Whether a JWK may be used to verify signatures (RFC 7517 4.2/4.3): a key
declaring use must declare use=="sig", and a key declaring key_ops must
include "verify". Keys that declare neither are usable (the members are
optional). Keys declaring an incompatible use/op are excluded as candidates.
Whether a JWK may be used to verify signatures (RFC 7517 4.2/4.3): a key declaring use must declare use=="sig", and a key declaring key_ops must include "verify". Keys that declare neither are usable (the members are optional). Keys declaring an incompatible use/op are excluded as candidates.