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> How am I going to explain this to my wife? I don't know. What's your wife's background? If she already knows what one-way functions are, you could just exp
by cjbprime 10y ago
> How am I going to explain this to my wife?
I don't know. What's your wife's background? If she already knows what one-way functions are, you could just explain that we've found collisions for the first time in an old one-way function that was used for file authenticity but isn't used much anymore because we knew ten years ago we were probably going to start finding collisions in it.
If she doesn't know what one-way functions are, it seems like something that could be explained with examples to an average person who was interested in learning?
- modalduality 10y agoOne-way functions are not cryptographic hash functions, which have the three properties preimage resistance, second preimage resistance, and collision resistance. For example, say f(x) is a one-way function. Then define g(0x) = f(x) g(1x) = f(x) Here given some z, it's easy to find another z that maps to the same output, just flip the first bit. However, g is still a one-way function: Assume we could break g with non-negligible probability, that some program A(y) outputs x such that g(x) = y with probability p. Then say someone gives us q = f(a) for some a. We can compute A(q) that will either give us 1a or 0a by the definition of g with probability p. In either case we can discard the first bit to find the preimage for a. By contradiction, g is a one-way function.