It seems to me you want a simple digest hash of the input string. Depending on your needs, Digest::CRC, Digest::MD4, Digest::MD5 or Digest::SHA1 might be interesting for you.

The OP asked for unique serials, and those algorithms can not guaranteed that, they just make repetitions unlikely (...I know, the requirements are quite vague).

If uniquesness is a hard requirement, I think that there are only two possible solutions:

• Track used serials in a file or database (using DB_File or SQLite, for instance).
• Make the serials transforming the originals in a way so that no information is lost (an injective transformation). For instance, if the data has some structure, use that knowledge to compress it, and then convert it to a human-friendly format.

salva,
Using the DB approach would allow the use of Data::UUID.
• If input string exists, return key
• If not, generate new one, store it, return it

Cheers - L~R

The only ways I can think of getting unique serials out of a user name are:

• pulling something out of thin air, like a random string, and stuff them in a database.

  You could use something like a CRC or a digest (like MD5), but clashes, however unlikely, are still theoretically a possibility, so you'd still have to store it. BTW you can append a secret key string to the user supplied value, before processing, to get a more unpredictable output.

• using reversible encryption. That way you cannot get clashes, but the result will likely be at least as long as the user supplied name, bar compression. You can use something as simple as ROT13, but if people mustn't be able to reverse engineer it too easily, use one of the more elaborate encryption schemes, with a password (AKA encryption key).

  If user names are sufficiently small, you may get by with just using a block cipher algorithm, i.e. virtually any encryption algorithm available, and just use a single cipher block. In that case, you're commonly limited to string of for example 8 bytes long. I'm not sure the latter is actually worth investigating, but most likely, as a result, you'll get serials with a more predictable length.

  For example, the module Crypt::CAST5 (or Crypt::CAST5_PP, if it must be Pure Perl) looks usable to me, straight out of the box.

I would use a one-way-function for that. See here for some explanation on one-way-functions. Although in your case it might be overkill, i.e. you don't state that it has to be difficult/impossible to calculate the original out of the generated code. Still a one way function does what you want. Take a look at some of the Crypt modules.

#!/usr/bin/perl
use Digest::MD5 qw/md5_hex/;

while(<>) {
  print md5_hex($_),"  $ARGV\n";
}
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