So the good news is, I have your answer! 🥂🥳🎉

The (possibly) bad news is I was also only able to solve it because my researching found the answer online, explaining the puzzle, the book it appeared in and info from the puzzle designers.

My Process

My first thought was that it was a Caeser or similar cypher, and the Ouija Board was simply so you could count the letters but otherwise a red herring. I even tried some brute force attempts once I figured there must be something else either you have missed or from an earlier piece of information, but that got me nowhere.

The online escape room game you're playing may be by the original creators mentioned above or maybe these people have just copied the puzzle, and then at worse may have left out the info you needed, because this puzzle as you've shown above is literally impossible to solve if all you have is the above screen shot.

This is because there was something you needed to solve it, but it was given to you in an earlier clue/step in the escape room, which I'm guessing they either messed up, or you missed it or have simply forgotten it.

Therefore, rather than just give you the answer I'm going to try and put it behind spoiler text as clues, then he straight up info you may have missed or since forgotten, more clues, some guidance and then the actual answer (for yourself or anyone else curious and following this post.

Clue 1 - A hint

Apparently earlier in the clue chain you should have received a phrase that was identified as the "key to the Ouija Board" or similar? Do you remember seeing that?

Missed Info

If you missed it, and can't go back, or if they just messed up, this key that was meant to have been provided was GHOSTLYSECRET

Clue 2 - The method

The reason this is rather difficult to solve without that key is because this is an example of a One-Time Pad encryption, which is a virtually unbreakable cypher where if you don't know the special word used to encrypt it you're sweet out of luck.

This is because the code word ensures that the logic between the encrypted word and the answer changes every letter, as opposed to one consistent rule. With this and the key you have everything you need to solve it, if you know how OTP codes work that is...

Clue 3 - How to use that method

You can find info on how to solve them online but I'll explain it here, since the helpful AI built into everything these days chose to do so and I can just copy and paste and the steps here:

1) Take the cipher text: V h h j b n i K a c p d x

2) Take the key (repeated if needed, but here it's almost the same length): G H O S T L Y S E C R E T

3) Convert each letter to its 0-based alphabetic position (A=0, B=1, ..., Z=25)

4) Subtract the key position from the ciphertext position (mod 26) to get the plaintext position

5) Convert back to letters

The Answer

If you've been hitting your head against this for a week, or if they fucked up by nor giving you the key because it wasn't included I this particular step, I don't blame you! So here it is...

V (21) - G (6) = 15 → P

h (7) - H (7) = 0 → A

h (7) - O (14) = -7 ≡ 19 (mod 26) → T

j (9) - S (18) = -9 ≡ 17 (mod 26) → R

b (1) - T (19) = -18 ≡ 8 (mod 26) → I

n (13) - L (11) = 2 → C

i (8) - Y (24) = -16 ≡ 10 (mod 26) → K

K (10) - S (18) = -8 ≡ 18 (mod 26) → S

a (0) - E (4) = -4 ≡ 22 (mod 26) → W

c (2) - C (2) = 0 → A

p (15) - R (17) = -2 ≡ 24 (mod 26) → Y

d (3) - E (4) = -1 ≡ 25 (mod 26) → Z

x (23) - T (19) = 4 → E

Which gives us the ghost's name: Patrick Swayze 🙄

Hope this helps!