X25519.finish: def of bend-collections-laws-crypto@1.0.0.0
Import: import bend-collections-laws-crypto@1.0.0.0/src/crypto/curve25519/x25519.bend as X25519
Lines 117-121 of bend-collections-laws-crypto@1.0.0.0/src/crypto/curve25519/x25519.bend: https://jend.leeeet.dev/read.txt?path=bend-collections-laws-crypto@1.0.0.0/src/crypto/curve25519/x25519.bend&start_line=117&end_line=121

import Base
import bend-collections-laws-crypto@1.0.0.0/src/crypto/curve25519/field.bend as F

# the final cswap, then x2 * z2^(p - 2), encoded
def finish(st: St) -> List<&2, U32>:
  match st:
    case St{+x2, +z2, +x3, +z3, +swap}:
      F.to_bytes(F.mul(F.select(swap, x2, x3), F.inv(F.select(swap, z2, z3))))

Uses (7):
  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-laws-crypto@1.0.0.0/src/crypto/curve25519/field.bend&name=inv
  https://jend.leeeet.dev/definition.txt?path=bend-collections-laws-crypto@1.0.0.0/src/crypto/curve25519/field.bend&name=mul
  https://jend.leeeet.dev/definition.txt?path=bend-collections-laws-crypto@1.0.0.0/src/crypto/curve25519/field.bend&name=select
  https://jend.leeeet.dev/definition.txt?path=bend-collections-laws-crypto@1.0.0.0/src/crypto/curve25519/field.bend&name=to_bytes
  https://jend.leeeet.dev/definition.txt?path=bend-collections-laws-crypto@1.0.0.0/src/crypto/curve25519/x25519.bend&name=St