Ari Singer

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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 sufficient to achieve provable security with existing CCA2-secure schemes. On a positive note, we introduce NAEP, an efficient(More)
NTRUEncrypt is unusual among public-key cryptosystems in that, with standard parameters, validly generated ciphertexts can fail to decrypt. This affects the provable security properties of a cryptosystem, as it limits the ability to build a simulator in the random oracle model without knowledge of the private key. We demonstrate attacks which use decryption(More)
We introduce the concept of Modified Parameter Attacks, a natural extension of the idea of Adapative Chosen Ciphertext Attacks (CCA2) under which some CCA2 secure systems can be shown to be insecure. These insecurities can be addressed at the application level, but can also be addressed when cryptographic schemes are being designed. We survey some existing(More)
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