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Message authentication code presentation.pptx
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- 2. MESSAGE AUTHENTICATION • Protectingthe Integrity of the message. • Validating identity of originator. • Non-Repudiation of origin METHOD TO PRODUCE AUTHENTICATION • Message Encryption • Message Authentication Code (MAC) • Hash Function
- 3. MESSAGE ENCRYPTION SYMMETRIC MESSAGEENCRYPTION PUBLIC KEY MESSAGE ENCRYPTION
- 4. MESSAGE AUTHENTICATION CODE •We will use a secret key to generate a small fixed size block of data called MAC or Cryptographic checksum. • It is then Appended to message as a signature. • The communicating parties will share secret common key • Receiver performs same computation on message and checks it matches the MAC. • It calculate the MAC as a fn of the message and the key MAC = C(K,M)
- 5. M – Message K– Key M’ – MAC function with secret key SENDER RECEIVE R MESSAGE AUTHENTICATION CODE WITHOUT ENCRYPTION Interne t
- 6. MESSAGE AUTHENTICATION CODEWITH ENCRYPTION SENDER RECEIVE R M – Message K – Key 1 K’ – Key 2 E – Encryption D – Decryption M’ – MAC function with secret key Interne t
- 7. EXTERNAL ERROR CODE SENDERRECEIVE R M – Message K – Key 1 K’ – Key 2 E – Encryption D – Decryption M’ – MAC function with secret key C – Encrypted Message Interne t
- 8. HASH – MESSAGEAUTHENTICATION CODE HMAC (Hash-based Message Authentication Code) is a type of a message authentication code (MAC) that is acquired by executing a cryptographic hash function on the data (that is) to be authenticated and a secret shared key. Like any of the MAC, it is used for both data integrity and authentication. Ipad = 00110110 Opad = 01011100
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