Issue summary: The generic elliptic-curve scalar multiplication used for
\nECDSA and SM2 signature operations with curves that do not have a dedicated
\nimplementation leaks information about the secret nonce through timing.<\/p>\n
Impact summary: An attacker able to measure signing times may learn
\ninformation about the per-signature secret nonce, which over many signatures
\ncan, via a lattice \/ Hidden Number Problem attack, lead to recovery of the
\nprivate key.<\/p>\n
CWE: CWE-208: Observable Timing Discrepancy<\/p>\n
Description: The generic elliptic-curve scalar multiplication used for
\ncurves that do not have a dedicated constant-time implementation pads the
\nsecret scalar with non-constant-time BIGNUM operations, so the time taken
\ndepends on the value of the secret scalar derived from the ECDSA and SM2 nonce.<\/p>\n
The leak is very small; observing it requires a large number of
\nmeasurements. The effect is largest for curves whose group order lies
\non a machine-word boundary, such as brainpoolP384r1.<\/p>\n
Applications using ECDSA signing over the Brainpool and other generic prime
\ncurves, and SM2 signing on platforms that use the generic implementation,
\nare vulnerable to this issue.<\/p>\n
The NIST curves P-256, P-384 and P-521 use dedicated constant-time
\nimplementations and are not affected.<\/p>\n
FIPS Impact: no
\nThe FIPS modules are not affected: the approved NIST curves used in the FIPS
\nprovider have dedicated constant-time implementations and do not use the
\naffected code path.<\/p>\n","protected":false},"excerpt":{"rendered":"
Issue summary: The generic elliptic-curve scalar multiplication used for
\nECDSA and SM2 signature operations with curves that do not have a dedicated
\nimplementation leaks information about the secret n<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-30623","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/30623","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln"}],"about":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/types\/vuln"}],"wp:attachment":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=30623"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=30623"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=30623"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}