Thanks for trying. I give it 24 hours, if the enigma is not solved by then i'll post a step by step.
And, yes, the code has been broken ! But the prize is still on the table.

Got it!

The code was VBKB-4XV3-9AKC-PTTY. I'll edit the post in a few minutes to explain step-by-step how you got there.

Thank you for the giveaway, had this in my wishlist. =)

EDIT: Gift codes only have 4 sets of 4 alphanumeric characters, so the first one is obviously the key, as hinted in the first hint. So 2CV13N is the key, and TZIZ-1VT0-6BIA-NRRZ is the part of the code you have to decrypt.

Considering the third hint, you had to break down the key in 3 parts: 2C, V1, 3N. Now, the second hint tells you the shift corresponding to each of those. If 1C transforms a B into a A, then it follows that 2C transforms a C into a A, and if 1N transforms a 3 into a 2, then it follows that 3N transforms a 5 into a 2 (V1 is in the hint).

Now you need to figure out which shift applies to each alphanumeric character. That's were the first hint comes in. The fist set is the key, the second is all made up of sees (CCCC), the third has hens (numbers) surrounding sees (NCCN), in the fourth only the last 2 are sees (NVCC! the first character is a number, and the second one has to be a V since it's neither a number or a C) and in the fifth one the last is not a see (VVVC!, following the same logic as before).

Voilá, the code is broken. One last thing to remember is that since the code given was used to change the real code into the cyphered one, to decrypt it you have to revert the shifts. So when you have a C, it leaps 2 letters forward, when you have a V it leaps 1 letter backwards and when you have a number it leaps 3 numbers forward.

I hope I was able to explain it clearly enough...

EDIT2: I wouldn't have gotten it without the clues.

The prize has apparently been redeemed by Tannath

The solution was :

step 1 : the riddle tells you the first group is the key to the cypher and the nature of the initial alphanumeric characters:

(c=consonnant, v= vowel, n = numerals )

cccc-nccn-nvcc-cccv

Step 2 : the key tells you Cs have been advanced by 2, Vs have been shifted back by 1 and Ns adavanced by 3

2222-3223-3(1)22-222(1)

Step 3 (optional) : reversing this allows you to deduce the Vernière cypher

CCCC-DCCD-DZCC-CCCZ

Step 4 -inputing the cypher and cyphered text into a Vernière solver
- or simply applying the shift obtained in (2) to the cythered text gives you the result

VBKB-4XV3-9AKC-PTTY

Congratulations !

Great idea for this giveaway! :)

Thank you so much, Phc7006, for offering an alternative prize and such a good one, indeed (SimCity 4).
Awesome giveaway!

Thanks !
You're welcome !

That was an awesome giveaway - I enjoyed everything about it, except for the fact that I never figured it out.

The only thing I figured out was the fact that the first group was the key - before you posted the rhyme. That wasn't hard to figure, most GOG keys are four groups of four. The first group was the only thing that didn't fit.

Beyond that, I never figured it out. I took "Enigma" too seriously. I was trying to figure out how to apply the first group to an Enigma machine rotor settings.

One again, thank you. It was a fantastic idea for a giveaway.

It really feels like I worked for it instead of just being plain lucky in a lottery, and I like the feeling. =)

Enigma is probably the best known exemple of a polyalphabetic cipher, that's why I used that name. It's not clear when such ciphers were used for the first time. Caius Julius Caesar used a simple shift code during the Gallic wars. But at least one source refers to the use of variable cipher keys in Augustean times. Complex codings appeaed with the expansion of trade, in the 1400's. In the early polyalphabetic ciphers, one had to rely on a key, provided by a given sentence, by biblical references. In this case, the riddle emulated that.

Anyway, thanks to all participants. I still have few gift codes under the hand. But not really new, attractive games . I still hope GOG will release something else than a platformer or tower defense or shooter game in the coming weeks ( these three genres are absolutely not inspiring me ) ,

Flavour of the day (or year), I guess... mostly uninspiring for me as well, good thing I have a long backlog...

I missed this fun ga but I wanted to give props to the OP for gifting not one but two games.

Congratulations to Tannath and mrkgnao for solving this puzzle.

This sums it up nicely, plus the fact that beer and decryption of "enigmas" don't go hand in hand, but great GA never the less
Thanks for the clarification, I looked it up a little bit on wikipedia and other sources.
Speaking about enigmas what do you think about the Voynich Manuscript. Now that's a tough nut to crack :)

A tough nut indeed. Could be written in a specific alphabet ( but there seems to be no rosetta stone in this case ) But it could very well have been an elaborate, sophisticated scam, produced in the XVIth century to extract as much money as possible from the nascent interest in science amongst the wealthy of the time.

+1 for the giveaway!

Nice theory, I guess it's one of the things we'll never truly know