Notes - Cryptographic Applications

The following are notes from Introduction to Cryptography with Coding Theory.

• 4 main objectives of Cryptography
• Confidentiality
• there should be no eavesdroppers to a message
• Data Integrity
• the messag should not be altered through transmission
• hash functions to detect data manipulation
• Authentication
• Sender wants verification that message was received by the correct person
• identification
• Non-repudiation
• cannot claim that a false message has been sent
• Authentication is closely linked to non-repudiation but there are differences
• In symmetric key encryption, Bob can be sure a message comes from Alice so authentication is automatic but cannot prove to anyone else that Alice sent that message since he could have sent that message himself
• Functions
• Digital Signatures
• link an individual's identity to a message
• Identification
• password protection to identify oneself
• Feige-Fiat-Shamir method of identification zero knowledge based method for proving identity without revealing password
• Key Establishment
• Various ways to pass keys
• public key cryptography
• Diffie-Hellman key exchange algorithm
• Blom's key generation scheme and Kerberos
• Secret Sharing
• divide the key among different individuals so all members must be present to unlock
• Security Protocols
• How we carry out secure transactions
• SSL, SET
• Electronic Cash
• Providing anonymity while catching counterfeiters
• Games
• How to determine fair randomness?

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