International Association for Cryptologic Research

International Association
for Cryptologic Research

CryptoDB

Virginie Lallemand

Affiliation: CNRS, France

Publications

Year
Venue
Title
2019
EUROCRYPT
bison Instantiating the Whitened Swap-Or-Not Construction 📺
We give the first practical instance – bison – of the Whitened Swap-Or-Not construction. After clarifying inherent limitations of the construction, we point out that this way of building block ciphers allows easy and very strong arguments against differential attacks.
2019
ASIACRYPT
Forkcipher: A New Primitive for Authenticated Encryption of Very Short Messages
Highly efficient encryption and authentication of short messages is an essential requirement for enabling security in constrained scenarios such as the CAN FD in automotive systems (max. message size 64 bytes), massive IoT, critical communication domains of 5G, and Narrowband IoT, to mention a few. In addition, one of the NIST lightweight cryptography project requirements is that AEAD schemes shall be “optimized to be efficient for short messages (e.g., as short as 8 bytes)”.In this work we introduce and formalize a novel primitive in symmetric cryptography called forkcipher. A forkcipher is a keyed primitive expanding a fixed-lenght input to a fixed-length output. We define its security as indistinguishability under a chosen ciphertext attack (for n-bit inputs to 2n-bit outputs). We give a generic construction validation via the new iterate-fork-iterate design paradigm.We then propose $$ {\mathsf {ForkSkinny}} $$ as a concrete forkcipher instance with a public tweak and based on SKINNY: a tweakable lightweight cipher following the TWEAKEY framework. We conduct extensive cryptanalysis of $$ {\mathsf {ForkSkinny}} $$ against classical and structure-specific attacks.We demonstrate the applicability of forkciphers by designing three new provably-secure nonce-based AEAD modes which offer performance and security tradeoffs and are optimized for efficiency of very short messages. Considering a reference block size of 16 bytes, and ignoring possible hardware optimizations, our new AEAD schemes beat the best SKINNY-based AEAD modes. More generally, we show forkciphers are suited for lightweight applications dealing with predominantly short messages, while at the same time allowing handling arbitrary messages sizes.Furthermore, our hardware implementation results show that when we exploit the inherent parallelism of $$ {\mathsf {ForkSkinny}} $$ we achieve the best performance when directly compared with the most efficient mode instantiated with SKINNY.
2018
JOFC
2018
CRYPTO
Rasta: A Cipher with Low ANDdepth and Few ANDs per Bit 📺
Recent developments in multi party computation (MPC) and fully homomorphic encryption (FHE) promoted the design and analysis of symmetric cryptographic schemes that minimize multiplications in one way or another. In this paper, we propose with Rastaa design strategy for symmetric encryption that has ANDdepth d and at the same time only needs d ANDs per encrypted bit. Even for very low values of d between 2 and 6 we can give strong evidence that attacks may not exist. This contributes to a better understanding of the limits of what concrete symmetric-key constructions can theoretically achieve with respect to AND-related metrics, and is to the best of our knowledge the first attempt that minimizes both metrics simultaneously. Furthermore, we can give evidence that for choices of d between 4 and 6 the resulting implementation properties may well be competitive by testing our construction in the use-case of removing the large ciphertext-expansion when using the BGV scheme.
2016
CRYPTO
2015
EPRINT
2015
EPRINT
2015
EUROCRYPT
2015
CRYPTO
2014
EPRINT
2014
EPRINT
2014
FSE

Program Committees

FSE 2020
FSE 2019
Asiacrypt 2019
FSE 2018
Asiacrypt 2018