Seems like ASICs are measured in the thousands to tens or hundreds of thousands of MHashes/sec. Whereas powerful GPUs drawing ~1000 Watts don't even break 1000MH/sec. High-end laptop GPUs seem to be in the 10s of MH/sec, a quad-core Atom shows 2MH/sec, and the Galaxy SII comes in at 1.3.
The vast majority of devices connecting to public APs are not going to be high-power systems. Not to mention the time they'll spend connected is unlikely to be 24/7. Even if it was, mining will probably drain batteries pretty quickly. Plus power-saving is likely to be on for mobile devices and reduce peak perf. And if it's just injecting JS, then backgrounded tabs should get much less CPU time. And WebGL/etc. are unlikely to be running in background tabs.
If you assume a device stays connected and open for 1/4 a day, and stays for 3 days on average, and gives you 1MH/sec (seems optimistic, all things considered), 1 million devices compromised a month gives you ~$300 a month. If the assumption is that you can persistently own a machine, then you'd need less machines. But that's going beyond simple JS injection on HTML pages.
Seems like ASICs are measured in the thousands to tens or hundreds of thousands of MHashes/sec. Whereas powerful GPUs drawing ~1000 Watts don't even break 1000MH/sec. High-end laptop GPUs seem to be in the 10s of MH/sec, a quad-core Atom shows 2MH/sec, and the Galaxy SII comes in at 1.3.
The vast majority of devices connecting to public APs are not going to be high-power systems. Not to mention the time they'll spend connected is unlikely to be 24/7. Even if it was, mining will probably drain batteries pretty quickly. Plus power-saving is likely to be on for mobile devices and reduce peak perf. And if it's just injecting JS, then backgrounded tabs should get much less CPU time. And WebGL/etc. are unlikely to be running in background tabs.
If you assume a device stays connected and open for 1/4 a day, and stays for 3 days on average, and gives you 1MH/sec (seems optimistic, all things considered), 1 million devices compromised a month gives you ~$300 a month. If the assumption is that you can persistently own a machine, then you'd need less machines. But that's going beyond simple JS injection on HTML pages.
I used this calculator: http://www.alloscomp.com/bitcoin/calculator