Post
Topic
Board Altcoin Discussion
Re: CryptoNote technical discussion and Boolberry vs Monero Chess Challenge
by
boolberry
on 18/01/2016, 20:57:34 UTC
Not chess related but besides anonymity I think it is worth reminding people of another technical reason that makes CryptoNote coins much different than bitcoin.

CryptoNote uses the Schnorr signatures algorithm instead of Elliptic Curve Digital Signature Algorithm used by bitcoin

I think an elliptic curve discussion would be on topic if we have enough volunteers both willing and competent enough to discuss it.

https://en.wikipedia.org/wiki/Elliptic_curve_cryptography
https://en.wikipedia.org/wiki/Elliptic_Curve_Digital_Signature_Algorithm
https://en.bitcoin.it/wiki/Secp256k1
https://en.wikipedia.org/wiki/Schnorr_signature
https://en.wikipedia.org/wiki/Curve25519

This site offers some interesting comparisons although some of the conclusions (such as those on Secp256k1) may be controversial:
http://safecurves.cr.yp.to/

This should make bitcoin users feel better:

I believe that the ECC/NSA thread you referenced did eventually nail down every parameter used to create secp256k1 and answers most if not all concerns.
Yes, There is a python script that produces every parameter for secp256k1 from first principles, except the generator— and both myself and D. J. Bernstein have given the proof that in-advance choice of the generator is harmless outside of restricted conditions that aren't relevant to normal Bitcoin usage.

I have been asked in a PM if I would like to comment on this. I am not an expert and have no formal training in algebraic abstract math. Everything I know about this particular field (and cryptography in general) is self-taught mostly in 2014 and 2015. And I have big gaps in my understanding which can only be resolved by teaching myself the higher math courses I didn't take at the university and I don't have time for attaining that base knowledge. Nevertheless I can comment conceptually and understand enough to have for example combined Cryptonote with Compact Confidential Transactions to form what I named Zero Knowledge Transactions. And I understand enough to have digested Shen-noether's Ring Confidential white paper over a period of a day or few days. And I was able to analyze the differences and similarities and ramifications of the high level differences in our approach. So with that in mind, I will comment on the above quoted issue.

Afaik, the main difference between the Secp256k1 type of ECC that Bitcoin uses and the Ed25519 Berstein version of the twisted Edwards curve that Cryptonote uses, is that Ed25519 has no branching in the code and thus has no timing attacks (although one might reason that timing attacks might be less useful in crypto currency, I am not sure if that is true in all scenarios). And (perhaps more importantly) Ed25519 does not require a new random number on each subsequent signature, thus is deemed to less vulnerable to a faulty random number generator (or injection of virus thereof in the operating system). Also Ed25519 is moderately faster and has a prime order which is deemed to more secure (I don't remember if Secp256k1 has a prime order or not).

http://ed25519.cr.yp.to/

So Secp256k1 is probably secure but Ed25519 is more secure.

Please feel free to quote me and claim it as an advantage for Cryptonote coins, but please acknowledge that I have also criticized Cryptonote for not solving the fundamental block chain Tragedy of the Commons economic issues and my opinion that metadata correlation makes their anonymity impractical for any (or most?) mainstream uses.

Thank you for the Secp256k1 vs Ed25519 comparison. I see that ArticMine has been debating with you in the Monero thread about the Tragedy of the Commons issue. Based on my understanding he feels that the tail emission of CryptoNote coins (such as implemented by Monero) are critical to avoiding this and that coins like Boolberry eventually be vulnerable unless a tail emission is added. I agree with ArticMine that a tail emission would help Boolberry but still think we have plenty of time to decide how to implement it based on the BBR emission schedule.

Your objection seems to be centered around the assumption that mining will eventually become centralized (due to cost of electricity and other factors giving some parties a comparative advantage).  I look forward to seeing how future developments (such as smart mining being developed by Monero) and other changes impact decentralization.