Symmetric Key Cryptography

Symmetric-key algorithms are a class of algorithms for cryptography that use trivially related, often identical, cryptographic keys for both decryption and encryption. In symmetric key cryptography the encryption key and decryption keys are either same are easily derivable from each other. Other terms for symmetric-key encryption are secret-key, single-key, shared-key, one-key encryption.

This video talks about the way alice and bob can talk with each other over the publicly shared medium but in such a way so that no one should be able to make out the actual conversion. Symmetric key cryptography make use of following algorithm.

• Alice and Bob agree on cryptosystem
• Alice and Bob exchange the key in secretly
• Alice encrypts her plain text message with the decided key and sends it to Bob.
• Bob decrypts the message with the key to get the plains text again

In the later part of the video, I talk more about the challenges faced by symmetric key cryptography and possible attacks on symmetric key cryptography like key maintenance, key distribution, number of keys goes up drastically if involving parties increases etc.

I will be uploading public key cryptography video shortly...

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Amit Vartak, 27 is working in wired and wireless security fields since last 3-4 years. His current area of interest includes IEEE 802.11 (Wi-Fi) suite of protocols, vulnerabilities in these protocols and countermeasure for those vulnerabilities. Working on cutting edge tools and technology always keeps him busy. He has contributed from concept level to final prototyping for the presentations in Defcon 2007 (The Emperor Has No Cloak - WEP Cloaking Exposed) and Toorcon 2007 (Caffe latte attack). He holds 2 patents with USPTO (current status: Patent Pending) and a few papers in IEEE journals on wireless protocol vulnerabilities. Prior to this, he was working on MEMS (Micro Electro Mechanical Systems) and has published a few papers in SPIE and ICMAT. (Yeah… kindda orthogonal fields… but technology really doesn’t limit the talent :) He did his masters in Electrical Engineering from one of the premier institutes in India, Indian Institute of Technology, Bombay (IIT-Bombay) and his under graduation, from University of Mumbai in Electronics and Telecommunication Engineering. He is currently working with AirTight Networks Inc. as a team lead in technology group since last 3 years.You can get in touch with him at amitcv[at]gmail[dot]com