Speaker: Volker Gebhardt (UWS) Title: Braid Groups in Cryptography Time & Place: 3-4pm, Thursday 25 January, Carslaw 535 Abstract: After recalling braid groups and the Garside normal form, I will explain the Diffie-Hellman like key exchange introduced by Ko et al. and some related cryptographic protocols, which are all based on the conjugacy search problem (CSP) in braid groups. In the second part of the talk I will present recent solutions to the CSP and we will see that they yield effective attacks on these cryptographic protocols in their present form. Time permitting, I will finally discuss some possible modifications to the cryptographic protocols, such as appropriate choice of keys or replacing the CSP by the decomposition problem.