First, tiger is a hash algorythm just like md5 or sha1. "tree" describes a way of using that algorythm where segments of the file are hashed individually. The tigertree implementation used by Bitzi uses 1024b blocks (though they could use any size). I have no evidence but I think that around 1mb would be the best.

The tree hash is the best way to share partial files. A tree hash can use any hash algorithm (ie, md5, sha1, tiger, ect). Small chunks of the file are individually hashed and all of these hashes make up the tree hash. Because of this you could set it so that there is a hash for every 1mb of the file. Then you could securely and confidently download partial files of 1mb size from multiple hosts with partial files.



An added bonus of the tree hash method is the ability to resume from nearly identical files.

For example:

I want to download songx, so I search for it and find it. There are quite a few versions with the same size, bitrate, ect but they have different metadata so the hash is different.

Well, with the tree hash you could use all of those sources to swarm from for the parts of the file that are the same!!! This would greatly increase swarming speeds while providing the same security and confidence we currently have with hashed files!