Hash-based Signature Scheme Research Articles

Shorter hash-based signatures

We describe an efficient hash-based signature scheme that yields shorter signatures than the state of the art. Signing and verification are faster as well, and the overall scheme is suitable for constrained platforms typical of the Internet of Things. We describe an efficient implementation of our improved scheme and show memory, time, and energy consumption benchmarks over a real device, i.e. the ATmega128l 8-bit AVR microcontroller embedded in MICAz, a typical sensor node used in wireless sensor networks.

On Pseudo-Random Oracles

ABSTRACT Many cryptographic systems which involve hash functions have proof of their security in a so called random oracle model. Behavior of hash functions used in such cryptographic systems should be as close as possible to the behavior of a random function. There are several properties of hash functions dealing with a random behavior. A hash function is pseudo-random oracle if it is indifferentiable from a random oracle. However, it is well known that hash functions based on the popular Merkle-Damg˚ard domain extension transform do not satisfy the pseudo-random oracle property. On the other hand no attack is known for many concrete applications utilizing Merkle-Damg˚ard hash functions. Hence, a weakened notion called public-use pseudo random oracle was introduced. The property can be met by the Merkle-Damg˚ard construction and is sufficient for several important applications. A hash function is public use pseudo-random oracle if it is indifferentiable from a random oracle with public messages (i.e., all messages hashed so far are available to all parties). This is the case of most hash based signature schemes. In this paper we analyze relationship between the property pseudo-random oracle and its variant public image pseudo-random oracle. Roughly, a hash function is public image pseudo-random oracle if it is indifferentiable from a random oracle with public images (i.e., all images of messages hashed so far are available to all parties, messages are kept secret). We prove that the properties are equivalent.

A modeling framework of content pollution in Peer-to-Peer video streaming systems

Peer-to-Peer (P2P) live video streaming systems are known to suffer from intermediate attacks due to its inherent vulnerabilities. The content pollution is one of the common attacks that have received little attention in P2P live streaming systems. In this paper, we propose a modeling framework of content pollution in P2P live streaming systems. This model considers both unstructured and structured overlays, and captures the key factors including churns, user interactions, multiple attackers and defensive techniques. The models are verified with simulations and implemented in a real working system, Anysee. We analyze content pollution and its effect in live streaming system. We show that: (1) the impact from content pollution can exponentially increase, similar to the random scanning worms, leading to playback interruption and unnecessary bandwidth consumption; (2) content pollution is influenced by peer cooperation, peer degree and bandwidth in unstructured overlays, and topology breadth in structured ones; (3) the structured overlay is more resilient to content pollution; (4) a hybrid overlay result in better reliability and pollution resistance; (5) hash-based chunk signature scheme is most promising against content pollution.