>>A worm or trojan whose payload steals people's bitcoins is also plausible, though afaik there haven't been any yet. There have been a couple of these actuall

>>A worm or trojan whose payload steals people's bitcoins is also plausible, though afaik there haven't been any yet. There have been a couple of these actually: http://www.pcworld.com/article/2109000/bitcoinstealing-malware-hidden-in-mt-gox-data-dump-researcher-says.html http://www.pcworld.com/article/2109000/bitcoinstealing-malwa... http://www.computerworld.com/s/article/9244772/Bitcoin_market_price_app_39_Bitcoin_Alarm_39_is_carefully_cloaked_malware http://www.computerworld.com/s/article/9244772/Bitcoin_marke... http://www.coindesk.com/cointhief-mac-malware-steals-bitcoins/ http://www.coindesk.com/cointhief-mac-malware-steals-bitcoin... And the most famous probably, cryptolocker - http://en.wikipedia.org/wiki/CryptoLocker http://en.wikipedia.org/wiki/CryptoLocker ...though this is more a ransom strategy than just out-right theft.