Biblio

This paper analyzes the authenticated encryption algorithm ACORN, a candidate in the CAESAR cryptographic competition. We identify weaknesses in the state update function of ACORN which result in collisions in the internal state of ACORN. This paper shows that for a given set of key and initialization vector values we can construct two distinct input messages which result in a collision in the ACORN internal state. Using a standard PC the collision can be found almost instantly when the secret key is known. This flaw can be used by a message sender to create a forged message which will be accepted as legitimate.

π-Cipher is one of the twenty-nine candidates in the second round of the CAESAR competition for authenticated ciphers. π-Cipher uses a parallel sponge construction, based upon an ARX permutation. This work shows several state recovery attacks, on up to three rounds. These attacks use known values in the function's bitrate, combined with values found through exhaustive search, to retrieve the remaining values in the internal state. These attacks can break one round, for any variant of π-Cipher, in negligible time. They can also break two or three rounds much faster than exhaustive search on the key, for some variants. However, these attacks only work against version 1 of π-Cipher, due to the differences in the padding function for version 2.0. To fill this gap, this work also includes a one round attack against version 2.0, building upon the distinguisher present in the π-Cipher submission document.

In response to the critical challenges of the current Internet architecture and its protocols, a set of so-called clean slate designs has been proposed. Common among them is an addressing scheme that separates location and identity with self-certifying, flat and non-aggregatable address components. Each component is long, reaching a few kilobits, and would consume an amount of fast memory in data plane devices (e.g., routers) that is far beyond existing capacities. To address this challenge, we present Caesar, a high-speed and length-agnostic forwarding engine for future border routers, performing most of the lookups within three fast memory accesses. To compress forwarding states, Caesar constructs scalable and reliable Bloom filters in Ternary Content Addressable Memory (TCAM). To guarantee correctness, Caesar detects false positives at high speed and develops a blacklisting approach to handling them. In addition, we optimize our design by introducing a hashing scheme that reduces the number of hash computations from k to log(k) per lookup based on hash coding theory. We handle routing updates while keeping filters highly utilized in address removals. We perform extensive analysis and simulations using real traffic and routing traces to demonstrate the benefits of our design. Our evaluation shows that Caesar is more energy-efficient and less expensive (in terms of total cost) compared to optimized IPv6 TCAM-based solutions by up to 67% and 43% respectively. In addition, the total cost of our design is approximately the same for various address lengths.