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?


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.