This is part of The Twenty Doors series.
The previous one is The Twenty Doors (ROOM 4)
The next one is The Twenty Doors! (ROOM 6)

You go through into room five. There is a standard keyboard, and, of course, the paper:

Pidi ou nto seeob r thf ruusnei yeivboae f t .eoqo vrs rwlmdthuih rrlweyoei

You can just make out the carving into the wall. Kwei sdoa c etfcbeqs zvcd, ukl ghcds'u lwkweivkxu hd. E uvhdcdf hkoza-kqwi ifsdt!                                                                                                                                                               There are eight-million, four-hundred and ninety-six thousand, three-hundred and twenty-one pies.

What is the word that you should enter?


The wall carving is actually a hint to the paper. You don't necessarily need to solve the wall carving in order to know the puzzle. If you do want to, however, know that the bit about a large number of pies is only important to decrypting that unimportant cipher. So, spend most of your time on the paper, for decrypting that will give you a word.

HINT 2: This is what is written on the wall carving, don't read if you want to work it out yourself.

Much like a skipping rope, the paper's cipher be. I skipped fifty-four times!

The next door will be added when this door is solved!

  • 3
    $\begingroup$ Standard keyboard, so a keyboard related puzzle. And even though I like pie, that many pies would surely give you a stomachache. $\endgroup$ – mmking Jul 5 '15 at 14:37
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    $\begingroup$ I think it's time for a hint. $\endgroup$ – CodeNewbie Jul 7 '15 at 8:00
  • 1
    $\begingroup$ When you say 'standard keyboard', can we assume that it's qwerty? $\endgroup$ – DXsmiley Jul 7 '15 at 11:09
  • $\begingroup$ @DXsmiley Yes you can. $\endgroup$ – user9377 Jul 7 '15 at 17:00
  • $\begingroup$ @CodeNewbie I'll add some soon. $\endgroup$ – user9377 Jul 7 '15 at 17:00

I am not particularly proud that I had to use the second hint, but using that I deciphered this.

The paper uses a skip cipher and the skip value is 54. Using this skip value and decoding the paper gives us

Skip has a prime factor that cleanly divides into the text length, so it can not be used.

54 has two factors, 2 and 3 (54 = 2133) and the text length is 75. So we cannot use 3.

So I think, to unlock the door, we need to key in the word


  • $\begingroup$ @Kslkgh, what was the cipher used for the wall carving? I tried several ciphers but couldn't break it. $\endgroup$ – CodeNewbie Jul 8 '15 at 16:12
  • $\begingroup$ @Kslkgh As Davide has pointed out in his answer, "Skip has a prime factor that cleanly divides into the text length, so it can not be used." is an error message! $\endgroup$ – f'' Jul 9 '15 at 11:37
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    $\begingroup$ I find this very amusing for some reason. Not only was the first stage forgotten, a completely flawed second stage answer was accepted. When the doors are basically "guess which rumkin ciphers I used", I don't see how this could happen. $\endgroup$ – Quark Jul 9 '15 at 13:45

Since this puzzle doesn't state that you die if you get the answer wrong, I'd go with

Brute force until the door opens

Also, the accepted answer just seem wrong to me, and here is why. To apply the skip cipher, rumkin was used, and the "deciphered message" is in fact an error message as we can clearly see from the javascript source code

if (HasAFactorMatch(enctext.length, inc))
  return 'Skip has a prime factor that cleanly divides into ' + 
     'the text length, so it can not be used.';

That's why using the interface controls to set the skip value, doesn't allow you to set certain numbers. So, if we implement our own skip cipher, or even do it by hand, we would probably never crack the code.

  • 3
    $\begingroup$ Actually, it did state that you would die if you get the answer wrong in room 1. But since most of us have died a couple of times before, and technically you can't die twice, why not give it a shot? :) $\endgroup$ – mmking Jul 9 '15 at 15:36
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    $\begingroup$ @mmking In that case this is the second time I die in this series :P $\endgroup$ – Davide Jul 9 '15 at 15:46

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