I'm using 512sha2 hashes as an id, however I would like to use a shorter string, what options are there available?
I'm thinking not using all the hash, say the first 50-100 characters to lookup the whole hash and get to work that way.
If there is a collision at say 50characters (2 hash id's have the same first 50 character) then what should I do?
Is there a specific term for what I'm attempting to do?
Well, Bitcoin takes the SHA256 hash of the public key and turns it into an address by hashing with RipeMD-160 and then Base58 encoding the result (and some other stuff). Perhaps something like that?
Also, if you run Bitcoin in debug mode and double click on a txn, it will give you a very short (16 char?) string which BlockExplorer knows what to do with. Theymos might be able to tell you what exactly that string is.