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Conference papers
Distributed Public-Key Cryptography from Weak Secrets
Abstract : We introduce the notion of distributed password-based public-key cryptography, where a virtual high-entropy private key is implicitly defined as a concatenation of low-entropy passwords held in separate locations. The users can jointly perform private-key operations by exchanging messages over an arbitrary channel, based on their respective passwords, without ever sharing their passwords or reconstituting the key. Focusing on the case of ElGamal encryption as an example, we start by formally defining ideal functionalities for distributed public-key generation and virtual private-key computation in the UC model. We then construct efficient protocols that securely realize them in either the RO model (for efficiency) or the CRS model (for elegance). We conclude by showing that our distributed protocols generalize to a broad class of « discrete-log »-based public-key cryptosystems, which notably includes identity-based encryption. This opens the door to a powerful extension of IBE with a virtual PKG made of a group of people, each one memorizing a small portion of the master key.
Cited literature [7 references]
https://hal.inria.fr/inria-00419149
Contributor : David Pointcheval <>
Submitted on : Tuesday, September 22, 2009 - 4:22:05 PM
Last modification on : Friday, February 26, 2021 - 9:30:02 AM
Long-term archiving on: : Tuesday, October 16, 2012 - 11:11:21 AM
Contributor : David Pointcheval <>
Submitted on : Tuesday, September 22, 2009 - 4:22:05 PM
Last modification on : Friday, February 26, 2021 - 9:30:02 AM
Long-term archiving on: : Tuesday, October 16, 2012 - 11:11:21 AM
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2009_pkc.pdf
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