This article is basically an exercise in understanding ECDSA (Elliptic Curve Digital Signature Algorithm) from scratch. All I assume is some basic math and a willingness to pick up a bit of abstract math along the way. I try to explain everything as intuitively as possible, but, despite that, the article still demands some serious effort from the reader.
When I analyzed the Extended Euclidean Algorithm, one thing led to another, and I ended up writing a little intro to generating functions. You can even jump to that part and ignore the rest, if you want! Other readers may instead choose to skip that section altogether, as it's self-contained.
joezydeco•2mo ago
j16sdiz•2mo ago
and talks about fields and groups
mrkeen•2mo ago
Paraphrasing 'Group' from the article to see if I've understood it:
A set of elements G, and some operation ⊕, where
letmetweakit•2mo ago
b112•2mo ago
I'm mentioning this, as other people in this thread are discussing "explaining symbols you use", and you're using a non-standard symbol for +. I can easily imagine a circle around + making + a different operation, and wonder if it is so?
Aspirin I've bought in the past has a + on it, and its trademark is a + within a circle. That's why I've latched on what a "common person" might view the symbol as:
https://www.brand.aspirin.com/sites/g/files/vrxlpx46831/file...
Interestingly, I have University level math courses, but decades out of date, and have never run into that symbol. I see it here:
https://en.wikipedia.org/wiki/Direct_sum
jeroenhd•2mo ago
It acts as a normal +, mostly. When you're dealing with modulo math, the "normal" plus becomes a bit weird as there are rules attached to a number expressed as "(a + b) mod c", so mathematicians often use symbols like ⊕ to mean something like "+, but different". The second link you posted does the same, it acts sort of like normal addition, conceptually, except it's not done on actual numbers but groups.
In definitions like these, you may as well use a peace symbol or a picture of a frog; "some operation ⊕" means "there is some operation we write down like this, and it does this and that".
Another place you may find ⊕ is when it's used to represent XOR in some cases; (a + b) mod 2 is a bitwise XOR when operating on single bits (again, it means "normal addition except with weird rules", namely the mod 2 that makes you throw out anything larger than the last bit).
mrkeen•2mo ago
I specifically didn't use an already-existing symbol because then you wouldn't know if I'm talking about that symbol, or any symbol in general.
Integer-multiplication is associative, E.g.
and it has an identity element, E.g.avidthinker•2mo ago
edit: What I mean is that, as a consequence, the symbol used is not really important.