SEMINAR ANNOUNCEMENT
              CENTER FOR SECURE INFORMATION SYSTEMS
                     GEORGE MASON UNIVERSITY
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              Date :  Thursday, April 19, 2012
              Time :  11:00 - 12:00
          Location :  Research Hall, Room 401
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Recoverable Encryption through Noised Secret over Large Cloud 

Professor Witold Litwin
Université Paris Dauphine, Lamsade

Encryption key safety is the Achilles’ heel of modern cryptography. Simple
backup 
copies offset the risk of key loss, but increase the danger of disclosure,
including 
at the escrow’s site. Recoverable Encryption (RE) alleviates the dilemma.
The 
backup is specifically encrypted so that recovery by brute force, i.e.,
without any 
hint from the key owner remains intentionally cumbersome but feasible. We 
propose RE using so-called noised secret. To dissuade indelicate attempts,
the 
owner sets up the decryption complexity so that recovery at the escrow’s
facility, 
a computer or perhaps a cluster, becomes inhibitive. The actual recovery
fits the 
time desired by the requestor, provided the use of a large cloud. A 10K-node

cloud may suffice to recover the key in ten minutes, for the dissuasive set
up of 
seventy days at an escrow’s a computer.  Large public clouds are now
available 
with acceptable price tags. An illegal use of such a huge resource is
unlikely.  We 
show feasibility of our schemes and their practical potential.

**Point of contact:  Prof Sushil Jajodia [log in to unmask]
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