How alfresco convert the uploaded documents into bin file?

[jspr]

Hello, I have a question, I think it is strange that when you upload a document in alfresco, it become a bin file but it take the same space than the original document, and when you change the bin extension by its original extension you can open it normally.
Can anyone explain me how alfresco convert the documents or if it just change the extension (and if it is the case why)?

Thanks

[angelborroy]

Just change every extension to ".bin" and the name to "uuid".

Contain remains the same.