Chacha20.chacha20_block: def of bend-collections@1.0.0.0
Import: import bend-collections@1.0.0.0/src/crypto/chacha/chacha20.bend as Chacha20
Lines 145-148 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=145&end_line=148

import Base

# chacha20_block(key, counter, nonce): 64 bytes, or None unless the key has 32
# bytes and the nonce 12.
def chacha20_block(+key_bytes: List<&2, U32>, counter: U32, +nonce_bytes: List<&2, U32>) -> Maybe<&2, List<&2, U32>>:
  when(valid(key_bytes, nonce_bytes, 12n), block_rounds(10n, key_bytes, counter, 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=block_rounds
  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