Listing OneTime bugs here until set up a real bug tracker.

* onetime -d -p PAD INPUT -o OUTPUT(=?) failed on option parsing?

  Test this usage scenario.

* Off-by-one-error when when adding the next encrypted length each time?

  Try encrypting long-msg multiple times, watch the used range climb
  by "length(long-msg) - 1" each time.

* We're not compressing plaintext, we're compressing crypttext.

  So usage() is wrong, but also, that means we're not saving pad as we
  could be.

* Failed decryption should create no output file, not create 0-byte file.