International Conference on the Theory and Application of Cryptology and Information Security

ASIACRYPT 2000: Advances in Cryptology — ASIACRYPT 2000 pp 30-43

Why Textbook ElGamal and RSA Encryption Are Insecure

Extended Abstract
  • Dan Boneh
  • Antoine Joux
  • Phong Q. Nguyen
Conference paper

DOI: 10.1007/3-540-44448-3_3

Volume 1976 of the book series Lecture Notes in Computer Science (LNCS)

Abstract

We present an attack on plain ElGamal and plain RSA encryption. The attack shows that without proper preprocessing of the plaintexts, both El Gamal and RSA encryption are fundamentally insecure. Namely, when one uses these systems to encrypt a (short) secret key of a symmetric cipher it is often possible to recover the secret key from the ciphertext. Our results demonstrate that preprocessing messages prior to encryption is an essential part of bothsy stems.

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Copyright information

© Springer-Verlag Berlin Heidelberg 2000

Authors and Affiliations

  • Dan Boneh
    • 1
  • Antoine Joux
    • 2
  • Phong Q. Nguyen
    • 3
  1. 1.Computer Science DepartmentStanford UniversityStanfordUSA
  2. 2.DCSSIIssy-les-Moulineaux CedexFrance
  3. 3.Département d’InformatiqueÉcole Normale SupérieureParisFrance