Chapter 2 Flashcards
What are the essential ingredients of a symmetric cipher?
Plain Text
Encryption algorithm
secret key
cipher text
How many keys are required for two people to communicate via a symmetric cipher?
One
What are the two principal requirements for the secure use of symmetric encryption?
power encryption algorithm
Keep the secret key secure
List three approaches to message authentication.
Authentication with symmetric encryption
Authentication without encryption
Message authentication code (MAC)
Hash function
What is MAC?
Message authentication code – one type of message authentication which ensures the confidentiality of message and provides non-repudiation.
What properties must a hash function have to be useful for message authentication.
applied to a block of data
produces a fixed-length output
relatively easy to computer
What are the principal ingredients of a public-key cryptosystem?
plain text Encryption algorithm Public and private key cipher text decryption algorithm
List and define three uses of a public-key cryptosystem.
Encryption and decryption
Digital signature
Key exchange
What is the difference between a private key and a secret key?
Secret Key is used in symmetric encryption - same key is share between sender and receiver.
private key is used in asymmetric encryption - only the public key is shared.
Digital signature
method used to ensure message authentication and integrity of message.
What is a public-key certificate?
a certificate or document which is used to validate the public key of a user. Consists of the ID of the user, the user’s public key and the digital signature of the CA.
How can public-key encryption be used to distribute a secret key?
Diffie-hellman exchange
RSA (Rivest, Shamir and Adleman) key exchange
