in a PC, how to access the digital output values of the sound input Analog to Digital converter?

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In a PHP program, I want to use the sound input (open mike) to produce random digital values. In theory this is possible, since there necessarily is at least one analog-digital converter on the mother board. However there is little info on the net on how to access such basic hardware functions.
Please note:

-I am in a PC under Windows 10, using XAMPP in localhost.
-I am not doing cryptography
-I want a real time signal, not records from a file
-I know the merits and defects of the different random signal sources. My choice is analog source.
-Some hardware or CPU have an analog random generator, these can be an alternative.

Thanks for your replies :-)