David Perez is founder and security analyst with Taddong. David has more than 10 years of experience in delivering advanced security services to clients in all market sectors, conducting security research projects and teaching courses on security. He is the author of various technical articles, talks and training courses, and co-author of the book "Hacking y seguridad en comunicaciones moviles GSM/GPRS/UMTS". He holds a degree in Telecommunications Engineering and is one of the few individuals who have obtained the GIAC Security Expert (GSE) certification.