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Description: 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...

Tags: basics ,