Hi,

I am trying to take two pieces of unique information and encode them into a 9 digit number with a static seed. I also need the ability to decode it given the proper seed. The two pieces of information are..

1) An IP addresss
2) A 9 digit session id

I thought about first base 10 encoding the IP address using the following code... 
unpack "N", pack "C4", split /\./, "64.58.79.230"

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and then just appending the 9 digit session id.

However, due to project restrictions, I need the final number to be a unique result, no more than 9 digits, and it must be a non-floating point positive integer. Is there some cipher or mathematical function that I could use to get this result? Speed is also an issue so the fastest algorithm would be preferred.

An example function would be... 
$uniq_result = encode("static_seed","64.58.79.230","542158235");
($IP,$sessionid) = decode("static_seed",$uniq_result);

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Security is not an issue really, so a seed might not even be necessary. Also, the ability to encode is much more important than the ability to decode. So if encoding without the ability to decode is all I can get, than I'll make do. As long as no unique combination of IP address and sessionid will produce the same 9 digit number, I'm ok.

Any help would be greatly appreciated. I've been racking my brain trying to come up with a solution.

Thanks

-scrill

In reply to integer encoder/decoder by Anonymous Monk

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