Ecdsa.verify_q: def of bend-collections@1.0.0.0
Import: import bend-collections@1.0.0.0/spec/crypto/secp256k1/ecdsa.bend as Ecdsa
Lines 178-185 of bend-collections@1.0.0.0/spec/crypto/secp256k1/ecdsa.bend: https://jend.leeeet.dev/read.txt?path=bend-collections@1.0.0.0/spec/crypto/secp256k1/ecdsa.bend&start_line=178&end_line=185

import Base
import bend-collections@1.0.0.0/spec/crypto/secp256k1/curve.bend as CV

# r and s in [1, n - 1]; strict verification also rejects s > n / 2
def verify_q(+one: Nat, +h: List<&2, U32>, +sig: List<&2, U32>, strict: Bool, mq: Maybe<&2, CV.SPoint>) -> Bool:
  match mq:
    case None{}: False{}
    case Some{+q}:
      +r = CV.os2ip(CV.first(32n, sig))
      +s = CV.os2ip(CV.after(32n, sig))
      verify_ok(one, q, hash_scalar(one, h), r, s, Bool.and(Bool.and(scalar_ok(one, r), scalar_ok(one, s)), Bool.or(Bool.not(strict), Bool.not(Nat.is_lt(n(one), Nat.double(s))))))

Uses (18):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Bool
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Bool.and
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Bool.not
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Bool.or
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=List
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Maybe
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Nat
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Nat.double
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Nat.is_lt
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=U32
  https://jend.leeeet.dev/definition.txt?path=bend-collections@1.0.0.0/spec/crypto/secp256k1/curve.bend&name=SPoint
  https://jend.leeeet.dev/definition.txt?path=bend-collections@1.0.0.0/spec/crypto/secp256k1/curve.bend&name=after
  https://jend.leeeet.dev/definition.txt?path=bend-collections@1.0.0.0/spec/crypto/secp256k1/curve.bend&name=first
  https://jend.leeeet.dev/definition.txt?path=bend-collections@1.0.0.0/spec/crypto/secp256k1/curve.bend&name=os2ip
  https://jend.leeeet.dev/definition.txt?path=bend-collections@1.0.0.0/spec/crypto/secp256k1/ecdsa.bend&name=hash_scalar
  https://jend.leeeet.dev/definition.txt?path=bend-collections@1.0.0.0/spec/crypto/secp256k1/ecdsa.bend&name=n
  https://jend.leeeet.dev/definition.txt?path=bend-collections@1.0.0.0/spec/crypto/secp256k1/ecdsa.bend&name=scalar_ok
  https://jend.leeeet.dev/definition.txt?path=bend-collections@1.0.0.0/spec/crypto/secp256k1/ecdsa.bend&name=verify_ok