The ones that bid the most ciphers get preference down to people that only bid a single cipher, then after that people that did not bid a cipher at all are randomly selected. So:

Dude that bid 10 cipher auto-top spot, guaranteed entry
Dude that bid 3 ciphers (next highest) , guaranteed entry
14 people that bid 1 cipher guaranteed entry
33 people that did not bid a cipher: 32 are randomly selected , 1 person doesn't get to enter.

If it was just 50 people bid 1 cipher, the game would randomly select from them 48 people and 2 people would get cipher refunds.