# It's Safe To Follow Instructions

Below is a safe, requiring a four digit passcode. To find the correct code, all you need to do is follow the instructions.

There was a lot of ciphertext underneath instruction six which read:

OQIPM E JZHPM AFUDLK HVYBX NBCBA MBZR JHQIA CQIOM WHTMVIPE BJL XBGJTW QA FVFLTH PJXEBHCM ZE ESJWK K TBHMT Z ESJWK O LBE XPN

What 4-digit number will open the safe?

EDIT: Just in case the steganography tag doesn't make it obvious, this puzzle requires basic image editing software.

EDIT 2: This is a fault on my behalf, but due to the nature of this puzzle I can't change it now; when you have found the hidden instructions that relate to step 3, group the instructions so that you only get 4 pieces of information, not 8. Sorry!

• Am I going mad, or did you already post this same question earlier? – Rand al'Thor Jan 17 '17 at 1:11
• I deleted that one, I had to revise something, thankfully it didn't look like people had made too much headway on the old version – TheGreatEscaper Jan 17 '17 at 1:11
• There is 4 single letters in the cipher so possibly stand for 7-8-9-0, and their following text might be the command for those numbers. Also the first text after "The code is" is OQIPM so perhaps that's the key to break a cipher somewhere.... Or maybe all I said is gibbering and doesn't help at all haha. – stack reader Jan 17 '17 at 1:22
• @stackreader Nice to see someone thinking ahead, but the instructions actually are helpful. Start from the top, and always be wary of the wordplay tag. – TheGreatEscaper Jan 17 '17 at 1:30
• Blimey. Having seen the progress made on this so far, this looks like an awesome puzzle. – Rand al'Thor Jan 17 '17 at 15:02

The four-digit number is:

1438

This answer is terribly out of sync with the puzzle's intended solution. It turned out that many of the steps can be skipped.

Only part of this solution is my own. I rely heavily on partial solutions given in other answers and comments.

First, LeppyR64's has found out ...

... that there is hidden information in some of the letters.

Working from that:

Instruction 1 says "Towards info", which apparerntly should hint at the two 2's in the picture that guard/ward information. (The OP has explained that in a comment below.)
Instruction 2 says "Tenor" key. Decrypting the line below with the key TENOR doesn't yield anything useful, though. It turns out that (a) the key isn't really a key to the cipher below and (b) is a bit cryptic: Ten in Roman numerals is X, so the instruction says XOR key.

XOR or exclusive or is a binary operation that yields 1 when both inputs match and 0 otherwise. The two 2's can be overlayed and xored, so that pixels that are different in both 2's are white; pixels that are the same in both 2's are black. This yields:

It says "Holistically 4".

Instruction 3:

Using the key HOLISTICALLY as a Vigenère key for instruction 3 yields:

RR FROM ODD GAP

Instruction 4:

The instruction "Invert key" has the word "Lichtenstein" hidden in the first E.

Unfortunately, my solving stalled here.

Skipping several steps, Deep Purple found that ...

... the long text message can be be decodes with the Vigenère key LICHTENSTEIN. It reads:

DIGIT A WHOLE NUMBER DIGIT FORTY FIVE ROMAN RIGHT SUBTRACT THE EXTRAS IN UNDEAD CREATURE XX LOWER G LOWER S LOWER K DOT PNG

That, as the keen PSE denizen will immediately spot, is an URL on imgur. The last three characters and the file extension are given clearly: ..gsk.png. Apparently, the first two characters are two digits.
I'm not so sure about the roman numbers and the undead, but a bit of brute-forcing leads to the following image:

(Yes, cheating isn't fair, but once you've skipped some steps, you're already in the low-moral zone. Sorry for that.) The upper blank is a nonogram, as Mike Limburg has found out. Thankfully, he has already solved it:

Now the last step:

The black pattern in the nonogram is a detail from the original instruction image: It is part of the N in "Instrucions" which is underlined.

We can now overlay the pink mask so that the nonogram matches this N:

The four windows in the mask now show the combination for the safe, this time white on black. Voilà!

• Nice progress! You've been following some instructions without realizing... if you can work out where you are in the instructions, then you should be able to crack one cipher. – TheGreatEscaper Jan 17 '17 at 7:16
• Hey, remember to sort out instruction 3 before instruction 4... 'invert' will make a lot more sense then! Also, since you've already passed it and it's not important now, the meaning of instruction 1 is a wordplay that sounds like 'two wards info', where the definition of wards is guards. 'Two guards information', which is the signpost to examine the twos, and also leads on to the 2s being the subject of the XOR in the next instruction. – TheGreatEscaper Jan 17 '17 at 12:06
• I've accepted this answer for now, since you have got the right code :) Should I leave the other parts of this puzzle open, or explain the clues/steps that were skipped? – TheGreatEscaper Jan 17 '17 at 15:59
• Yes, why not? After all, those parts weren't meant to be skipped. (I've written the latest version of the answer in abit of a rush. Let's see whether I or someone else can fill in some of the skipped steps.) – M Oehm Jan 17 '17 at 17:00
• Oh, I see you've already written a wrap-up post. – M Oehm Jan 17 '17 at 17:01

Following from M Oehm if you use "lichtenstein" as the key on the coded text below the puzzle we get

digit a whole number digit forty five roman right subtract the extras in undead creature xx lower g lower s lower k dot png

• This puzzle seems to lend itself to being solved out of order. – M Oehm Jan 17 '17 at 14:26
• also with your working out that "Ten"or was really XOR then I assume that XLV will come in to this somewhere with the "forty five roman"... is this spelling out another key? – DeepPurple Jan 17 '17 at 14:31
• Aren't you missing a few characters at the end of that plaintext??? – TheGreatEscaper Jan 17 '17 at 14:33
• Yes, it's missing DOT PNG. Looks like a mask for the instructions. – M Oehm Jan 17 '17 at 14:35
• Nice found @MOehm, here is that nonogram filled in which can be found at your url: imgur.com/a/Pgq1k – Mike Limburg Jan 17 '17 at 14:48

Helping with the .

Jacking up the brightness and contrast yields this image:

• Seriously? How did you get the idea of changing the contrast o.o. I would have never thought of that in a 100 years haha – stack reader Jan 17 '17 at 3:10
• @stackreader Actually the first thing I did was run the histogram of the image to find out that there were pixels that were not white or black. Then I made this step. (I used irfanview for the histogram, gimp for the contrast) – LeppyR64 Jan 17 '17 at 3:13
• I feel like I still have a long way to go as a member of the puzzling community... – stack reader Jan 17 '17 at 3:15
• @stackreader Everyone has different skillsets. You'll notice I don't solve a lot daily. There's always something to learn. And don't forget, the puzzles don't stop here. :) – LeppyR64 Jan 17 '17 at 3:17
• Cool! I flood-filled the white part and didn't see anything. So this lazy steganographer concluded that there was nothing to see. :( – M Oehm Jan 17 '17 at 6:23

SKIPPING STONES:

@Moehm has arrived at the correct code above, but there were a few things left out. For anyone interested, here's the stuff that happened in between! All spoilered, of course, in case there's anyone still interested in puzzling it all out completely.

INSTRUCTION 3:

...was correctly decoded as RR FROM ODD GAP. This is a step I liked a lot, so I was a bit sad that it was skipped (although that is a fault of the puzzle construction). It's another steganography step, but it's not to do with colours!
You may notice that the text on multiple lines of the instructions goes in and out of alignment, that is because not all the spaces are the right size. There are 5 pixels in a normal space, and 15 pixels in a normal gap between words. There are several spaces/gaps that are a pixel or two too short, and looking at the letters to the RR (right right) of these, we get O NW NE NE. This appears to be compass directions - and starting from the 0 on the keypad, we get 0753. Only after posting the question did I realise I didn't hint at this being 4 digits - and following NWNENE step by step also provided an invertible number! Oops. The edit 2 hopefully cleared this up.

INSTRUCTION 4:

Invert 0753 to get ESLO, the key for instruction 5.

INSTRUCTION 5:

When deciphered, reads THIRD E KEY. This is where LICHSTEIN was supposed to come into play.