[TheEskimo]

I believe that there is an even more important practical issue.

What if someone manages to embed something very much like the EICER string[0] in it? How many people do you think would use the bitcoin client on windows if their AV automatically deleted the blockchain as it downloaded in a misguided attempt to protect them?

Of course, first we have to know if this is possible at all. Does anyone know if there's either a) 20 bytes with a very high AV detection rate or b) some way to embed more than 20 bytes in a row in the block chain?

[0]: http://en.wikipedia.org/wiki/EICAR_test_file

[oleganza]

After a couple of times when AV deletes the blockchain, it will either be uninstalled by the user, or fixed by its developer. Not a big deal.