Marc Stevens Arjen K. Lenstra Benne de Weger Chosen-Prefix Collisions for MD5 and Colliding X.509 Certificates for Different Identities. 1-22 2007 conf/eurocrypt/2007 EUROCRYPT http://dx.doi.org/10.1007/978-3-540-72540-4_1 db/conf/eurocrypt/eurocrypt2007.html#StevensLW07