Chacha20.hchacha20: def of bend-collections@1.0.0.0
Import: import bend-collections@1.0.0.0/src/crypto/chacha/chacha20.bend as Chacha20
Lines 155-157 of bend-collections@1.0.0.0/src/crypto/chacha/chacha20.bend: https://jend.leeeet.dev/read.txt?path=bend-collections@1.0.0.0/src/crypto/chacha/chacha20.bend&start_line=155&end_line=157

import Base

# HChaCha20(key, nonce): the 32-byte subkey, or None unless 32 and 16 bytes.
def hchacha20(+key_bytes: List<&2, U32>, +nonce_bytes: List<&2, U32>) -> Maybe<&2, List<&2, U32>>:
  when(valid(key_bytes, nonce_bytes, 16n), hchacha20_unchecked(key_bytes, nonce_bytes))

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=Maybe
  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/chacha/chacha20.bend&name=hchacha20_unchecked
  https://jend.leeeet.dev/definition.txt?path=bend-collections@1.0.0.0/src/crypto/chacha/chacha20.bend&name=valid
  https://jend.leeeet.dev/definition.txt?path=bend-collections@1.0.0.0/src/crypto/chacha/chacha20.bend&name=when