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File ID

Posted: Tue Jun 13, 2006 11:43 am
by Xela
It looks like the most false proof way to recognise the file is the look at File ID, that initial Hex Stamp. I know that FileExt.com has that included in the characteristic and detailed description of each file. However, to make that process of verification faster, perhaps list showing this ID and then file type wold be helpful. Anyone knows if such a list exists, please post the link.

And then therre are those on line file analysers. One here
http://mark0.net/onlinetrid.aspx.
Any others?

I wonder how such a analyzer works? Does it scan just the begining of the file or it searches for the ID string in the body of the file too. Sometimes the searched and recognisable file is burried inside.

Posted: Tue Jun 13, 2006 8:46 pm
by Rahly
this initial hexstamp (signature) isn't always accurate, there are many files which don't include one, or some where its not the in the front. Examples of this are MP3's or JPEGs. Mp3s only have a signature for say "ID2/3" tags, and JPEG's signature is after the first 4 bytes.

But an example of a program like what you posted, is *nix's "file" command. Under linux you can use "man magic" to find more information on how to add more, including the file that stores the "algo" to figure out a file.

example of an entry: ZIP

Code: Select all

# ZIP archives (Greg Roelofs, c/o zip-bugs@wkuvx1.wku.edu)
0 string    PK\003\004  Zip archive data
>4  byte    0x09    \b, at least v0.9 to extract
>4  byte    0x0a    \b, at least v1.0 to extract
>4  byte    0x0b    \b, at least v1.1 to extract
>4  byte    0x14    \b, at least v2.0 to extract

Re: File ID

Posted: Thu Jun 15, 2006 2:06 pm
by MarcoPon
My first post here. I came to know about this forum / site trough Dinoguy1000 and seeing some refereer on my site log.
So Hi! to all! :)
Xela wrote:I wonder how such a analyzer works? Does it scan just the begining of the file or it searches for the ID string in the body of the file too. Sometimes the searched and recognisable file is burried inside.
My TrID does something like that. It both checks for patterns on the header and for specific tokens around the file.

Bye!

Posted: Fri Jun 16, 2006 4:18 am
by Xela
Thank you Marco for popping in and reply.
TRID is 8)

Posted: Sun Jun 18, 2006 1:46 pm
by MarcoPon
Thanks! :)

Bye!