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Re:“An on-page advert was mining bitcoin in my browser” by wyldfire on Tuesday August 29, 2017 @10:08AM (#15124347)
The ROI is likely nonzero for some coins out there. Bitcoin's difficulty would be too high to make much money even if the ad were served to a very large number of computers. But other non-SHA coins (CryptoNight-based PoW, e.g.) or low-difficulty coins might be worthwhile.

> Mining bitcoin won't need 40MB of download.

Are you sure? I would think something like cgminer compiled to wasm/asm.js could be a 40MB payload.

For more context, OP states:

> "checked sources and discovered it was a Bitcoin add in iframe, looked at JS it used"

> "It was also an ad for a btc exchange/wallet thing, so maybe the mining was just to recoup some cost?"

The nebulous "sources" referred to might be something credible. I imagine bitcointalk.org may have a thread on malicious ads like this.

Re:“An on-page advert was mining bitcoin in my browser” by LyndsySimon on Tuesday August 29, 2017 @11:03AM (#15124752)
> The ROI is likely nonzero for some coins out there.

If it's more profitable to mine $ARBITRARY_ALT_COIN than Bitcoin, then people would mine $ARBITRARY_ALT_COIN until the profitability equalized.

> Are you sure? I would think something like cgminer compiled to wasm/asm.js could be a 40MB payload.

There's no need for that: https://github.com/jwhitehorn/jsMiner

Re:“An on-page advert was mining bitcoin in my browser” by ringaroundthetx on Tuesday August 29, 2017 @12:51PM (#15125641)
> If it's more profitable to mine $ARBITRARY_ALT_COIN than Bitcoin, then people would mine $ARBITRARY_ALT_COIN until the profitability equalized.

Thats.... what people do.

Market inefficiencies come up predictably because coins have different block reward and emission schedules. They have different algorithms which give advantages to different processors. The market efficiency time sometimes requires a completely new fabrication line created in china, this gives significant times till mining arbitrage goes away.

Similarly, multipool miners have software which automatically switches to different blockchain networks when the yield is favorable.

It is a mistake to think there is no opportunity just because someone told you there are always smarter more observant people profiting off the opportunity.

Re:“An on-page advert was mining bitcoin in my browser” by LyndsySimon on Tuesday August 29, 2017 @01:24PM (#15125939)
> It is a mistake to think there is no opportunity just because someone told you there are always smarter more observant people profiting off the opportunity.

I agree - I'm not denying that there are ever opportunities for arbitrage, I'm merely asserting that there isn't going to be an alt out that there is "significantly" more profitable to mine than Bitcoin itself.

Re:“An on-page advert was mining bitcoin in my browser” by ringaroundthetx on Tuesday August 29, 2017 @02:25PM (#15126473)
Okay

I would still disagree, my first thought was defining significantly. When 300% more profitable are the typical differences in yield, how is that insignificant? So then I decided the logical rebuttal would be "over time", where the assertion would be that it isn't significantly more profitable over time.

The rebuttal to that is that baskets of alt coins outperform bitcoin significantly, again by at least 300% barring the worst luck.

And even in a bad year for alts, it is possible to find a difficulty algorithm that you can game giving you an advantage that nobody else notices.

Re:“An on-page advert was mining bitcoin in my browser” by wyldfire on Tuesday August 29, 2017 @12:22PM (#15125373)
> If it's more profitable to mine $ARBITRARY_ALT_COIN than Bitcoin, then people would mine $ARBITRARY_ALT_COIN until the profitability equalized.

That's a reasonable theory but I don't think it holds. Given that (1) $ARBITRARY_ALT_COIN aren't typically well-known, (2) setting up mining may require different hardware/software to enable computing this PoW, that pool, etc, (3) coins and pools have interesting reward & difficulty adjustment algorithms, some better designed to deter coin-hopping. On some coarse-enough scale the general claim of equalization is reasonable -- the differences will be minimized over time. But I have seen times when you could make 5-10% more by mining $ARBITRARY_ALT_COIN (and perhaps taking the altcoin to exchange for bitcoin).

> There's no need for that: https://github.com/jwhitehorn/jsMiner

shrug, seems like we're on a tangent. This thread was speculating about whether the claim of an ad-served-miner exists. The fact that a small JS miner exists for one PoW doesn't seem to rule out the original claim, nor does it rule out the possibility that a wasm/asm.js cgminer might exist.

Re:“An on-page advert was mining bitcoin in my browser” by LyndsySimon on Tuesday August 29, 2017 @01:28PM (#15125968)
> But I have seen times when you could make 5-10% more by mining $ARBITRARY_ALT_COIN (and perhaps taking the altcoin to exchange for bitcoin).

Right - maybe you could even make 100% more with an alt, for a limited period. My point is that you'd need to be able to make 20000x as much as you could make with Bitcoin before you reach parity with using traditional ads.

> shrug, seems like we're on a tangent. This thread was speculating about whether the claim of an ad-served-miner exists. The fact that a small JS miner exists for one PoW doesn't seem to rule out the original claim, nor does it rule out the possibility that a wasm/asm.js cgminer might exist.

Gotchya. I was just trying to show that giving access to computing resources instead of viewing ads is not currently anywhere close viable.

Re:“An on-page advert was mining bitcoin in my browser” by SparkyMcUnicorn on Tuesday August 29, 2017 @10:12AM (#15124378)
Also, he says "It may have been another currency, I can't be certain. Should have generalised"

https://twitter.com/adamjogrady/status/902533084767072258