## ← 06-48 Identity Challenges Solution

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Showing Revision 1 created 06/29/2012 by Amara Bot.

1. So that probability is greater than 0.999,
2. and the reason for that is the only way she wouldn't be caught
3. is if the two people she spends the bill with
4. take exactly the same challenge.
5. The challenge is 10 bits long,
6. so the probability that would happen
7. is 1/2^10--1 in 1,024.
8. And 1 minus that is greater than 0.999.
9. So that's pretty high. If that's not good enough, we could increase m.