Ecdsa.drbg_step: def of bend-collections@1.0.0.0
Import: import bend-collections@1.0.0.0/src/crypto/secp256k1/ecdsa.bend as Ecdsa
Lines 54-57 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=54&end_line=57

import Base

# steps b-g: V = 0x01..., K = 0x00..., then two HMAC rounds over
# V || 0x00 || int2octets(x) || bits2octets(h1) and V || 0x01 || ...
def drbg_step(+k: List<&2, U32>, +v: List<&2, U32>, +tag: U32, +seed: List<&2, U32>) -> Drbg:
  drbg_v(hmac(k, cat(v, tag <> seed)), v)

Uses (6):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=List
  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=Drbg
  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=drbg_v
  https://jend.leeeet.dev/definition.txt?path=bend-collections@1.0.0.0/src/crypto/secp256k1/ecdsa.bend&name=hmac