You can truncate the result from md5_hex.

But hold on.

A 128 bit number in base 16 uses 32 digits, so chopping all but 19 of those results in a 40% drop in hash size.
A 128 bit number in base 62 uses 22 digits, so chopping all but 19 of those results in a 14% drop in hash size.

If you go the truncation route, don't use base 16, use base 62 (0-9,a-z,A-Z).

By the way, you'd need 107 different symbols to represent an arbitrary 128 bit number using no more than 19 symbols, but there are only 95 printable ASCII characters (counting the space, but not counting tab, line feed, etc).

In reply to Re: Character Length Requirement & String Conversion by ikegami
in thread Character Length Requirement & String Conversion by bpthatsme

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