NAEP: Provable Security in the Presence of Decryption Failures.
Nick Howgrave-Graham, Joseph H. Silverman, Ari Singer, William Whyte · 2003
We consider the impact of the possibility of decryption failures in proofs of security for padding schemes, where these failures are both message and key dependent. We explain that an average case failure analysis is not necessarily su#cient to achieve provable security with existing CCA2-secure schemes. On a positive note, we introduce NAEP, an e#cient padding scheme similar to PSS-E designed especially for the NTRU one-way function. We show that with this padding scheme we can prove security in the presence of decryption failures, under certain explicitly stated assumptions. We also discuss the applicability of proofs of security to instantiated cryptosystems in general, introducing a more practical notion of cost to describe the power of an adversary.