X25519.rung: 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 81-86 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=81&end_line=86

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

# swap ^= k_t; cswap; the step; swap = k_t
def rung(+c24: List<&2, U32>, +x1: List<&2, U32>, st: St, +kt: U32) -> St:
  match st:
    case St{+x2, +z2, +x3, +z3, swap}:
      +sw = U32.xor(swap, kt)
      step(c24, x1, F.select(sw, x2, x3), F.select(sw, z2, z3), F.select(sw, x3, x2), F.select(sw, z3, z2), kt)

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=Base/base.bend&name=U32.xor
  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/x25519.bend&name=St
  https://jend.leeeet.dev/definition.txt?path=bend-collections-laws-crypto@1.0.0.0/src/crypto/curve25519/x25519.bend&name=step