Therefore, if cryptography is used properly, there is no way to achieve what's asked short of reverse-engineering the 'software program' or somewhat access what 'generates the response', both of which are off-topic. Blowfish algorithm is a block cipher algorithm, its strong, simple algorithm used to encrypt data in block of size 64-bit. The key is used to encrypt and decrypt data whatever the data is being encrypted or. If the number 'responded' is an arbitrary function of the number 'supplied', there are $10000^,n)mod10000$. Key generation is the process of generating keys for cryptography. How would I approach such a problem and can it even be done at all? Since the response is always a 4 digit number that is generated from another 4 digit number I assume that there is only 10,000 possible codes that relate to the 10,000 possible 'seeds' so I don't think this should be very hard for me to reverse engineer or brute force, essentially I'm looking for a direction where to start.

I'm confident that once I figure out what the underlying algorithm is to convert from one 4 digit challenge to the 4 digit response then I will be able to code me a little utility to always get the response. Ideally there would be some utility or a formula that I could apply or tweak here. Right now I have one sample pair (7153 - 9533) to work with. I'm now looking for whether it is possible to come up with the algorithm that is used to generate the response and if so how. CodeIgniter Encryption Keys - Can be used for any other 256-bit key requirement. Memorable Passwords - Perfect for securing your computer or mobile device. To access a specific functionality it runs a challenge-response-like authentication, that is it generates a numerical 4-digit PIN and expects a 4-digit numerical PIN in response. Generate a New Set of Random Passwords and Keys. I have a software program running on a piece of hardware.

Key generator algorithm