Ecdsa.recover_ok: def of bend-collections-laws-crypto@1.0.0.0
Import: import bend-collections-laws-crypto@1.0.0.0/src/crypto/secp256k1/ecdsa.bend as Ecdsa
Lines 250-258 of bend-collections-laws-crypto@1.0.0.0/src/crypto/secp256k1/ecdsa.bend: https://jend.leeeet.dev/read.txt?path=bend-collections-laws-crypto@1.0.0.0/src/crypto/secp256k1/ecdsa.bend&start_line=250&end_line=258

import Base
import bend-collections-laws-crypto@1.0.0.0/src/crypto/secp256k1/field.bend as F
import bend-collections-laws-crypto@1.0.0.0/src/crypto/secp256k1/scalar.bend as S

# x = r + j n with j = id / 2. For j = 1, r + n must be below p: then
# (r + n) mod p = r + n >= n, while a wrapped r + n - p is below r < n
def recover_ok(+z: List<&2, Nat>, +r: List<&2, Nat>, +s: List<&2, Nat>, +id: Nat, ok: Bool) -> Maybe<&2, List<&2, U32>>:
  match ok:
    case True{}:
      +j = Nat.div(id, 2n)
      +x1 = rn_fe(r)
      recover_x(z, r, s, id, F.select(j, x1, r), Bool.or(Nat.is_eq(j, 0n), Bool.not(S.lt_n(x1))))
    case False{}: None{}

Uses (13):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Bool
  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.div
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Nat.is_eq
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=U32
  https://jend.leeeet.dev/definition.txt?path=bend-collections-laws-crypto@1.0.0.0/src/crypto/secp256k1/ecdsa.bend&name=recover_x
  https://jend.leeeet.dev/definition.txt?path=bend-collections-laws-crypto@1.0.0.0/src/crypto/secp256k1/ecdsa.bend&name=rn_fe
  https://jend.leeeet.dev/definition.txt?path=bend-collections-laws-crypto@1.0.0.0/src/crypto/secp256k1/field.bend&name=select
  https://jend.leeeet.dev/definition.txt?path=bend-collections-laws-crypto@1.0.0.0/src/crypto/secp256k1/scalar.bend&name=lt_n