Scalable Key-Escrow
Ivan B. Damgård
May 2003 |
Abstract:
We propose a cryptosystem that has an inherent key escrow
mechanism. This leads us to propose a session based public verifiable key
escrow system that greatly improves the amount of key material the escrow
servers has to keep in order to decrypt an encryption. In our scheme the
servers will only have a single secret sharing, as opposed to a single key
from every escrowed player. This is done while still having the properties:
1) public verifiable: the user proves to everyone that the encryption can
indeed be escrowed, and 2) no secret leakage: no matter how many decryptions
a law enforcement agency is presented, it will gain no more information on
the users private key, than it couldn't have calculated itself
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