Cryptanalysis of Full SCARF

Antonio Flórez-Gutiérrez; Eran Lambooij; Gaëtan Leurent; Håvard Raddum; Tyge Tiessen; Michiel Verbauwhede

Paper 2025/315

Cryptanalysis of Full SCARF

Antonio Flórez-Gutiérrez

, NTT Social Informatics Laboratories, NTT Corporation, Japan

Eran Lambooij, Department of Mathematics, Bar-Ilan University, Ramat Gan, Israel

Gaëtan Leurent

, Inria, Paris, France

Håvard Raddum

, Simula UiB, Bergen, Norway

Tyge Tiessen

, Technical University of Denmark, Denmark

Michiel Verbauwhede

, COSIC, KU Leuven, Leuven, Belgium

Abstract

SCARF is a tweakable block cipher dedicated to cache address randomization, proposed at the USENIX Security conference. It has a 10-bit block, 48-bit tweak, and 240-bit key. SCARF is aggressively optimized to meet the harsh latency constraints of cache address randomization, and uses a dedicated model for its security claim. The full version of SCARF has 8 rounds, and its designers claim security up to queries and computations. In this work we present a distinguisher against 6-round SCARF under the collision model with time and query complexity , and a key-recovery attack against the full 8-round SCARF under the encryption-decryption model with queries and time . As part of the attack, we present a novel method to compute the minimal number of right pairs following a differential characteristic when the input pairs are restricted to a subspace of the domain of the primitive.

Note: This is an expanded version of the corresponding Eurocrypt paper.

Metadata

Available format(s): PDF
Category: Secret-key cryptography
Publication info: A minor revision of an IACR publication in EUROCRYPT 2025
Keywords: SCARF tweakable block cipher cryptanalysis
Contact author(s): antonio florez @ ntt com
eran lambooij @ biu ac il
gaetan leurent @ inria fr
haavardr @ simula no
tyti @ dtu dk
michiel verbauwhede @ esat kuleuven be
History: 2025-02-21: approved; 2025-02-21: received; See all versions
Short URL: https://ia.cr/2025/315
License: CC BY

BibTeX

@misc{cryptoeprint:2025/315,
      author = {Antonio Flórez-Gutiérrez and Eran Lambooij and Gaëtan Leurent and Håvard Raddum and Tyge Tiessen and Michiel Verbauwhede},
      title = {Cryptanalysis of Full {SCARF}},
      howpublished = {Cryptology {ePrint} Archive, Paper 2025/315},
      year = {2025},
      url = {https://eprint.iacr.org/2025/315}
}