[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
ERS - using hash tree?
- To: ietf-ltans@xxxxxxx
- Subject: ERS - using hash tree?
- From: "Jesus Maria Mendez Perez" <jesusmmp@xxxxxxxxx>
- Date: Thu, 22 Nov 2007 18:48:21 +0100
- Dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=beta; h=domainkey-signature:received:received:message-id:date:from:to:subject:mime-version:content-type:content-transfer-encoding:content-disposition; bh=mmk/WOOeRGKUTn7gJCkF6Y95XRuJZuzq/HY4uu4+jEY=; b=HkQdqRHcvG2jAfjfSX+6IeBUTs98thf4jU/Xoc6ya/8pXMKL72Kdueo3yVBRGEwQqKCE9Nq5oyl4MJ4V03hKL7Ny88UIE9uXmWzXT8qQu37fPkAcKq7V+KiFGIju87UblOEELJR2Fe+YTifFTId+97J6+oH/9C5JdWd1vK98IzY=
- Domainkey-signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:message-id:date:from:to:subject:mime-version:content-type:content-transfer-encoding:content-disposition; b=fpRkS3YFlhWIfXoqcy+K+vvhMJmTcKhPTa1OkW2wYZkqi/NcTOpAcBkSg5QHyNc6vRZ8JMxJwZMiGaawKPjte78HrKPEYQ4oFJsmRh5wluctY1BbjZzmDLdVYMXW8CEl+JTXddIjI+lTMI3+kApou5DPXUUOpBqcMTslqCYbQ8o=
- List-archive: <http://www.imc.org/ietf-ltans/mail-archive/>
- List-id: <ietf-ltans.imc.org>
- List-unsubscribe: <mailto:ietf-ltans-request@imc.org?body=unsubscribe>
- Sender: owner-ietf-ltans@xxxxxxxxxxxx
Hello,
IŽm Jesus and I donŽt understand some aspects about using the
hash-tree to preserving data objects.
According to ERS if you have 4 data objects the working will be the next one:
------ ------ ------ ------
| d1 | | d2 | | d3 | | d4 |
------ ------ ------ ------
| | | |
| | | |
------ ------ ------ ------
| h1 | | h2 | | h3 | | h4 |
------ ------ ------ ------
| | | |
| | | |
| |
-------- ------
| h12 | | h34 |
-------- ------
| |
| |
|
-----------
| h1234 |
-----------
|
--------------
| TSh1234 |
--------------
where "d" are the data objects and "h" are the hash of the data
objects and "TS" is the timestamp.
In this case youŽll have to do 7 hashes and the additional timestamping.
Then, what is the meaning of building the hash tree if you really
after of building it you canŽt add or remove any data object?.
You can simply add the 4 hashes of the 4 data objects and do the finish hash.
Then weŽll have to do 5 hashes and the additonal timestamping versus 7
hashes we had before.
------ ------ ------ ------
| d1 | | d2 | | d3 | | d4 |
------ ------ ------ ------
| | | |
| | | |
------ ------ ------ ------
| h1 | + | h2 | + | h3 | + | h4 |
------ ------ ------ ------
| | | |
| | | |
| | | |
-------------------------
| h1234 |
-------------------------
|
----------------------------
| TSh1234 |
---------------------------
I dont know if we could do it this last way or if i donŽt understand
the processing of Generation and Verification at all..
Thanks.