static PKIKeyPair keyPairForProgram() {
  lock programLock();
  File f = programFile("key-pair.txt");
  pcall {
    LS l = tlft(loadTextFile(f));
    if (l(l) == 2) ret PKIKeyPair(first(l), second(l));
  }
  PKIKeyPair pair = pki_newKeyPair();
  saveTextFile(f, lines(pair.publicKey, pair.privateKey));
  ret pair;
}