Various cryptographic puzzle schemes are proposed as a defense mechanism against
denial of service attack. But, all these puzzle schemes face a dilemma when there is a large …

By a computational puzzle we mean a mildly difficult computational problem that requires
resources (processor cycles, memory, or both) to solve. Puzzles have found a variety of uses …

Cryptographic puzzles provide an elegant solution in combating denial of services attacks.
In this paper we introduce the concept of chained cryptographic puzzle. We define two kinds …

In this paper, we present Productive Puzzles, a novel puzzle mechanism for defending
against Distributed Denial of Service (DDoS) attacks. Productive puzzles aim to use tasks …

Denial of Service (DoS) attacks aiming to exhaust the resources of a server by
overwhelming it with bogus requests have become a serious threat. Especially protocols that …

We explore new techniques for the use of cryptographic puzzles as a countermeasure to
Denial-of-Service (DoS) attacks. We propose simple new techniques that permit the out …

Denial-of-service (DoS) and distributed DoS (DDoS) are among the major threats to cyber-
security, and client puzzle, which demands a client to perform computationally expensive …

Denial of Service (DoS) attacks aiming to exhaust the resources of a server by
overwhelming it with bogus requests have become a serious threat. Especially protocols that …

Although client puzzles represent a promising approach to defend against certain classes of
denial-of-service attacks, several questions stand in the way of their deployment in practice …

CPU bound client puzzles have been suggested as a defense mechanism against
connection depletion attacks. However, the wide disparity in CPU speeds prevents such …