In 2004, Das et al. proposed a dynamic identity based remote user authentication scheme. This scheme allows the users to choose and change their passwords freely and the server does not maintain any verification table. Das et al. claimed that their scheme is secure against stolen verifier attack, replay attack, forgery attack, dictionary attack, insider attack and identity theft. Unfortunately,...

This paper develops several new techniques of cryptanalyzing MACs based on block ciphers, and is divided into two parts. The first part presents new distinguishers of the MAC construction Alred and its specific instance Alpha-MAC based on AES. For the Alred construction, we first describe a general distinguishing attack which leads to a forgery attack directly with the complexity of the birthda...

In this paper, we provide a security analysis of ELmD: a block cipher based Encrypt-Linear-mix-Decrypt authentication mode. As being one of the second-round CAESAR candidate, it is claimed to provide misuse resistant against forgeries and security against blockwise adaptive adversaries as well as 128-bit security against key recovery attacks. We scrutinize ElmD in such a way that we provide uni...

Technological developments in the field of increasingly advanced computers and networks have caused many organizations to use web applications provide business services. With increasing popularity internet, number cyber-attacks has also increased. To overcome these negative impacts, role network security is very necessary. The Cross Site Request Forgery (CSRF) method a penetration technique aim...

Due to broadcast nature of Wireless Sensor Networks and lack of tamper-resistant hardware, security in sensor networks is one of the major issues. Hence research is being done on many security attacks on wireless sensor networks. Sybil attack is a particular harmful attack. When a node illegitimately claims multiple identities or claims fake id, is called Sybil attack. This paper focuses on var...

A Message Authentication Code (MAC) computes for each (arbitrarily long) message m and key k a short authentication tag which is hard to forge when k is unknown. One of the most popular ways to process m in such a scheme is to use some variant of AES in CBC mode, and to derive the tag from the final ciphertext block. In this paper we analyze the security of several proposals of this type, and s...

In this paper, we present new blind signature schemes based on the factorization problem. They are the first blind signature schemes proved secure relatively to factorization. By security, we mean that no “one-more forgery” is possible even under a parallel attack. In other terms, a user that receives k electronic coins cannot manufacture k + 1. Those security definitions have been introduced b...

Allowing a proxy signer to generate a signature on behalf of an original signer, a proxy signature should satisfy the property of strong unforgeability: anyone except the designated proxy signer cannot create a valid proxy signature on behalf of the original signer. Since proxy signatures, as well as their derivatives, can be used in many applications in reality, such as secure mobile agent, e-...

Shafi Goldwasser∗∗ Silvio Micali∗∗ Ronald L. Rivest ∗∗ Abstract We present a digital signature scheme based on the computational difficulty of integer factorization. The scheme possesses the novel property of being robust against an adaptive chosen-message attack: an adversary who receives signatures for messages of his choice (where each message may be chosen in a way that depends on the signa...