A Chosen Ciphertext Attack on RSA Optimal Asymmetric Encryption Padding (OAEP) as Standardized in PKCS #1 v2.0

  • James Manger
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 2139)


An adaptive chosen ciphertext attack against PKCS #1 v2.0 RSA OAEP encryption is described. It recovers the plaintext - not the private key - from a given ciphertext in a little over log2 n queries of an oracle implementing the algorithm, where n is the RSA modulus. The high likelihood of implementations being susceptible to this attack is explained as well as the practicality of the attack. Improvements to the algorithm to defend against the attack are discussed.


chosen ciphertext attack RSA OAEP PKCS 


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    D. Bleichenbacher: Chosen Ciphertext Attacks Against Protocols Based on the RSA Encryption Standard PKCS #1. In Hugo Krawczyk (ed.), Advances in Cryptology-CRYPTO’ 98, pages 1–12, Berlin, Springer, 1998 (Lecture Notes in Computer Science, vol. 1462).CrossRefGoogle Scholar
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    PKCS #1 v2.0: RSA Cryptography Standard, 1 October 1998.
  3. 3.
    PKCS #1 v2.1 draft 2: RSA Cryptography Standard, 5 January 2001.
  4. 4.
    IEEE 1363 draft 13: Standard Specifications for Public Key Cryptography, 12 November 1999.
  5. 5.
    M. Bellare and P. Rogaway: Optimal Asymmetric Encryption Padding — How to Encrypt with RSA. In Advances in Cryptology — EUROCRYPT’ 94, pages 92–111, Springer-Verlag, 1994.Google Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2001

Authors and Affiliations

  • James Manger
    • 1
  1. 1.Telstra Research LaboratoriesMelbourneAustralia

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