Agreed. But my question outstanding.
On Jan 4, 2006, at 2:18 PM, [EMAIL PROTECTED] wrote:
Shai is perfectly right. Here is another back-of-an-envelope
calculation:
We consider magnetic disks. The smallest domain size physically
capable
of storing magnetic information is about 3nm, 10^-17 m^2. The useable
area of a disk platter is about 50 cm^2 = 5*10^-3 m^2, that is, the
number of bits on a platter cannot be more than 2*10^13. With the
servo
information, error correcting codes, etc. it translates to about 2 TB.
This is a physical limit. You are speaking about 2^64 blocks of 16
bytes each = 2^68 bytes. It takes 2^67/10^12 = 148 million disk
platters to store that much data.
Don't spend our time discussing such unrealistic scenarios.
Laszlo
-------- Original Message --------
Subject: RE: p1619 (disk): Security level of LRW
From: "Shai Halevi" <[EMAIL PROTECTED]>
Date: Wed, January 04, 2006 3:47 am
To: "SISWG" <[EMAIL PROTECTED]>
(I will spare you the back-of-an-envelope
calculation of how long does it take to send 2^64 blocks over
a 100 Gbit/sec link.)
I think this argument is not very relivant. There was a time
when 2^32
block was considered huge and 2^48 blocks was and impossibly
large size.
ok, so I will not spare you the calculation: it takes roughly 550
years
to send 2^64 blocks over a 128 Gbit/sec link. This says nothing
about the
time to compute things or protocol overhead, just the time to move
the
raw bits over the link.
(2^64 * 16 * 8 bits) / (128 * 2^30 bits/sec) =2^34 seconds =544.77
years
-- Shai
