding access over only one type of credential. One of the major worries with passwords is that users face many challenges to understand how to make robust and remarkable passwords, or undervalue the need for security. Furthermore, most users tend to select something such as phone numbers, birthdays, favorite games, and names of movies. These matters are easy to memorize. Accordingly, adversaries can build a table of important words in order to enter the system by applying a dictionary attack. Additionally, these passwords can be broken in a matter of a few short minutes. As a result, this type of password can be detected from a simple note, either in use or heedlessly rejected. While those ways need to be secured against, passwords are also required to be less predictable by machines. Moreover, the predications of password entropy mean how difficult an obtained password would be to crack via guessing, dictionary, brute force cracking attacks or other well-known schemes. In short, passwords are still one of the most simply stolen/broken categories of authentication. Multi-factor authentication (MFA) collects two or more separate credentials: what a user knows (PIN), what a user has (smart card) and what a user is (fingerprint). The purpose of MFA is to generate a layered protection and make it more troublesome for an illegal person to arrive at a target such as a server, computing device, web system, or network. If one factor is assumed to be disclosed or detected, the adversary still has at least one more fence to get around before successfully reaching the target. On the other side, the typical costs for prevailing multi-factor authentication techniques are a little money per month, per device. However, this can add up to thousands of dollars per year for budget companies that have a lot of customers or devices, or both. Obviously, multi-factor authentication tools are worthwhile, principally as the number of passwords continues to rise and make headlines. Businesses have been set-up to provide better methods to preserve user login information beyond an easy username/password mixture [1
Furthermore, there are many challenging issues that raise concerns about using multi-factor authentication including the high costs, not being easy to carry, not providing the functionalities of revocation, and failing to resist well-known attacks such as off-line guessing of passwords, Man-in-the-Middle (MITM), and user/server impersonation attacks. Principally, the user’s password refers to the first factor while the second factor can be one of tokens, smart cards, fingerprints, voices, etc. Only the genuine user has registered his second factor to the server in advance. However, the token cannot resist the MITM seed-tracing, comes at a high cost, and when it is lost or stolen, the service provider security may be compromised. Furthermore, how to arrange tokens issued by several servers is a big problem for both users and servers. The shortcomings of users’ biometric factors, when a large number of users try to authenticate in the system at the same time, the mechanism of the system becomes unacceptably slow.
Moreover, biometric factors require extra hardware and software. In this paper, we propose a strong scheme based on smart card and feature extraction of hand geometry to overcome the above-mentioned issues. Therefore, this section introduces biometrics features and smart cards, and then explains the main goals of this paper that lead to the presentation of our proposed scheme [1
Accountability with articular authentication is significant for security in the communication world. Several physiological features of humans such as biometrics, are characteristically time stable, easy to acquire, and unique for every individual. Biometric features such as palm prints, handwriting, signatures, fingerprints, irises, faces, and hand geometry have been proposed for security in many fields such as access control, authentication, and authorization. There is a lot of research focused on fingerprints and faces [6
]. The trustworthiness of personal identification applied to the face is considered low, as researchers currently continue to fight with the issues of orientations, gestures, poses, and lighting [2
]. Fingerprint identification is extensively used in biometric identification, as it leads to good results in most cases. Conversely, it is not easy to obtain fingerprint features such as minutiae for elderly people. Minutiae indicate specific points of user’s fingerprints, the small details of user’s fingerprints that are most significant for fingerprint recognition.
Consequently, other biometric characteristics receive more attention for personal identification. Similarly, additional biometric features like hand geometry, can be easily added into the current authentication scheme to provide an improved level of reliability in personal authentication.
There are several authentication schemes that are proposed in [8
] to use the smart card as a second authentication factor. Das et al. [14
] proposed a scheme that is secure against replay attack, password guessing attacks, forgery attacks, dictionary attacks and identity theft. The researchers [15
] denoted drawbacks of Das et al.’s scheme, which suffers from disclosing the identity of user’s authentication messages. Shih [16
] also explained that Liou et al.’s [15
] scheme cannot achieve mutual authentication and fails to resist off-line password guessing attacks. Xu–Zhu–Feng [3
] refers to a forgery attack on Lee–Chiu’s scheme [17
], and Lee–Kim–Yoo’s scheme [18
] cannot resist the password dictionary attack. Additionally, Wang et al. [19
] describe weaknesses of the schemes proposed by Kumar [20
] and Awasthi-Lal [12
]. Currently, Chun-Ta et al. [21
] presented an improved scheme of Khan et al. [22
] that fails to preserve user’s anonymity. Continuously, their improved scheme can satisfy several of the main security and functionality features for remote login systems. However, it also cannot support the biometric factor for enabling the revocation feature when the valid user loses his smart card or gets its stolen.
Regarding the advantages of biometric factors, the low value of secret-key entropy is the fault of biometric factors, which can be hacked in polynomial time. For instance, there is no way to avoid an adversary from applying his impersonation attack to the victim user if both the user’s password and smart card were lost/stolen. Therefore, several schemes [16
] ensure the security of the system when either his password or his smart card is lost/stolen, but not both of them at the same time. On the opposite side, there is a sturdy secret key that combines smart cards and biometrics with passwords (called Multi-Factor Authentication (MFA)) that enjoy high entropy. Furthermore, the essential feature of the biometric is uniqueness in that everybody has various sources of biometrics such as fingerprints and eye recognition, and it is hard for genuine user’s biometrics to be lost/stolen because only the actual user enters personal biometrics with his smart card to login to the system. There are many schemes based on biometrics with smart cards [9
], but these schemes require extra hardware and software for each login phase.
Moreover, smart cards are considered small devices and require low computation capability, mingy energy resources and small memory size. It is more desirable to only use symmetric-key manners such as crypto-hash functions, symmetric encryptions instead of applying costly asymmetric cryptographic schemes. Moreover, smart cards are generally widespread in sensitive environments such as bank services and health-care. On the other hand, the conventional security risks are exposed to many malicious attacks and are prone to more dangerous attacks. As a result, an esteemed multi-factor authentication scheme for smart cards should be able to prevent various common malicious attacks like insider, impersonation, MITM, replay and online/offline password guessing.
Additionally, the privacy of users is considered very important in the smart card industry. There is an imperious need for preserving user’s data access privacy, when important data is submitted in the login phase, and what data types the user is interested in, since the infiltration of such information could be hard-done by an adversary to use it when the legal user logout the system. There is an increasing demand for preserving user privacy information from being leaked and abused, which borders the needs for protecting strong schemes that can acquire asymmetric-key encryption, preserving user’s privacy, and user anonymity [19
Furthermore, imposing efforts have been focused on producing schemes with user anonymity by only applying lightweight symmetric-key primitives like crypto hash functions and modern block ciphers. In this paper, we focus on two parts. In the first part, we analyze Xue et al.’s scheme, and present the main challenges in designing an authentication scheme with user anonymity. In the second part, we refer to the practical solutions for using user anonymity in our proposed scheme.
Additionally, we embed users’ hand geometry features as a biometric factor with the smart card in an effective manner that does not require extra hardware and software in the login phase. In the registration phase, a user submits his hand geometry and hashed user name and password into the server. Then, the server extracts the features of hand geometry and sends back the features, and smart card to the user. After that, the user keeps his hand geometry features in his USB to use in the next phases. Therefore, the adversary will have difficulty obtaining the user’s smart card and USB for applying malicious attacks. Furthermore, we review a security analysis of the Xu–Zhu–Feng scheme that is not immune to password guessing attacks and impersonation attacks. We also propose a new efficient and secure smart card based on a remote password authentication scheme that overcomes not only the weaknesses of the Xu–Zhu–Feng scheme, but also enjoys several features such as efficiency, flexible password-based remote mutual authentication, user anonymity, users being able to freely select and update their passwords, and the server and user being able to construct authenticated session keys. In fact, our scheme generates a key once for each user’s login request in the authentication phase. Moreover, our scheme can resist many kinds of attacks such as replay attacks, insider attacks, off-line attacks, reflection attacks, and DOS attacks. Continuously, compared with the other related schemes, our work is powerful both in communications and computation costs.
The remainder of the paper is organized as follows. Section 2
reviews the Xu–Zhu–Feng scheme. Feature extraction of hand geometry and design issues of the proposed scheme are discussed in Section 3
. Our proposed scheme is presented in Section 4
. Security analysis is reviewed in Section 5
, and Section 6
presents the discussion and comparison with state-of-the-art methods. Section 7
provides our conclusions.
5. Security Analysis of Our Proposed Scheme
In this section, we analyze our proposed scheme and display that our work can withstand several famous attacks and enjoy several security properties. Moreover, we supply a comparative analysis with other authentication schemes.
Our proposed scheme can support mutual authentication.
A mutual authentication feature requires both the server and the user to authenticate each other. In our work, authentication of to S is represented by . In addition, the authentication of to S depends on generating a new key . After that, the user computes . An adversary is not able to generate . In addition, and S securely exchange and in the login and authentication phases, respectively. The authenticated session key is demonstrated as follows:
. Thus, our proposed scheme provides mutual authentication (see Figure 5
Our proposed scheme can support known-key security.
The definition of known-key security is that the jeopardy of a session key will not lead to further endangerment of other session keys. However, if a session key is exposed to an attacker, he incapacitates inferring other session keys that are produced from the random numbers and the dependent Diffie–Hellman key exchange scheme. In addition, it is impossible for an attacker to get a server’s secret key . Furthermore, if we assume that an adversary can eavesdrop on , he cannot gain any advantages from eavesdropping on . Thus, it generates one time for each user login request. ☐
Our proposed scheme can support user anonymity.
If an attacker eavesdrops on the user’s login request message, he fails to infer the user’s identity from encrypting message , since it is encrypted with , which is anonymous to the attacker. In addition, the ciphertext does not possess the real user’s identity where the server verifies the user’s identity in an anonymous manner between and . Additionally, we used the time-stamp in the login phase; the user’s login request message is changed each login time when its parameters change in each login session. Therefore, it is impossible for the attacker to reveal the user’s identity. Obviously, our proposed scheme can support user anonymity. ☐
Our proposed scheme can support revocation of smart cards and also does not require extra hardware and software, as it resists side-channel attacks.
If a user’s smart card is lost or stolen, an adversary cannot derive or change the password because he fails to pass the biometric verification. In addition, the secret information saved on the user’s smart card is as robust as the password. In the login phase, the user inputs his biometric key which is saved in his USB. Compared with Chuang et al.’s scheme in [9
], their scheme needs extra hardware and software to complete the verification of a user’s biometric. Our scheme requires a USB device that is available in most of the terminate machines and focuses on features of hand geometry for increasing performance and decreasing costs.
Side-channel attacks commonly exploit the presence of data-dependent and physically noticeable phenomenons caused by the implementation of computing functions in microelectronics [40
]. The main examples of such information outflows are comprised of power consumption and the electromagnetic radioactivity of integrated circuits. We focus on side-channel analysis against subscriber identity module (SIM) cards in smart cards that our proposed scheme does not cause overloading on smart cards because the important information of users was saved on USBs. Our proposed scheme retrieves
from a smart card that connects with a USB’s information to complete the login and authentication phase. Therefore, an adversary cannot complete the login phase even if he already has the smart card because the rest of the information has been previously saved in the USB. Eventually, the performance of the smart card is very high since the power consumption of the device is very low. ☐
Our proposed scheme can support security of the stored data and resist a password guessing attack.
In our proposed scheme, the remote server S stores only secret information in the smart card. The secret information derived from the user’s smart card does not assist an attacker without the user’s password , the user’s personal biometric (hand geometry ) and server’s secret key to retrieve the user’s secret key , since and . If an attacker is attempting to retrieve by combining dictionary attacks with the recover secret information , he requires locating both and to compute . On the other hand, the attacker can gain by eavesdropping on the insecure channel between and S. The attacker cannot get useful information about the user’s password/hand geometry from these values because other information is encrypted by the user’s secret key and only the user can access his biometric key. Thus, our proposed scheme provides security of the stored data and resists a password guessing attack. ☐
Our proposed scheme can resist the server impersonation attack.
A user’s smart card contains two values: and . Since the user knows his password and his biometric key , he can obtain the value of . However, this value is based on the user’s identity, and it is not the same for all users. The attacker cannot play the role of the server with this value and fails to get the values . They are used to decrypt the ciphertext sent by , where is computed by . Therefore, the proposed scheme can resist the server impersonation attack. ☐
Our proposed scheme can withstand insider attacks and user impersonation attacks.
In our proposed scheme, when wishes to register with a remote server, he sends instead of . Due to the utilization of the one-way hash function h(.), it is difficult for the server to extract the password of the user from the hashed value. In addition, when the attacker wants to impersonate the valid user, he requires the forging of a legal login request message , in which . However, the attacker cannot obtain the server’s secret key and fails to forge such a message or obtain a user’s biometric key. Clearly, our proposed scheme resists insider attacks and user impersonation attacks. ☐
Our proposed scheme can resist DOS attack.
This attack means that an attacker changes the password verification information of a user’s smart card to other information. As a result, an illegal user cannot complete his login to the server request successfully. In our proposed scheme, a user’s smart card checks the legitimacy of a user’s biometric key based on hand geometry , user identity and password before the password change phase. If we assume that the attacker inserts the user’s smart card into the terminated machine, he must guess the values of the user identity and password. These values are not stored directly in the smart card, but they are combined with other values, e.g., , where are not stored in the smart card. Additionally, an attacker cannot access the features of a user’s hand geometry saved on his preferred USB. Therefore, the attacker cannot obtain to apply a DOS attack. ☐
Our proposed scheme can resist a replay attack.
In our proposed scheme, the user’s login request message combines a random number with the time-stamp T to protect a login message from replay attack. However, if an attacker eavesdrops on a user’s previous login message, he still cannot apply a replay attack to the next login request since combines several values with the time-stamp T. The attacker cannot get these values, and generates one time for each user’s login request. ☐
Our proposed scheme can withstand a parallel-session attack.
In our work, an attacker cannot impersonate a valid user by constructing a legal login message in another continuous execution from the authentic execution since the server’s submitted message is encrypted by , which is anonymous to the attacker and generates one time for each mutual authentication phase. Hence, our proposed scheme can withstand the parallel-session attack. ☐
Our proposed scheme can resist the common attacks when a USB device is lost or stolen.
If a user’s USB is lost or stolen, an adversary cannot complete the login or authentication phase because he fails to get the smart card, , , and . In addition, the secret information saved on the user’s smart card is as robust as the password. Our scheme requires a USB, and a user’s password and smart card to apply to the login phase. First, a user submits his message to the server. Continuously, the server checks the validity of users and he will send a challenge () to the user. After that, the authenticated user should retrieve to decrypt M based on . Additionally, he computes for comparison with to ensure authority of the server. Therefore, the adversary cannot apply malicious attacks when the USB is lost or stolen. ☐
As a result, we notice that the proposed scheme is more robust and flexible for practical applications such as online payment environments and e-business in protecting user privacy compared with other related schemes. Additionally, we propose a good authentication scheme based on a smart card and feature extraction of a user’s hand geometry. The proposed scheme aims to support more functionality to resist well-known attacks and provides several security features such as revocation, user anonymity, known-key security, and mutual authentication. The mechanism of the proposed scheme can be compatible with ubiquitous computing models such as cloud computing. Additionally, a USB provides a biometric factor for multi-factor authentication.