A CCA-PKE Secure-Cryptosystem Resilient to Randomness Reset and Secret-Key Leakage

In recent years, several new notions of security have begun receiving consideration for public-key cryptosystems, beyond the standard against adaptive chosen ciphertext attack (CCA2). Among these are randomness reset attacks, in which used encryption is forcibly set to some previous value, and constant secret-key leakage wherein factor a secret key’s bits leaked. terms formal definitions, cast as games between challenger an adversary, joint combination attacks means that adversary has access additional queries under his own choosing along with queries. This implies both decryption processes cryptosystem being tampered this notion. paper, we attempt address problem through two cryptosystems incorporate hash proof system extractor primitives. The first relies on random oracle model secure class adversaries, called non-reversing adversaries. We remove assumption requirement our second cryptosystem, proposed primitive LM lossy functions. These functions allow up M branches collection substantially lose information, allowing use loss information challenge For each present detailed proofs using game-hopping procedure. addition, concrete instantation end paper—which DDH assumption.