Shparlinski

Le Jeudi 25 Janvier 2001 à 14h30

à l'École Polytechnique (salle de réunion du LIX)

I. Shparlinski

(Department of Computing, Macquarie University, Sydney)

Bit security of Diffie-Hellman and other related schemes

Résumé/Abstract :

I outline an approach proposed by Boneh and Venkatesan to proving that last (log p)1/2 bits of the Diffie-Hellman key gxy mod p are as secure as the whole key. Unfortunately their paper has an error. I will show how to correct this error and outline some other applications. (Joint work with Isabel Gonzales Vasco.)

On the other hand I will show that the same approach can be used to design an attack on DSA and other similar signature schemes. (Joint work with Phong Nguyen.)

These results are based on lattice reduction techniques and, surprisingly enough on some new bounds of exponential sums.