def derive_key_salt(KID, base_key):
  sframe_secret = HKDF-Extract("", base_key)

  sframe_key_label = "SFrame 1.0 Secret key " + KID + cipher_suite
  sframe_key =
    HKDF-Expand(sframe_secret, sframe_key_label, AEAD.Nk)

  sframe_salt_label = "SFrame 1.0 Secret salt " + KID + cipher_suite
  sframe_salt =
    HKDF-Expand(sframe_secret, sframe_salt_label, AEAD.Nn)

  return sframe_key, sframe_salt