SignDerived(d, label, message):
  /* Key expansion */
  dh := SHA-512(d)
  /* EdDSA clamping */
  a := dh[0..31]
  a[0] := a[0] & 248
  a[31] := a[31] & 127
  a[31] := a[31] | 64
  /* Calculate zkey corresponding to d */
  zkey := a * G

  /* Calculate blinding factor */
  PRK_h := HKDF-Extract("key-derivation", zkey)
  h := HKDF-Expand(PRK_h, label || "gns", 512 / 8)
  /* Ensure that h == h mod L */
  h := h mod L

  d' := (h * a) mod L
  nonce := SHA-256(dh[32..63] || h)
  r := SHA-512(nonce || message)
  R := r * G
  S := r + SHA-512(R || zkey' || message) * d' mod L
  return (R,S)