Elliptic Curves: The Great Mystery

Re:Elliptic Curves: The Great Mystery by josh2600 on Tuesday January 17, 2023 @03:58AM (#34410487)

Elliptic curves are insanely useful. The Dalek library which we use at MobileCoin uses an Abelian group of prime order to attempt to avoid cofactors which can result in double spends (or worse depending on the number of cofactors). Other curves in crypto have different properties but the cofactors attacks are particularly insidious as they are hard to detect until after they’ve been exploited and the consequences can be very significant (imagine hypothetically spending 2000btc 8x from a single txo).

All of this stuff is fun. If you’re interested in working on things like this, particularly in at-scale applied cryptography, we’re always hiring.

MobileCoin.com/jobs

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Re:Elliptic Curves: The Great Mystery by testtesttesst on Tuesday January 17, 2023 @04:41AM (#34410718)

An abelian group of prime order has no nontrivial subgroups by definition. How can you "attempt to avoid" cofactors -- there are no subgroups?

Great ad to not buy your coin.

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Re:Elliptic Curves: The Great Mystery by acer4666 on Tuesday January 17, 2023 @06:18AM (#34411257)

Which curve do you use?

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Re:Elliptic Curves: The Great Mystery by josh2600 on Tuesday January 17, 2023 @06:58AM (#34411476)

https://github.com/dalek-cryptography/curve25519-dalek

25519, ristretto group.

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Re:Elliptic Curves: The Great Mystery by acer4666 on Tuesday January 17, 2023 @09:23AM (#34412680)

There's a weird sort of doublethink going on in your post. You're trying to attract talent that knows cryptography but seem to be using the same cryptobro snake oil you presumably use to sell your product (dude...imagine someone spending 8x the bitcoin!!!1! Even tho bitcoin uses secp256)

You also seem to be trying to give the impression you're doing something new and interesting rather than just deploying ristretto255 like everyone else. But you don't want to be caught rolling your own crypto, so you're being deliberately vague.

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Re:Elliptic Curves: The Great Mystery by josh2600 on Tuesday January 17, 2023 @10:39AM (#34413759)

I think this is an unfair characterization. My point was to try to help individuals mentally model what could happen in the event of a cofactor attack. I think it would’ve been more confusing to say “imagine spending a txo 8x!” Because most people even in crypto don’t know what a transaction output is :/.

Please note that we didn’t roll or build Dalek, so again, this is a mischaracterization.

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Re:Elliptic Curves: The Great Mystery by HelloNurse on Tuesday January 17, 2023 @07:17AM (#34411598)

Do you mean you use known compromised/unreliable algorithms with a significant probability of allowing someone to steal someone's money?

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Re:Elliptic Curves: The Great Mystery by oleganza on Tuesday January 17, 2023 @07:28AM (#34411676)

The point of the OP was that Dalek library provides API to Ristretto (https://ristretto.group) which is a proper mathematical prime order group, unlike stock Ed25519 API that exposes cofactors and caused famous issues in Monero.

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Re:Elliptic Curves: The Great Mystery by josh2600 on Tuesday January 17, 2023 @07:38AM (#34411732)

Yes this is my point.

This removes cofactor attacks which famously allowed multi-spend. Dalek removes or severely reduces this possibility.

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