1. ISEP / Fakulta Elektrotecknika 1 Project Of Telecommunication Subject: Describe following “ MAC - Message Authentication Code " modes: Describe following “ MAC - Message Authentication Code " modes: MAC, CBC-MAC, HMAC, OMACv1, OMACv2, PMAC Hakim Roqai ChaouiRaphael Morel

2. ISEP / Fakulta Elektrotecknika2 The choice of the subject Cryptography is an interdisciplinary subject present on several fields Cryptography is an interdisciplinary subject present on several fields It is the main tool used in computer and network security for such things as access control and information confidentiality It is the main tool used in computer and network security for such things as access control and information confidentiality It finds many applications that touch everyday life: the security of ATM cards, computer passwords … It finds many applications that touch everyday life: the security of ATM cards, computer passwords …

3. ISEP / Fakulta Elektrotecknika3 The choice of the subject It seems to be interessant to learn: - a new method of cryptography like the MAC algorithms - block cipher algorithms like OMAC, CBC-MAC and PMAC - block cipher algorithms like OMAC, CBC-MAC and PMAC - cryptographic hash functions like HMAC

4. ISEP / Fakulta Elektrotecknika4 How do we proceed? First we used internet in order to know what the project dealt with. Our sources were from Google, wikipedia and other universities internet sites First we used internet in order to know what the project dealt with. Our sources were from Google, wikipedia and other universities internet sites After that, we focused on the real subject and began to understand the different methods of cryptography After that, we focused on the real subject and began to understand the different methods of cryptography And finally we made the final report And finally we made the final report

5. ISEP / Fakulta Elektrotecknika5 What we have learnt MAC is a short piece of information used to authenticate a message MAC is a short piece of information used to authenticate a message A MAC algorithm accepts as input a secret key and an arbitrary-length message to be authenticated, and outputs a MAC (sometimes known as a tag) A MAC algorithm accepts as input a secret key and an arbitrary-length message to be authenticated, and outputs a MAC (sometimes known as a tag) The sender and the receiver of the message must have the same key The sender and the receiver of the message must have the same key

6. ISEP / Fakulta Elektrotecknika6 What is a block cipher ? A block cipher consists of two paired algorithms, one for encryption, E, and another for decryption, E-1 A block cipher consists of two paired algorithms, one for encryption, E, and another for decryption, E-1 Both algorithms accept two inputs: an input block of size n bits and a key of size k bits, yielding an n-bit output block Both algorithms accept two inputs: an input block of size n bits and a key of size k bits, yielding an n-bit output block For any one fixed key, decryption is the Inverse function of encryption, so that For any one fixed key, decryption is the Inverse function of encryption, so that

7. ISEP / Fakulta Elektrotecknika7 What is a block cipher ? Encryption: Decryption:

8. ISEP / Fakulta Elektrotecknika8 Block cipher algorithms OMAC, CBC-MAC and PMAC use block ciphers mode to create a message authentication code OMAC, CBC-MAC and PMAC use block ciphers mode to create a message authentication code They can save code space in very tiny embedded systems like for instance smart cards or nodes in cars They can save code space in very tiny embedded systems like for instance smart cards or nodes in cars

9. ISEP / Fakulta Elektrotecknika9 What is a cryptographic hash function ? In cryptography, a cryptographic hash function is a hash function with certain additional security properties  to make it suitable for use as a primitive in various information security applications, such as authentication and message integrity

10. ISEP / Fakulta Elektrotecknika10 What is a cryptographic hash function ? A hash function takes a long string (or message) of any length as input and produces a fixed length string as output

11. ISEP / Fakulta Elektrotecknika11 HMAC:keyed-hash message authentication code HMAC is a type of MAC calculated using a cryptographic hash function in combination with a secret key HMAC is a type of MAC calculated using a cryptographic hash function in combination with a secret key HMAC may be used to simultaneously verify both the data integrity and the authenticity of a message HMAC may be used to simultaneously verify both the data integrity and the authenticity of a message The cryptographic strength of the HMAC depends upon the cryptographic strength of the underlying hash function and on the size and quality of the key The cryptographic strength of the HMAC depends upon the cryptographic strength of the underlying hash function and on the size and quality of the key

12. ISEP / Fakulta Elektrotecknika12 Conclusion We lost time on “ Mac address ” instead of MAC – Message Authentication Code We lost time on “ Mac address ” instead of MAC – Message Authentication Code Difficulty to make research in English Difficulty to make research in English We enjoyed to discover codes we have never learnt We enjoyed to discover codes we have never learnt Both works at the university and at home Both works at the university and at home Thank you for your hospitality and your happiness Thank you for your hospitality and your happiness