Advances in Cryptology - ASIACRYPT’99

Volume 1716 of the series Lecture Notes in Computer Science pp 165-179

Efficient Public-Key Cryptosystems Provably Secure Against Active Adversaries

  • Pascal PaillierAffiliated withGemplus Cryptography DepartmentENST
  • , David PointchevalAffiliated withLIENS – CNRS, École Normale Supérieure


This paper proposes two new public-key cryptosystems semantically secure against adaptive chosen-ciphertext attacks. Inspired from a recently discovered trapdoor technique based on composite-degree residues, our converted encryption schemes are proven, in the random oracle model, secure against active adversaries (NM-CCA2) under the assumptions that the Decision Composite Residuosity and Decision Partial Discrete Logarithms problems are intractable. We make use of specific techniques that differ from Bellare-Rogaway or Fujisaki-Okamoto conversion methods. Our second scheme is specifically designed to be efficient for decryption and could provide an elegant alternative to OAEP.