[bittorrent] Why are blocks smaller than pieces?
tanuki64 at gmx.de
Sat Sep 8 17:38:41 EDT 2007
sorry if this has been answered 100 times. In the archive I could not find
something about my problem. I am currently working to understand the bittorrent
protocol. When I learned that the smallest fraction of data is not actually a
piece, but a block and there can be several blocks in a piece, I wondered if
this isn't a weakness, which can be exploited by malignant clients.
I know cases from emule, where such clients on purpose sent corrupt pieces. Since
in emule every single pieces can be hashed, it is no problem to identify those
clients and block them.
In bittorrent I cannot hash a single block. A client, which sends corrupt blocks
cannot be identified without tremendous efforts. If I wanted to disrupt someones
download I'd modify a client that for every piece it sends one corrupt block.
Are there provisions to protect onself against such a denial of service?
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