Figuring out how these are encrypted

The fear of every surveillance society: citizens protecting their own privacy with strong cryptography

Figuring out how these are encrypted

Post by MizukiTHPS on Mon Apr 18, 2011 12:05 pm
([msg=56425]see Figuring out how these are encrypted[/msg])

To make a long story short, I am trying to set up an internet application where users type in a code that appears on the back of an arcade video game card and they can look up their stats on a server that we set up. When the player puts the card in the system all their play data is sent to the server, paired with a 64-bit ID. Now sadly on the back of the card is 4 sets of 4 letters and numbers that seemingly have nothing to do with the 64-bit ID. So I need to figure out how the card reader goes from reading these 16 numbers and letters and turns it into the ID.

Here is a handful of pairs, first 4 rows are what appear on the back of the card last row is the ID

EPA5 ZZBW U05X ML11 E00410030D221BF2
HCTE BD34 C2KE TU13 E00410030D21C8CB
Z5M9 8RM2 3670 WX13 E00410030D221BF3
JL9T AJ68 DG87 SR13 E00410030D222458
RWKY X5E7 H52F 1015 E004100308686A02
6L56 0PG3 37PS DC15 E00410030E4FC345
Z40Y TLGR U68W CD18 E00410030D22094F
YLYY DAA6 542F 541B E00410030D21B12B
65LU U8PX YTP7 DC1L E00410030D21B0CF
YP68 UPY5 JUJZ 321L E00410030D21B25F
Y2ZN HGYS HC1A 671T E00410030D220048
NC35 8458 416M UT1Z E00410030D21E606

Any help would be greatly appreciated, after all this work it would be a really silly wall to get stuck at...
MizukiTHPS
New User
New User
 
Posts: 2
Joined: Mon Apr 18, 2011 11:56 am
Blog: View Blog (0)


Re: Figuring out how these are encrypted

Post by Goatboy on Mon Apr 18, 2011 3:30 pm
([msg=56427]see Re: Figuring out how these are encrypted[/msg])

The ID looks like incremental hex, and I can't find any pattern to the code except that they are alpha-numeric. You can try running some analysis against it, but I'm not certain that'll produce any real results.
Assume that everything I say is or could be a lie.
1UHQ15HqBRZFykqx7mKHpYroxanLjJcUk
User avatar
Goatboy
Expert
Expert
 
Posts: 2785
Joined: Mon Jul 07, 2008 9:35 pm
Blog: View Blog (0)


Re: Figuring out how these are encrypted

Post by MizukiTHPS on Mon Apr 18, 2011 4:57 pm
([msg=56430]see Re: Figuring out how these are encrypted[/msg])

So I just spent a few hours trying all types of combinations of representing the letters as numbers and trying addition, multiplication, subtraction, between each other, between sets, all kinds of combinations and none of them seem close. Where can I run these tests that you mentioned, I am trying anything and everything at this point.
MizukiTHPS
New User
New User
 
Posts: 2
Joined: Mon Apr 18, 2011 11:56 am
Blog: View Blog (0)


Re: Figuring out how these are encrypted

Post by Goatboy on Mon Apr 18, 2011 5:06 pm
([msg=56431]see Re: Figuring out how these are encrypted[/msg])

Well you already tried most of them. Looking for patterns is the first step. There is no second step beyond repeating different variations of the first step until you find something.
Assume that everything I say is or could be a lie.
1UHQ15HqBRZFykqx7mKHpYroxanLjJcUk
User avatar
Goatboy
Expert
Expert
 
Posts: 2785
Joined: Mon Jul 07, 2008 9:35 pm
Blog: View Blog (0)


Re: Figuring out how these are encrypted

Post by r-ID on Wed Apr 20, 2011 8:20 pm
([msg=56546]see Re: Figuring out how these are encrypted[/msg])

take a look at this:
E00410030D221BF2 EPA5 ZZBW U05X ML11
E00410030D221BF3 Z5M9 8RM2 3670 WX13
two very close ids have very different codes, i think it is pointless to look for patterns. I also noticed that symbol at index 15 is always 1, so i think last two symbols are for the checksum or something (similar like credit cards numbers)

Btw, why do you think id has something to do with the code at all? How did you get those ids? I think the system is something like: by incrementing id, random symbols were generated and table were stored. So there is no way to do this except to get that table. Or... random symbols were generated there is an algo to check if code is correct and id is created when serial is registered.
r-ID
Poster
Poster
 
Posts: 172
Joined: Mon Dec 29, 2008 6:04 pm
Blog: View Blog (0)


Re: Figuring out how these are encrypted

Post by Goatboy on Wed Apr 20, 2011 9:33 pm
([msg=56551]see Re: Figuring out how these are encrypted[/msg])

It looks like the ID is incremental with a set prefix, and the code is just a custom hash of the ID.
Assume that everything I say is or could be a lie.
1UHQ15HqBRZFykqx7mKHpYroxanLjJcUk
User avatar
Goatboy
Expert
Expert
 
Posts: 2785
Joined: Mon Jul 07, 2008 9:35 pm
Blog: View Blog (0)


Re: Figuring out how these are encrypted

Post by r-ID on Thu Apr 21, 2011 5:41 am
([msg=56575]see Re: Figuring out how these are encrypted[/msg])

usually codes and serials are random generated symbols i don't think it's a hash.
r-ID
Poster
Poster
 
Posts: 172
Joined: Mon Dec 29, 2008 6:04 pm
Blog: View Blog (0)



Return to Crypto

Who is online

Users browsing this forum: No registered users and 0 guests