Paper 2010/135 Original: eprint.iacr.org/2010/135 ↗

On The Broadcast and Validity-Checking Security of PKCS \#1 v1.5 Encryption

Aurélie Bauer
Jean-Sébastien Coron
David Naccache
Mehdi Tibouchi
Damien Vergnaud
Abstract

This paper describes new attacks on PKCS \#1 v1.5, a deprecated but still widely used RSA encryption standard. The first cryptanalysis is a broadcast attack, allowing the opponent to reveal an identical plaintext sent to different recipients. This is nontrivial because different randomizers are used for different encryptions (in other words, plaintexts coincide only partially). The second attack predicts, using a single query to a validity checking oracle, which of two chosen plaintexts corresponds to a challenge ciphertext. The attack's success odds are very high. The two new attacks rely on different mathematical tools and underline the need to accelerate the phase out of PKCS \#1 v1.5.

Metadata
Available format(s)
PDF
Category
Public-key cryptography
Publication info
Preprint.
History
2010-04-14: last updated
2010-03-12: published
Short URL
https://ia.cr/2010/135
License
https://creativecommons.org/licenses/by/4.0/

BibTeX

@misc{cryptoeprint:2010/135,
      author = {Aurélie Bauer and Jean-Sébastien Coron and David Naccache and Mehdi Tibouchi and Damien Vergnaud},
      title = {On The Broadcast and Validity-Checking Security of PKCS \#1 v1.5 Encryption},
      howpublished = {Cryptology {ePrint} Archive, Paper 2010/135},
      year = {2010},
      url = {https://eprint.iacr.org/2010/135}
}
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