Saturday, 2nd April 2016 - somewhere several meters below surface

"Report, agent."

"Mission 'Capture the bird' was not fully successful, sir. The surprise raid yesterday night encountered unexpected resistance. While the bodyguards were neutralized, the enemy agent managed to swallow a suicide capsule. There will be no chance of interrogation, I'm afraid."

"Not fully successful, you say? I would call that a complete disaster! Vital information is now irretrievably lost to us!"

"Not quite, Sir. We managed to retrieve the personal laptop of the agent. It should hold all the data. It is, naturally, encrypted and locked by a high-security system, though."

"And we have the passcode?"

"Not yet, but we are lucky. It is one of our bugged laptops which has a key-logger installed. So we have all keystrokes right from the first boot-up after buying it, Sir. A copy is stored on your computer."

"Excellent. Nobody has touched the laptop since it was taken?"

"Correct, Sir."

"Well, let's fire it up then."


"Interesting, this is not a standard OS boot. Well, here comes a prompt..."

Logon 1

"What was the last used keyword according to the log?"

"That would be the eight-letter sequence K.Q.Y.E.K.G.I.S, Sir. All capital letters."

"Hmm, lets give it a try then..."




Failed (new)

"Damn it. Would have been too nice, wouldn't it? Maybe we'd better leave this to some experts. Call Mr.S, will you? He should take care from here."

"At once, Sir."

You are Mr.S.
From the information provided, can you tell what security code needs to be entered at this moment now?

The key-logger's complete log can be found below. Unfortunately there has been a bit of data-loss. Corrupted characters are marked as ~.

logged 11/03/2016 10:45:45  cmd
logged 11/03/2016 10:45:52  E:
logged 11/03/2016 10:46:13  c~ SAAETOOS
logged 11/03/2016 10:46:19  s~~up /i:2 /l:8 /dc:1 /fc:1
logged 11/03/2016 12:02:44  shutdown -r
logged 11/03/2016 12:05:02  ~C~GK~~S
logged 11/03/2016 14:15:05  B~~~K~~~
logged 11/03/2016 16:23:32  ~~~~KM~~
logged 12/03/2016 09:02:12  W~~~~QUA
logged 12/03/2016 19:32:09  WC~~~Q~~
logged 12/03/2016 23:02:02  ~~EKO~UA
logged 13/03/2016 00:11:56  ~~EKO~UA
logged 13/03/2016 00:12:32  SWYCEIW~
logged 13/03/2016 11:37:01  SWY~~~WA
logged 13/03/2016 18:03:20  SWYCE~~A
logged 14/03/2016 08:00:04  GISUAGKQ
logged 14/03/2016 15:03:34  GISUAGKQ
logged 14/03/2016 20:20:04  GIUSAGKQ
logged 14/03/2016 20:21:14  WYIKOQCO
logged 14/03/2016 23:41:11  WYIKOQCO
logged 15/03/2016 13:59:51  SUYEGQWC
logged 16/03/2016 09:19:22  IKQUWGUY
logged 17/03/2016 11:23:17  AESYIKOU
logged 19/03/2016 07:30:19  CIOSYGKS
logged 20/03/2016 10:26:10  CEOQWAGO
logged 20/03/2016 16:46:59  CEOQWAGO
logged 20/03/2016 22:00:01  VEOQQAGO
logged 20/03/2016 22:01:13  SUYKSWEI
logged 21/03/2016 07:58:33  OACUAKQW
logged 22/03/2016 07:57:13  YEOUACIO
logged 23/03/2016 08:01:41  SUGQSWCI
logged 23/03/2016 10:04:20  SUGQWSCI
logged 23/03/2016 10:04:30  SUGQSWCI
logged 23/03/2016 10:05:13  YEKOWCGO
logged 23/03/2016 19:49:46  YEKOWCGO
logged 24/03/2016 09:29:33  SGQCEOQU
logged 24/03/2016 23:57:12  SGQCEOQU
logged 25/03/2016 18:15:00  WGUYAESW
logged 26/03/2016 13:10:00  YCWAISAE
logged 29/03/2016 11:00:04  KQEIOUCI
logged 30/03/2016 16:01:30  UYEGQSYI
logged 31/03/2016 19:20:10  KUWCUYAE
logged 01/04/2016 10:01:59  KQYEKGIS
logged 01/04/2016 21:44:00  KQYEKGIS


The puzzle is contained in the key-logger. Story and other text provide additional context which can be helpful. Spelling mistakes are just that: Mistakes (feel free to edit the questions, if they hurt you.)

  • 2
    $\begingroup$ Is the pastebin link ("stored on your computer") deliberately broken? $\endgroup$
    – LeppyR64
    Jun 13, 2016 at 1:27
  • $\begingroup$ @LeppyR64 yes, oversight. Needs to be removed. I first wanted the link and then decided to paste the log here directly and forgot to remove the link. Sorry. $\endgroup$
    – BmyGuest
    Jun 13, 2016 at 5:31
  • 1
    $\begingroup$ It is curious that typing is needed for an "audio and eye-track only" system, isn't it ? $\endgroup$
    – lemon
    Jul 10, 2016 at 6:59
  • 1
    $\begingroup$ Ohh okay, he must have mistyped and corrected in 10 seconds... Thanks :) $\endgroup$
    – shramee
    Jul 13, 2016 at 11:57
  • 1
    $\begingroup$ Minor edit: you should probably change the last used keyword in the flavour text. $\endgroup$
    – yuzuki
    Jul 18, 2016 at 16:50

1 Answer 1


Updated after the question's correction

I think the next valid password is



Here is a possible recovery of most of the missing and mistyped characters: I also added if the password seem to pass or fail (based on the difference between the current and the next timestamp: an attempt is considered fail if there was another attempt right after it)

11/03/2016 10:45:45 cmd
11/03/2016 10:45:52 E:
11/03/2016 10:46:13 cd SAAETOOS
11/03/2016 10:46:19 setup /i:2 /l:8 /dc:1 /fc:1
11/03/2016 12:02:44 shutdown -r
11/03/2016 12:05:02 BC~GKM~S pass
11/03/2016 14:15:05 BC~GKM~S pass
11/03/2016 16:23:32 BC~GKM~S pass
12/03/2016 09:02:12 WCEKOQUA pass
12/03/2016 19:32:09 WCEKOQUA pass
12/03/2016 23:02:02 WCEKOQUA pass
13/03/2016 00:11:56 WCEKOQUA fail
13/03/2016 00:12:32 SWYCEIWA pass
13/03/2016 11:37:01 SWYCEIWA pass
13/03/2016 18:03:20 SWYCEIWA pass
14/03/2016 08:00:04 GISUAGKQ pass
14/03/2016 15:03:34 GISUAGKQ pass
14/03/2016 20:20:04 GIUSAGKQ fail
14/03/2016 20:21:14 WYIKOQCO pass
14/03/2016 23:41:11 WYIKOQCO pass
15/03/2016 13:59:51 SUYEGQWC pass
16/03/2016 09:19:22 IKQUWGUY pass
17/03/2016 11:23:17 AESYIKOU pass
19/03/2016 07:30:19 CIOSYGKS pass
20/03/2016 10:26:10 CEOQWAGO pass
20/03/2016 16:46:59 CEOQWAGO pass
20/03/2016 22:00:01 VEOQWAGO fail
20/03/2016 22:01:13 SUYKSWEI pass
21/03/2016 07:58:33 OACUAKQW pass
22/03/2016 07:57:13 YEOUACIO pass
23/03/2016 08:01:41 SUGQSWCI pass
23/03/2016 10:04:20 SUGQWSCI fail
23/03/2016 10:04:30 SUGQSWCI fail
23/03/2016 10:05:13 YEKOWCGO pass
23/03/2016 19:49:46 YEKOWCGO pass
24/03/2016 09:29:33 SGQCEOQU pass
24/03/2016 23:57:12 SGQCEOQU pass
25/03/2016 18:15:00 WGUYAESW pass
26/03/2016 13:10:00 YCWAISAE pass
29/03/2016 11:00:04 KQEIOUCI pass
30/03/2016 16:01:30 UYEGQSYI pass
31/03/2016 19:20:10 KUWCUYAE pass
01/04/2016 10:01:59 KQYEKGIS pass
01/04/2016 21:44:00 KQYEKGIS pass
02/04/2016 ??:??:?? KQYEKGIS fail (the one that you typed with your boss)

It seems passwords are changing every midnight, and also when there is a failed login. @Mr.Burns added an explanation in his comment how these are related to the setup parameters.

The set of characters being used seem to be odd-numbered letters of alphabet: ACEGIKMOQSUWY (the only exception is the B typed in the second attempt - but that can be a typo). Maybe this relates to parameter 'i=2'?

So it seems the list of correct keys in order is the following:
[missing in case of dc stands for day count and not for day change]
[missing in case of dc stands for day count and not for day change]
[missing in case of dc stands for day count and not for day change]
[the one to guess]

If we convert the first letters to numbers according to where they are in the alphabet, the first password turns into: 2, 3, ?, 7, 11, 13, ?, 19.
This pattern wasn't too hard to recognize: 2, 3, 5, 7, 11, 13, 17, 19 are the first prime numbers. The next password confirmed my natural suspicion, that the keywords are the list of prime numbers modulo 26, converted to letters.

After that it was easy to check if dc stands for day change or day count:
AESYIKOU stands for 313, 317, 331, 337, 347, 349, 353, 359, and
CIOSYGKS perfectly matches 367, 373, 379, 383, 389, 397, 401, 409,
so it seems there isn't an automatic password update after a day without login, dc stands for day change.
(And by the way, i:2 is probably for initialization, primes are listed from 2)

So then the question reduced to finding primes indexed 201 to 208.
Those are 1229, 1231, 1237, 1249, 1259, 1277, 1279, 1283.
Modulo 26: 7, 9, 15, 1, 11, 3, 5, 9.
Transformed to letters: G, I, O, A, K, C, E, I.

  • 2
    $\begingroup$ Ok so my current guess for the set up part is, /l:8 = Character length of the password, /fc:1 = failure count (might be wrong this), how many times you can enter a password before it changes, IE you fail once you need a new password, /dc:1 = day count (again not sure) but each new day the password changes. /i:2 I dont know yet, feel free to update you answer with this if you like $\endgroup$
    – Mr.Burns
    Jul 18, 2016 at 10:33
  • 1
    $\begingroup$ Update to my comment (Just for clarification), /fc:1 = failure count, how many attempts can be made before password needs to reset, so if you fail once on this PC you need a new password. /dc:1 = day count, this is how long the password will last (not including /fc), so on this PC the password will last for 1 day. /l:8 = Length, the minimum and miximum character length of the password (this doesnt seem to include numbers) $\endgroup$
    – Mr.Burns
    Jul 18, 2016 at 10:50
  • 2
    $\begingroup$ Another clue/hint might be the duplicate appearance of 'SWYCEIWA' on both the 13th and the 14th. Given the current fail interpretation, both would have resulted from a password change triggered by a failed entry. $\endgroup$ Jul 18, 2016 at 12:33
  • 1
    $\begingroup$ Yes, @HenrikOpel, that's an observation I myself had too, and is a little bit troubling - but also helping. It means, that the system has 'memory', meaning the next password isn't generated from the previous one - in that case, the same word would be followed by identical passwords. $\endgroup$
    – elias
    Jul 18, 2016 at 12:51
  • 1
    $\begingroup$ @lemon, I don't see that hypothesis supported by the timestamps. What can be the reason to execute the test sequence passwords with many hour pause between them? $\endgroup$
    – elias
    Jul 18, 2016 at 15:21

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