I was working on some educational research and I noticed that SHA1 values are normally comprised of Hex characters. Yet many of the file hash values seen on P2P consist of all alphabetical characters and 2-7. I did some research (including this board) and understand there is a difference between SHA1 methods (Base 16 -vs- Base 32) can someone please:

1) Explain the difference in the two SHA1 calculations (is it just a BASE issue? Am I using the correct terminology?)

2) Explain how to generate the P2P like hash of a file (sha1sum in linux only gives Hex)

3) MOST IMPORTANT - can you convert between Base16 and Base32 (assuming I am using correct terminology) WITHOUT the original file, can a BASE32 hash be generated from the Base16 hash value alone and not recalculated from original file? If so how?