5 ms·
The particulars of the BT protocol are beyond me, but I thought it would already do a compare between the copy you had and the one on the external server, and o
by TheCraiggers 13y ago
The particulars of the BT protocol are beyond me, but I thought it would already do a compare between the copy you had and the one on the external server, and only send the relevant bytes to bring everything up to sync again.
Between that and a "compare timestamps to figure out the newest file" I wouldn't think it would be that hard to re-create? What am I missing here?
- Osiris 13y agoBitTorrent creates a hashes of your file. The file is broken down into certain size chunks and hashes taken of each chunk. If you already have a piece with a given hash, you won't download it. If a hash differs, it'll be transmitted. The receiver verifies the hash. If it fails it re-requests that piece. I assume the sync protocol works the same. It hashes the file, checks if any chunks have changed, sends the hash meta-data to the recipient, who then requests and pieces that have changed.
- dman 13y agoWhat about hash collisions?
- tokenizerrr 13y agoSHA-2 has no collisions found as of yet [1]. The collision attacks on md5 required a lot of junk data, so not sure how much of a problem that would be. [1]: https://en.wikipedia.org/wiki/SHA-2#Comparison_of_SHA_functions https://en.wikipedia.org/wiki/SHA-2#Comparison_of_SHA_functi...