Cryptology ePrint Archive: Report 1997/012
Self-Delegation with Controlled Propagation - or - What If You Lose Your Laptop.
Oded Goldreich, Birgit Pfitzmann, and Ronald L. Rivest
Abstract: We introduce delegation schemes wherein a user may delegate rights to
himself, i.e., to other public keys he owns, but may
not safely delegate those rights to others, i.e., to their
public keys. In our motivating application, a user
has a primary (long-term) key that receives rights, such as access
privileges, that may not be delegated to others, yet the user may
reasonably wish to delegate these rights to new
secondary (short-term) keys he creates to use on his laptop when
traveling, to avoid having to store his primary secret key on the
We propose several cryptographic schemes, both generic and practical,
that allow such self-delegation while providing strong motivation for
the user not to delegate rights that he only obtained for personal use
to other parties.
Category / Keywords: Delegation, subkeys, key hierarchy, Zero-Knowledge Proofs, Knowledge Complexity, Threshold Schemes, gradual release of secrets, Signature Schemes, Non-Interactive Zero-Knowledge, Commitment Schemes.
Publication Info: Appeared in the THEORY OF CRYPTOGRAPHY LIBRARY and has been included in the ePrint Archive.
Date: Received September 16th, 1997. Revised May 1998. Revised again August 1998.
Contact author: oded at wisdom weizmann ac il
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