Steve Gordon is an Associate Professor at Sirindhorn International Institute of Technology (SIIT), Thammasat University, Thailand. On his Youtube page, you can find four complete lecture series on Security and Cryptography, IT Security, Data Communications and Networks, and Internet Technologies and Applications.
• Introduction to Cryptography
Christof Paar, a Professor at Ruhr University, Bochum Germany, provides an introduction to modern cryptography in this series of 24 lectures.
• Cryptography and Network Security
Prof. D. Mukhopadhyay, from the Department of Computer Science and Engineering at the Indian Institute of Technology provides a broad introduction to Cryptography and Network security in this series of 41 lectures. Production quality could be better, but the video lectures are substantive in nature.
• Computer System Engineering
This undergraduate course, taught by Prof. Robert Morris and Prof. Samuel Madden from MIT, covers the basics of networking and computer security. The first few lectures are not available. But the units on networking and cryptography are available in full beginning with lecture 9.
• Fundamentals of Computer Networking
This series contains over 30 lectures by Professor Parviz Kermani Department of Electrical & Computer Engineering at Manhattan College, and provides an in depth introduction to the basics of computer networking.
Miscellaneous Video• Whitfield Diffie on the History of Public Key Cryptography
• Google Tech Talks on Cryptography (Assorted lectures and seminars from the Google Tech Talk series relating to cryptography and computer security)
• Intro to Network Scanning (Basic introduction to network scanning tools)
• Intro to Pentesting (10 short tutorials)