TY  - INPR
A1  - Schnorr, Claus Peter
A1  - Jakobsson, Markus
T1  - Security of signed ELGamal encryption
N2  - Assuming a cryptographically strong cyclic group G of prime order q and a random hash function H, we show that ElGamal encryption with an added Schnorr signature is secure against the adaptive chosen ciphertext attack, in which an attacker can freely use a decryption oracle except for the target ciphertext. We also prove security against the novel one-more-decyption attack. Our security proofs are in a new model, corresponding to a combination of two previously introduced models, the Random Oracle model and the Generic model. The security extends to the distributed threshold version of the scheme. Moreover, we propose a very practical scheme for private information retrieval that is based on blind decryption of ElGamal ciphertexts.
Y1  - 2005
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/4255
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30-12257
SN  - 3-540-41404-5
N1  - Preprint, später in: Advances in cryptology, 2000, Lecture notes in computer science, Vol. 1976, S. 73-89
SP  - 73
EP  - 89
PB  - Springer
CY  - Berlin [u.a.]
ER  -