Extraction et attaque de clés publiques RSA grâce à une faiblesse courante des signatures électroniques - application à PGP et Vigik

This talk will show a very common weakness in RSA signatures. We will be able to computationally extract public RSA keys from communications and embedded systems in case the public key is voluntarily not published. This weakens RSA signatures where keys of small sizes and/or quality are used and allows direct factoring attacks. 2 studies will be conducted on PGP/GPG e-mails and on the Vigik access control system which protects access to nearly 1 million buildings in France.