AW: Strong encryption

C.Zimmermann clemens at
Wed Jun 5 03:25:08 EST 2002

> If you want them stored on the destination encrypted you

Yes, that´s it. The owner of the source files will be sure, that no one
else can read his files on the destination host.

I thought, rsync only looks at the modification date of a file and
decides whether to backup this file or not. In this case, the backup
could be stored  encrypted.

Bye Clemens

> will need to keep them encrypted on the source.  Rsync won't
> be able to compare an encrypted (cyphertext) file with an 
> unencrypted (plaintext) one.  For rsync to support encryption 
> it would need to be able to decrypt your files and that would 
> be very insecure.
> If you keep the files encrypted on the source and
> destination you might as well use the rsync -w option
> because for encryption to be effective it truly does need to 
> randomize the data rendering the special efficencies of rsync 
> moot.  Additionally, for the class of cyphers you mention to 
> be secure they need long keys that change frequently and are 
> best generated randomly and then encrypted using even more 
> secure cyphers.  This randomness assures that no file will be 
> encrypted to the same cyphertext twice.
> Sorry if i bowled you over on the cyphertext files issues. 
> Hopefully all you needed was a pointer to secure 
> transmission.  If not, a coherent description of why the need 
> for encryption may help us find a way to meet your needs.
> -- 
> ________________________________________________________________
> 	J.W. Schultz            Pegasystems Technologies
> 	email address:		jw at
> 		Remember Cernan and Schmitt

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