This method was already used to bypass the content filter of Napster. There were filename scramblers which encrypted the filenames in a way it could be decrypted if you know the code.

But that ain't work.

On Gnutella we use hash to make sure if you are downloading the correct file. That ensures you that each source you are downloading the file from provides the same file, so it is useful.
SHA1 uniquely identifies a file in a 32 string code, never mind of the filename, as long as the file itself is not edited, the SHA1 remains the same.