分野別セミナー

In public key encryption systems, public keys (encryption keys) can
be considered as encryption policies which describe who can decrypt the ciphertext,
and private keys (decryption keys) can be regarded as decryption roles.
We present a general encryption model with partial order delegation
ability, which is a generalized extension for hierarchical identity-
based encryption, broadcast encryption and delegatable functional
encryption, etc. We also construct a concrete anonymous encryption
scheme with constant-size ciphertext which may perform key derivation
with partial-order subset delegation functionality, and prove its
security in the standard model including semantic security, anonymity,
and delegation indistinguishability. We give some practical application
scenarios and deployments for our scheme.
We will present this paper in ProvSec2011.