About PGP Signing a File.

[Tony Arnold]

Matthew Flaschen wrote:
> Joel Bryan Juliano wrote:
>> Hi,
>>
>>  I have a question regarding signing a file or binary, I installed
>> Seahorse which is really awesome tool! And it has a nautilus-extension
>> that easily Encrypt and Sign a file or directory by right-clicking the
>> file. Can someone please tell me the use of signing a binary file or
>> directory? I know it's important, but I really don't get it.
> 
> There's no use, unless you're planning on sending the file to someone.
> If you do send it to someone, they can check the signature to verify you
> sent it.  Emails and most forms of electronic communication can be
> easily forged, but signatures can't be.

Verifying the signature also confirms that the file has not been
modified since you signed it but some malicious person. So it acts a bit
like an MD5 checksum with the added benefit that you can check who
signed it.

Regards,
Tony.
-- 
Tony Arnold, IT Security Coordinator, University of Manchester,
IT Services Division, Kilburn Building, Oxford Road, Manchester M13 9PL.
T: +44 (0)161 275 6093, F: +44 (0)870 136 1004, M: +44 (0)773 330 0039
E: tony.arnold at manchester.ac.uk, H: http://www.man.ac.uk/Tony.Arnold