Imperfect forward secrecy

@article{Adrian2019ImperfectFS,
  title={Imperfect forward secrecy},
  author={David Adrian and Karthikeyan Bhargavan and Zakir Durumeric and Pierrick Gaudry and Matthew Green and J. Alex Halderman and Nadia Heninger and Drew Springall and Emmanuel Thom{\'e} and Luke Valenta and Benjamin VanderSloot and Eric Wustrow and Santiago Zanella B{\'e}guelin and Paul Zimmermann},
  journal={Communications of the ACM},
  year={2019},
  volume={62},
  pages={106 - 114}
}
We investigate the security of Diffie-Hellman key exchange as used in popular Internet protocols and find it to be less secure than widely believed. [] Key Method To carry out this attack, we implement the number field sieve discrete logarithm algorithm. After a week-long precomputation for a specified 512-bit group, we can compute arbitrary discrete logarithms in that group in about a minute. We find that 82% of vulnerable servers use a single 512-bit group, and that 8.4% of Alexa Top Million HTTPS sites…

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