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
