Upstream information
Description
Generating the ECDSA nonce k samples a random number r and thentruncates this randomness with a modular reduction mod n where n is the
order of the elliptic curve. Meaning k = r mod n. The division used
during the reduction estimates a factor q_e by dividing the upper two
digits (a digit having e.g. a size of 8 byte) of r by the upper digit of
n and then decrements q_e in a loop until it has the correct size.
Observing the number of times q_e is decremented through a control-flow
revealing side-channel reveals a bias in the most significant bits of
k. Depending on the curve this is either a negligible bias or a
significant bias large enough to reconstruct k with lattice reduction
methods. For SECP160R1, e.g., we find a bias of 15 bits.
SUSE information
Overall state of this security issue: Does not affect SUSE products
This issue is currently not rated by SUSE as it is not affecting the SUSE Enterprise products.
SUSE Bugzilla entry: 1229876 [NEW] No SUSE Security Announcements cross referenced.SUSE Timeline for this CVE
CVE page created: Tue Aug 27 22:00:34 2024CVE page last modified: Wed Aug 28 20:48:28 2024