Deniable Encryption Key

Abstract

Deniable encryption is an important that allows a user (a sender and/or a receiver) to escape a coercion attempted by a coercive adversary. Such an adversary approaches the coerced user after transmission forcing him to reveal all his random inputs used during encryption or decryption. Since traditional encryption schemes commit the user to his random inputs, the user is forced to reveal the true values of all his random inputs (including the encrypted/decrypted messages and the encryption/decryption keys) which are verifiable by this coercer using the intercepted cipher text. In this scenario, a coercer may force the user to perform actions against his wish. An appealing property in the mediated RSA, PKI was introduced that, the user has no information, neither about his full private (decryption) key, nor the factorization of the RSA public modulus, which represents an excellent step toward achieving in forcibility in public key encryption, since, a coercer cannot ask the user to reveal such unknown information. In this pa- per we present a scheme for receiver-deniable public-key encryption, by which, the receiver is able to lie about the decrypted message to a coercer and hence, escape a coercion. On one hand, the receiver is able to decrypt for the correct message, on the other hand, all the information held by the receiver, when opened to a coercer, do not allow this coercer to verify the encrypted message and consequently, approaching this user becomes useless from the very beginning.