Working out an algorithm??

techguy

Hi,
Is it possible to work out the algorithm used for generating a code from another code if you have both codes??
e.g you block something and get a code.. This code you have to send away to your service provider (of whatever service) for an unlock.. This has happened to me with 1 particular service and I now have both codes. Is there a way to work out the algorithm that is used?

By the way this is not for malicious use, just an interest..

Thanks,

Hakko

Hobbes

with such a small dataset. no.

techguy

could you work out a set of algorithms to generate a list of possible codes or anything?

Mutant_Fruit

If Code A is 1, and Code B is 100, there is no way in hell you can find an algorithm to link them both that also generates other correct combinations.

By any chance are you trying to unlock mobile phones? There's plenty of apps out there that do that.

democrates

If you think about the maths there are infinite ways to get from one number to another.

But in the real world there are a small number of ciphers in use. If you do a bit of research on the application area you may find some industry standards. Thing is they tend to anticipate such attacks and a private key is probably involved as well as strong encryption to make brute-force attacks unfeasible. That said there's always a way if you have the device that decrypts (eg with drm you usually have the content, the key, and the algorithm).

If it's some in-house effort and they're just using an old hashing algorithm like md5 you could do a brute force generation of results until you find a match, but it's unlikely that security for anything really valuable is that lax. That said...

I'll never forget Clifford Stoll's 'The Cuckoos Egg', and more recently that hacker was caught looking for roswell-based free energy technology and found a bunch of wide open open government systems.

Hobbes

Some of the things they throw into those sort of numbers.

1. Checksum. Generally its the last number or second last two and they have thier own formula which is run against the remaining numbers and generates that number. This alone stops casual guessing.

2. Trap numbers. They will take a handful of numbers and mark them as invalid. This is to stop someone who has cracked the checksum from mass running the numbers. Generally a trap number is watched for in the device and flags it as an illegal number rather then just not working. Results can be device being permantly deactivated to someone sending a copper around depending on what it is your trying to do.