A Forward-Secure Public-Key Encryption Scheme

Cryptographic computations are often carried out on insecure devices for which the threat of key exposure represents a serious concern. Forward security allows one to mitigate the damage caused by exposure of secret keys. In a forward-secure scheme, secret keys are updated at regular periods of time; exposure of the secret key corresponding to a given time period does not enable an adversary to “break” the scheme (in the appropriate sense) for any prior time period. We present the first constructions of (non-interactive) forward-secure public-key encryption schemes. Our main construction achieves security against chosen-plaintext attacks in the standard model, and all parameters of the scheme are poly-logarithmic in the total number of time periods. Some variants and extensions of this scheme are also given. We also introduce the notion of binary tree encryption and construct a binary tree encryption scheme in the standard model. Our construction implies the first (hierarchical)...

• Type: Conference
• Year: 2003
• Where: EUROCRYPT
• Authors: Ran Canetti, Shai Halevi, Jonathan Katz
• Keywords: Cryptography, Encryption Scheme, EUROCRYPT 2003, Secret Key, Time Periods