Here's an example. Suppose the block size is 900 bytes (i.e., you
either specified --block-size=900 or saw blength=900 in the output).
Then you could use the following command to overwrite blocks 40 through
45 of the file (counting from 0) with zeros:
dd bs=900 if=/dev/zero of=/home/test.xyz
On Tue 27 Jan 2009, David de Lama wrote:
Then I wanted to overwrite 25 blocks:
dd bs=1M if=/dev/urandom of=/home/test.xyz seek=50 count=25
But when I look at the file, its size is now 76.8MB! So all the Blocks after
block 75 are deleted! :(
Need help, please!
Try the dd manpage, which
-Ursprüngliche Nachricht-
Von: Paul Slootman paul+rs...@wurtel.net
Gesendet: 27.01.09 11:25:31
An: rsync@lists.samba.org
Betreff: Re: Chance of equal checksum and changing blocks
On Tue 27 Jan 2009, David de Lama wrote:
Then I wanted to overwrite 25 blocks:
dd bs=1M if=/dev/urandom
On 22.01.2009 10:43, David de Lama wrote:
Hi @all!
I have two questions:
- First, am I right that the chance of getting the same 32-bit rolling
checksum is 1/2^16 and to get the same 128-bit MD5 Hash is 1/2^127?
No.
The chance of accidental collision with MD5 is: 1/2^64
The other half of
David, please CC rsync@lists.samba.org in your replies so that others
can help you and your messages are archived for others' future benefit.
On Fri, 2009-01-23 at 09:02 +0100, David de Lama wrote:
- Finally I want two know if it is possible to change an amount of
blocks manually?
e.g. I
Hi @all!
I have two questions:
- First, am I right that the chance of getting the same 32-bit rolling checksum
is 1/2^16 and to get the same 128-bit MD5 Hash is 1/2^127?
- Finally I want two know if it is possible to change an amount of blocks
manually?
e.g. I made a 100 MB file with dd
On Thu, 2009-01-22 at 10:43 +0100, David de Lama wrote:
- First, am I right that the chance of getting the same 32-bit rolling
checksum is 1/2^16 and to get the same 128-bit MD5 Hash is 1/2^127?
You might know something I don't, but I would expect the collision
probability to be 1/2^32 for 32
On 22-Jan-2009, at 02:43, David de Lama wrote:
Hi @all!
I have two questions:
- First, am I right that the chance of getting the same 32-bit
rolling checksum is 1/2^16
Depends on the algorithm. Most 32bit algorithms are not really 1:
(2^16)-1
and to get the same 128-bit MD5 Hash is
