Re: using CRYPT but restrict alpha-numeric

On 07/12/2021 23:11, [email protected] wrote:
> Hello.
>
> I'm looking at the various CRYPT / one-way encryption commands and i
> was wondering if there is a way to create a crypt but restrict output
> to alpha-numeric (a to z, A to Z and 0-9) without the special
> characters ?
>
> Basically ive got a starting reference - numeric over 10,000,000 and
> other numbers and want to do a crypt (or something) but exclude
> special characters from the crypt result.
>
> The best I can think of is to do a crypt (or whatever) etc and then do
> a preg_replace to remove the special characters etc..
>
> The result will be shorter (length), but will be an alpha-numeric crypt.
>
> --
>
> Gordon.

What problem are you trying to solve by doing this?

`crypt` on its own doesn't tell us much as it's a library that can use 
multiple algorithms.

It should be noted that (password) hashing algorithms already use a 
restricted character set that is basically alphanumeric plus a few other 
characters. The current defacto standard for password hashes is the 
modular crypt format which you can see explained on the Description and 
Version History sections of https://en.wikipedia.org/wiki/Bcrypt and the 
Radix-64 character set used is described on 
https://en.wikipedia.org/wiki/Base64#Radix-64_applications_not_compatible_with_Base64