Firewalls typically filter network traffic at several different layers. At application layer, filtering is based on various security relevant information encapsulated into protocol messages. The major obstacle for efficient verification of authenticity of messages at application layer is the difficulty of verifying digital signatures without disclosure of content protected by encryption. This i...

Digital signatures whose security does not rely on any unproven computational assumption have recently received considerable attention. While these unconditionally secure digital signatures provide a foundation for long term integrity and non-repudiation of data, currently known schemes generally require a far greater amount of memory space for the storage of users’ secret information than a tr...

The authenticated encryption scheme allows one signer to generate an authenticated cipher-text so that no one except the designated verifier can recover the message and verify the message. In a (t, n) threshold authenticated encryption scheme, any t or more signers can generate an authenticated encryption for a message and send it to the designated verifier. Compared with the conventional encry...

In 1997, two new schemes for authenticated encryption, called signcryption, have been proposed by Zheng. In this paper we point out a serious problem with these schemes. In fact, the way to gain nonrepudiation violates the confidentiality. Moreover, we compare the schemes to previously known authenticated encryption schemes, which were not mentioned by Zheng. Finally we outline a solution that ...

VANET provide facility for the vehicles on roads to communicate for driving safety. The basic idea is to allow arbitrary vehicles to broadcast ad hoc messages to other vehicles. However, this raises the issue of security and privacy. Here, we have described various existing solutions/protocols that are used in order to satisfy the security and privacy requirement of the vehicular ad hoc network...

Cryptography is the study of mathematical techniques for all aspects of information security. Cryptanalysis is the complementary science concerned with the methods to defeat these techniques. Cryptology is the study of cryptography and cryptanalysis. The security of information encompasses the following aspects: • confidentiality or privacy, • data integrity, • authentication, • nonrepudiation....

Many P2P applications require security services such as privacy, anonymity, authentication, and non-repudiation. Such services could be provided through a hierarchical Public Key Infrastructure. However, P2P networks are usually Internet-scale distributed systems comprised of nodes with undetermined trust level, thus making hierarchical solutions unrealistic. In this paper, we propose Chord-PKI...

When large Multi Agent Systems operate over open platforms such as the Internet, there is the possibility that some agents will endeavor to disrupt the MAS with the aim of achieving their own agendas at the cost of the others. For the protection of the agents in it's domain, each society of agents should make available certain services that allow agents to detect and avoid such attempts by mali...

attitude is dangerous: crypto provides the foundation for any real attempt at security or privacy. Without it, we couldn’t build truly secure solutions for the challenges of information confidentiality and integrity or individual user authentication and authorization; we also wouldn’t be able to deal with more complicated concepts such as signing digital documents or enabling nonrepudiation for...