cid 57088419de0eac951ed2d8f525780b00c8a05bcfdd5f0a61b396f0630dc8ef89 · original · open access · via openalex
Title: "Make Sure DSA Signing Exponentiations Really are Constant-Time" Authors: Cesar Pereida García; Billy Bob Brumley; Yuval Yarom Venue: ACM SIGSAC Conference on Computer and Communications Security (CCS) Year: 2016 Canonical: doi:10.1145/2976749.2978420 URL: https://doi.org/10.1145/2976749.2978420 Collector: openalex OA: true ABSTRACT TLS and SSH are two of the most commonly used protocols for securing Internet traffic. Many of the implementations of these protocols rely on the cryptographic primitives provided in the OpenSSL library. In this work we disclose a vulnerability in OpenSSL, affecting all versions and forks (e.g. LibreSSL and BoringSSL) since roughly October 2005, which renders the implementation of the DSA signature scheme vulnerable to cache-based side-channel attacks. Exploiting the software defect, we demonstrate the first published cache-based key-recovery attack on these protocols: 260 SSH-2 handshakes to extract a 1024/160-bit DSA host key from an OpenSSH server, and 580 TLS 1.2 handshakes to extract a 2048/256-bit DSA key from an stunnel server.