Ecdsa.sign_loop: def of bend-collections@1.0.0.0
Import: import bend-collections@1.0.0.0/src/crypto/secp256k1/ecdsa.bend as Ecdsa
Lines 109-122 of bend-collections@1.0.0.0/src/crypto/secp256k1/ecdsa.bend: https://jend.leeeet.dev/read.txt?path=bend-collections@1.0.0.0/src/crypto/secp256k1/ecdsa.bend&start_line=109&end_line=122

import Base

# step h: the candidate V; a k outside [1, n - 1], or one giving r = 0 or
# s = 0 (SEC 1 section 4.1.3 steps 3 and 6), is replaced by the next
# candidate: K = HMAC_K(V || 0x00), V = HMAC_K(V), V = HMAC_K(V). The loop
# stops after `fuel` candidates (the chance that even 2 are needed is below
# 2^-127).
def sign_loop(fuel: Nat, +z: List<&2, Nat>, +d: List<&2, Nat>, +k: List<&2, U32>, +v: List<&2, U32>, att: Attempt) -> Maybe<&2, Signature>:
  match fuel att:
    case 0n ARetry{}: None{}
    case 0n ADone{sig}: Some{sig}
    case 1n+f ARetry{}:
      +k2 = hmac(k, cat(v, [0]))
      +v3 = hmac(k2, hmac(k2, v))
      sign_loop(f, z, d, k2, v3, attempt(z, d, v3))
    case 1n+f ADone{sig}: Some{sig}

Uses (9):
  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=U32
  https://jend.leeeet.dev/definition.txt?path=bend-collections@1.0.0.0/src/crypto/secp256k1/ecdsa.bend&name=Attempt
  https://jend.leeeet.dev/definition.txt?path=bend-collections@1.0.0.0/src/crypto/secp256k1/ecdsa.bend&name=Signature
  https://jend.leeeet.dev/definition.txt?path=bend-collections@1.0.0.0/src/crypto/secp256k1/ecdsa.bend&name=attempt
  https://jend.leeeet.dev/definition.txt?path=bend-collections@1.0.0.0/src/crypto/secp256k1/ecdsa.bend&name=cat
  https://jend.leeeet.dev/definition.txt?path=bend-collections@1.0.0.0/src/crypto/secp256k1/ecdsa.bend&name=hmac