The randomness of vanitygen is secure enough? If two people running vanitygen 1abcdefg What is the chance that both of the person will get the same public key &amp; private key?

I hope that the answer is less than 0.0000001. But for this vanigygen need to use random algorithm (not simple while(true){ i++; test()}).

My question is: Usually when I create wallet, using http://bitaddress.org I need to Move your mouse around to add some extra randomness, but vanitgygen do not do this method.

By inspecting the code of vanitygen in GitHub I see that they use random functions. Can I trust it? Is it really random? How it can be secure? Is it use the machine time or what?
If two people running vanitygen 1abcdefg What is the chance that both of the person will get the same public key &amp; private key?


If a billion supercomputers each tried a billion keys per second for a billion years, the odds of a key collision would still be less than one in a billion.


  I hope that the answer is less than 0.0000001.


Yes, much less.


  But for this vanigygen need to use random algorithm (not simple while(true){ i++; test()}).


It just needs a random starting place. You can increment from there if you want to. The number of possible starting places has 77 digits when expressed in decimal notation.