G'day,
From: Wayne Davison [EMAIL PROTECTED]
On Thu, Apr 08, 2004 at 03:50:48PM +1000, Donovan Baarda wrote:
I think I've just realised what you were getting at; if the
checksum_seed is based on something like the whole file md4sum, it
becomes repeatable, but unpredictable.
Not so. Copy
Hi,
On 2004/04/05 07:21, Donovan Baarda wrote:
[snip]
there are four ways crafted blocks can be use;
1) two crafted blocks in the original file
2) two crafted blocks in the target file
3) a crafted pair of target and original files with matching
block(s)
4) a block in the target
G'day,
From: Eran Tromer [EMAIL PROTECTED]
[...]
librsync needs a whole file checksum. Without it, it silently fails for
case 1), 3), and 4).
librsync could benefit from a random checksum_seed. It would need to be
included in the signature. Without it librsync is vulnerable to cases 1)
On 2004/04/08 08:50, Donovan Baarda wrote:
In some cases you might prefer to actually store an signed signature
using something like GPG.
I think librsync should act as a black box that guarantees file
integrity (which, apparently, requires a whole file checksum). If
someone wants to add
G'day again,
From: Eran Tromer [EMAIL PROTECTED]
[...]
if the
checksum_seed is based on something like the whole file md4sum, it
becomes repeatable, but unpredictable. You can't manipulate individual
blocks without it affecting every other blocksum, but the signature for
the same file
Ahoy,
On 2004/04/08 14:16, Donovan Baarda wrote:
Nice indeed, but the cost is enormous: you'll have to read the file
twice. When syncing a mostly-unchanged file that's larger than the disk
cache, that means doubling the runtime (and disk load) on the receiver's
side. Also, it means 'rdiff
On Thu, Apr 08, 2004 at 03:50:48PM +1000, Donovan Baarda wrote:
I think I've just realised what you were getting at; if the
checksum_seed is based on something like the whole file md4sum, it
becomes repeatable, but unpredictable.
Not so. Copy the file once, and you'd get all the data you'd
On Thu, 2004-04-08 at 12:36, Martin Pool wrote:
On 5 Apr 2004, Donovan Baarda [EMAIL PROTECTED] wrote:
librsync needs a whole file checksum. Without it, it silently fails for
case 1), 3), and 4).
Yes, a whole-file checksum should be used with it. Presumably
something stronger than md4
G'day again,
Just revisiting an old thread after some more thought. Eran and I were
discussing the vulerability of librsync and rsync to deliberate attempts
to craft blocks with matching signatures but different content. It turns
out it's disturbingly easy. Here's a bit of context;
From: Donovan
