Topic: Cryptonote coin analysis (Read 5508 times)

Question is impossible, because it is linear.

It cannot be explained simply.

what's the difference between CryptoNight and Wild Keccak algos in layman's terms?

Let's open hash-function discussion friends.
Just want to uncover our approach and show differences with CryptoNote that we use in our project announced here: https://bitcointalksearch.org/topic/bbr-boolberry-privacy-and-security-guaranteed-since-2014-577267

First of all I want to say that CryptoNote hash function (so called cn_slow_hash) is actually a very strong protected from ASIC's with different CPU instructions set as well as memory consuming algo. cn_slow_hash works hard on 2MB scratchpad and most of this scratchpad are fits in CPU cache.

For now it is difficult imagine that will be possible to make some specific hardware which will be more effective than CPU and will coast less than CPU. But world changes so fast, nobody knows what will happen in near future. We've all seen how rapid technological breakthroughs capable of performing the computer industry. 

Since cn_slow_hash created 2MB scratchpad, it's have to cover all this data, that's why they use 2²⁰ iterations, and side-effect from this pretty slow work (about 500ms on normal laptop, twice faster on normal pc with suitable cpu cache). It may slow down synchronisation process at downloading blockchain (that is not a big problem) and theoretically it may be possible to attack network - connect and send a random block to make peer calculate slow_hash for useless fake block.

So, putting all together, we want to have:
1. Wide CPU instruction set
2. Memory-oriented algo
3. Small work time.

Realizing it, we've  tried to take a step to the side.

Idea of using blockchain data as scratchpad resulted in this hash function:



Actually this is a keccak hybrid, which use external scratchpad. After each keccack round, psudo-randomly addressed[state vector used as addresses] data is taken from scratchpad and xored with state.
Calculating each block PoW usualy hits about 1100 randomly addressed reading of blocks by 32 bytes.

I used "performance_tests" with different scratchpad size to find out memory hardness:


As you can see, working on small amount of memory 100000 hash operations takes 3020 ms, meanwhile work on 100Mb scratchpad with the same operations count takes 8574 ms.
Such difference(caused by the cache memory overflow) points to real memory hardness we guess.

Wellcome to comment.

Boolberry.

Which of the cryptonote coins has the most hash rate at the moment?

Why would it not be linear?

In comparison to Zerocash, darkcoin etc (take bytecoin ref as Cryptonote in general) = https://forum.cryptonote.org/viewtopic.php?f=2&t=18

I'm personally still trying to find information on cryptonote bloat and scalability.  Most people claim it's an unscalable solution.

This is a lie. CryptoNote whitepaper was published on late 2013. So there is no way Bytecoin can be launched 2 years ago. Bytecoin is premined 80% and the dev pretend that it was "fairly" launched 2 years ago. Monero is released to fix BCN problem, a fair launch.

Re: Cryptonote's scalability
Postby Maurice.P » Tue Apr 01, 2014 7:07 pm

I can add that we're pretty sure that the complexity level won't grow exponentially, so the coin should keep going even when the number of users is high. Once again, Bytecoin has been doing pretty good for the last years. I don't know the current figures, but I'd say several tens of thousands of active users with continuously ongoing transactions.

This is a lie. CryptoNote whitepaper was published on late 2013. So there is no way Bytecoin can be launched 2 years ago. Bytecoin is premined 80% and the dev pretend that it was "fairly" launched 2 years ago. Monero is released to fix BCN problem, a fair launch.

Bytecoin- With origins claiming a release date as far back as 2 years