I recently came across this post on Puzzling SE, and after some heavy research I haven't come up with an answer. The issue is that in Deus Ex: Mankind Divided, there is what appears to be an encrypted e-mail in the pocket secretary:

From the game files, this appears to be the string:

FILE: client.pld31bf3856ad364e35.id
CecKIjBrWWr|9Vo2DN6DOWK|86lQSYxno0s|6c4yEcxnoGs|FxAgwKsaX0I|5LMLADBrWGr|SecLIdbTR04|FxAgwMbTQW4|9r2mtqyMtmX|AGVGov0nYGu|8zg5cz0nY0u|EX@DJoCyext|F#6XUkCyN0W

If you treat the pipes as column separators, we get 13 rows of 11 characters each:

CecKIjBrWWr
9Vo2DN6DOWK
86lQSYxno0s
6c4yEcxnoGs
FxAgwKsaX0I
5LMLADBrWGr
SecLIdbTR04
FxAgwMbTQW4
9r2mtqyMtmX
AGVGov0nYGu
8zg5cz0nY0u
EX@DJoCyext
F#6XUkCyN0W

However, this is where the trail often runs cold, though there have been many theories surrounding the e-mail; unfortunately, none seem to have been confirmed, nor denied.

---

Has anyone decoded this message?

4

1 Answer

Very hard to find out. We don't even know the set of character used to encrypt that message (if there's a message behind it). It's not ASCII standard because of @ and #, and it's not a standard Base64 encoding for the same reason (I already tried every source of characters, btw).

So it must be a sub-set of Unicode, my guess is a ROT-47 alphabet. This, at least, contains every character used in the email:

!"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{|}~

or maybe a custom set of Base64 containing those two symbols (as per @NickKennedy's comment):

ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789@#

Now the hardest part: discover the encryption method used.

I had no luck with Caesar's cipher, I tried all combinations using a quick Java program, even with different alphabets.

Other methods like Polybius, Delastelle, Atbash, Rail fence, Playfair and even Enigma machine seems unlikely because we have both uppercase/lowercase letters, numbers and those 2 symbols.

So my guess will be on Vigenere cipher, since it was used for another encrypted email:

But again, we may have the same problem: "where's the goddam key?". That enigma already had a big hint to solve the puzzle, since...

the actual key to decrypt it was a sentence in the email.

I don't own the game so I can't investigate, but the key may be, again, under our noses...

Anyway, nobody has decrypted this yet in years, so maybe there's nothing to discover.

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