Re: Partial transfer of rsyncrypto encrypted files

[Shachar S. <sh...@sh...>]

Jan Alphenaar wrote:
>
> Julian,
>
>  
>
> Both scenario's you describe are the way rsync should behave, but it 
> does not. Let me just describe how case a can be reproduced.
>
>  
>
> Take a large zip file, my file is now 100MB, and encrypt it with 
> rsyncrypto. Now rename that file to 1.zip. Encrypt this file again and 
> rename the encrypted file to 2.zip. Both files should be the same 
> (except the first blocks), right ?
>
That really depends on whether you encrypted them using the same session 
key.
>
>
> Hope it is a bit more clear now.
>
>  
>
> Regards,
>
>  
>
> Jan
>


Here is what I'm testing.

> dd if=/dev/urandom of=/tmp/test bs=$((1024*1024)) count=100

Create a 100MB random file.

> sun@sunlap:/tmp$ rsyncrypto test test1.enc test.key 
> /usr/share/doc/rsyncrypto/examples/tests/cert.crt
> sun@sunlap:/tmp$ rsyncrypto test test2.enc test.key 
> /usr/share/doc/rsyncrypto/examples/tests/cert.crt
Create two files which are (almost) identical. vbindiff confirms this - 
the two files have a different header, but several bytes into the file 
they become identical and remain so until the end of the file.

If this is your situation, rsyncrypto is working as advertised. If rsync 
does not do the expected thing with this case (for example, because it 
does not apply the rsync algorithm to files that start off differently 
but become identical in cases of partial transfers), then this is a 
rsync bug, and has nothing to do with rsyncrypto.

Shachar

-- 
Shachar Shemesh
Lingnu Open Source Consulting Ltd.
http://www.lingnu.com