The videos in the following lessons explain how bitcoins works and how they are used:
Lesson#2 Proof of Work
Lesson#3 Transaction Block Chains
Lesson#4 Transaction Records
Lesson#5 Cryptographic Hash Function
Lesson#6 Digital Signatures
Lesson#7 The Money Supply
Videos by Zulfikar Ramzan. Zulfikar Ramzan is a world-leading expert in computer security and cryptography and is currently the Chief Scientist at Sourcefire. He received his Ph.D. in computer science from MIT.