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kenshamir[m]
<philogy "<a_L - 1 - a_R, y^n> = 0"> This equation essential says that aR = aL - 1
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philogy
Yeah, I just don't understand why the challenge vector y^n isn't enough and you need the additional randomness from z
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kenshamir[m]
If aL is really a bit vector, so just 0s and 1s, then aR is 0 when aL is 1 and aR is -1 when aL is zero
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kenshamir[m]
<philogy "Yeah, I just don't understand wh"> It might help to think of it as an interactive protocol, where you are trying to convince me of an equality
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kenshamir[m]
You want to convince me that X + Y + Z = 0
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kenshamir[m]
If I leave you to compute it and tell me the answer you could cheat
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kenshamir[m]
You could make X and Y cancel out with Z or you could trivially tell me that it’s zero
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kenshamir[m]
So what I can do is the following:
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kenshamir[m]
You send me a hiddenX and I send you C1
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kenshamir[m]
You then send me hiddenY and I send you C2
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kenshamir[m]
And then lastly you send me hiddenZ and I send back C3
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philogy
I understand the general idea about why you need challenges in order to prevent "forgeries" but my question is why doesn't y^n suffice in the first step, why do you need the additional challenge z?
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kenshamir[m]
However you could as mentioned above, manipúlate Y and Z so that X + Y + Z = 0
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kenshamir[m]
But X, Y or Z are not 0
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kenshamir[m]
What I do is I use the challenges we generated before and instead ask you to prove that:
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kenshamir[m]
X * C1 + Y * C2 + Z * C3 = 0
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kenshamir[m]
If X, Y and Z were zero, then multiplying it by this random challenge will not affect the outcome
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kenshamir[m]
But we must use the random challenge, as a bad actor could manipulate the equations when they are being combined
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kenshamir[m]
If you want to know when to use a challenge, it would generally be whenever you say that word “AND” . It’s about generalisation, but works most of the time
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kenshamir[m]
So we want to prove that v can be decomposed into aL AND that aL only consists of bits
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kenshamir[m]
Not sure if that helps
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kenshamir[m]
It’s quite late where I am, I can stay around for another minute or so before I hit the sack
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kenshamir[m]
For the other equations, if you do a small example, I think it might become clearer
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philogy
yeah thx for the help, it's late here too. gn
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kenshamir[m]
night waves