AH, but that's actually kind of hard. Impossible even within the confines of pure software. You would need some sort of physical piece of hardware to collect entropy, otherwise you're just getting pseudo-random numbers which APPEAR random, but are actually sequential and pre-determined based on your initial seed number.
And that kind of hardware is very specialized, AND AWESOME:
It is true that software can only generate pseudo-random numbers, but the deviation from being purely random is virtually negligible.
This summer I wrote numerous programs to test the stability of different processes, and used software random numbers a few times. I brought up the concerns to my supervisor (who is a programmer) about it not being purely random, but he said it's so negligible that for our purposes it shouldn't matter, especially since the system I am analyzing uses software random numbers anyway. I did numerous tests on generating random numbers to check how random it is.
For instance, with a simulation of 5 million numbers generated, I graphed them and recorded them extensively, and ran the simulation multiple times to see how each run compares to all previous runs. Even with a number as large as 5 million numbers generated, each run had significant variations, and overall it displayed results one would expect from random numbers. For instance, with 1 million coin flips, sometimes there would be 500,987 heads, and sometimes there would be only 498,654 heads.
One thing you can do is take the random number that comes from the seed, and put it through more processes to increase it's randomness. Like, have a computer program with a loop of 5 million generated random numbers, and for each run through the loop add the newly generated random number to the last one, so you're building a larger and larger random number that is constructed from the sum of all random numbers generated so far. Then, for each run through the loop, determine the last digit that this number ends with. If it's 0,2,4,6, or 8, then call it "heads". If it's 1,3,5,7, or 9, then call it "tails". I'm sure someone who actually has a lot of programming/advanced math experience (unlike me, with only basic programming experience and undergraduate level mathematics) could think of various mathematical ways to increase the randomness way more. There are tons of ideas online I'm sure, and don't some people do this sort of thing for doctoral thesis and such?
For the purposes of the test, if a deity can influence the laws of physics to form a certain outcome of a physical coin flip, he can similarly influence computerized coin flips.
I wonder how much that cost to make...