Using files encrypted with Vigenère cipher as examples, we walk through several techniques to start thinking about how cryptographic systems and cryptanalysis works. The Vigenère cipher provides an opportunity to use multiple tools on a challenging but solvable system. Participants are encouraged to follow the demonstration of encrypting a file then uncovering the password. Software written in Python 3 and test files used in the presentation are available at https://github.com/webpwnized/cryptography.

Jeremy works as a security penetration tester, application security consultant, and defect- remediation expert for a multi-national transportation logistics company. Jeremy is the owner of Ellipsis Information Security LLC assisting the community with security services. Also, Jeremy develops the open-source Mutillidae 2.x training environment and teaches on security topics. As Director of Education for the Kentucky ISSA chapter, Jeremy presents on web application pen-testing and remediation along with operating the "webpwnized" YouTube video channel. Jeremy has a Bachelor in Computer Science from Indiana University and is a GIAC-certified Web Application, Mobile and Network Security Penetration Tester.

Recorded at AIDE 2017