WS-2023-0284

Date: August 9, 2023

Blst versions v0.3.0 through 0.3.10 failed to perform a signature group-check if the call to SigValidate in the Go bindings was complemented with a check for infinity. Formally speaking, infinity, or the identity element of the elliptic curve group, is a member of the group, and the group-check should allow it. An initial review of blst users on GitHub did not uncover any use of this function with the complementary infinity check. This optional check was added as a convenience feature because despite infinity being a legitimate member of the group, individual signatures should never be infinite (as it is equivalent to having zero for the secret key), and observing one should raise a flag.

Language: Go