how to serializ assetsbundle name string to cache folder names?

Questions & Answers
1

how to serializ assetsbundle name string to cache folder names?
for example:

Cube.prefab.unity3d

version 1 to ac68c7c16a20c60b38daf0b302aa25db6d558e93

version 2 to 4fbae73ca0ffc3af8547e6449bbcf949a023f877

any help?
2

if you user WWW.LoadFromCacheOrDownload API, you will find these cache files in you pc
c:/users/username/appdata/locallow/unity/weplayer/cache/yourapp/

what I want to ask is how to serializ WWW.LoadFromCacheOrDownload(url,version)
to some string like 4fbae73ca0ffc3af8547e6449bbcf949a023f877
it’s seem like some sha-1 format ,but don’t know the detail of that .