Homepage » File Sharing » DC++ » Frequently Asked Questions
DC++

DC++ FAQ

by DC++

What is TTH (Tiger Tree Hashing) ?

Tiger Tree Hashing (TTH) is used to verify the integrity of large chunks of data. The data is split into small pieces which are individually hashed, then hashed together until one root hash is formed. A TTH looks something like:4NIABZVGR4HOTNRPOMH2IRIJQSJYKFHEEIQUJWY.

DC++ 0.400 introduced mandatory TTH. Once DC++ hashes all of your share (yes, this will take a while), it will only hash new files. The hashing thread in DC++ is set to low priority, so it shouldn't interfere too badly.

There are several benefits of file hashing:

* No longer does one need to pay attention to the name of the file when looking for alternative sources. If the files are the same, they will have the same hash and can thus be chosen as an alternative source. Just because two files are the exact same size does not mean they are the same bitwise!

* Magnet Links. Implemented in DC++ 0.4032.

* Segmented (aka multisource) downloading. While it is not currently officially implemented, there is now a safe way to implement downloading files from multiple sources. All clients at this point have been implementing segmented downloading in cowboy fashion. They do not verify that the files are the same (except for the size and partial name), which can result in corrupt files. A file hash ensures the files are identical.