Dodis et al proposed a key-insulated signature scheme in 2003. In the scheme, total lifetime of a certificate is divided to time periods and different secret keys are used for each time period. The master secret key is stored in the physically secure device and is not used for signing directly. The different secret keys are used for signature in each time period and they are refreshed by a comp...

Efficient key establishment is an important problem for secure group communications. The communication and storage complexity of group key establishment problem has been studied extensively. In this paper, we propose a new group key establishment protocol whose computation complexity is significantly reduced. Instead of using classic secret sharing, the protocol only employs a linear secret sha...

The Diffie-Hellman key agreement protocol, is a procedure that allows establishing a shared secret over an insecure connection and was developed by Whitfield Diffie and Martin Hellman in 1976, . This procedure is, often slightly modified, still used today by several applications. Before going into more detail on these applications, let’s have a look at the basic key-exchange method between two ...

This is the second part of a two-part paper on information-theoretically secure secret key agreement. This paper focuses on the secret key rate problem under the channel model. In the channel model, a set of two or more terminals wish to create a shared secret key that is information-theoretically secure from an eavesdropper. The first terminal can choose a sequence of inputs to a discrete memo...

We propose a cryptosystem that has an inherent key escrow mechanism. This leads us to propose a session based public verifiable key escrow system that greatly improves the amount of key material the escrow servers has to keep in order to decrypt an encryption. In our scheme the servers will only have a single secret sharing, as opposed to a single key from every escrowed player. This is done wh...

We present two new schemes that, in the absence of a centralized support, allow a pair of nodes of a mobile ad hoc network to compute a shared key without communicating. Such a service is important to secure routing protocols [1–3]. The schemes are built using the well-known technique of threshold secret sharing and are secure against a collusion of up to a certain number of nodes. We evaluate ...

The current work proposes a new scheme for the replication of authentication services in Kuperee based on a public key cryptosystem, in response to the two main shortcomings of the traditional single server solutions, namely those of low availability and high security risks. The work represents further developments in the Kuperee authentication system. The Kuperee server is presented in its bas...

Wired equivalent privacy encryption of IEEE 802.11 standard is based on the RC4 stream cipher, but the weakness in its Initialization Vector (IV) derivation causes the Key Scheduling Algorithm (KSA) of RC4 to leak out the information about the secret key. It is shared among the particular participants in the Wireless LAN (WLAN). Housley et al. proposed an Alternate Temporal Key Hash (ATKH) to s...

This paper presents a cost-effective private-key cryptosystem for color images. The scheme allows for secret sharing of the color image by generating two color shares with dimensions identical to those of the original. Encryption is performed via simple binary operations realized at the image bit-levels altering both the spectral correlation among the RGB color components and the spatial correl...

Ad-hoc networks — and in particular wireless mobile ad-hoc networks — have unique characteristics and constraints that make traditional cryptographic mechanisms and assumptions inappropriate. In particular, it may not be warranted to assume pre-existing shared secrets between members of the network or the presence of a common PKI. Thus, the issue of key distribution in ad-hoc networks represent...