Network Security - Lecture 22In today’s we explored the limitations of the centralized key distribution and have explored key distribution in a decentralized fashion. Message Authentication Mechanism Message encryption MAC Hash
34 trang | Chia sẻ: dntpro1256 | Ngày: 20/11/2020 | Lượt xem: 609 | Lượt tải: 0
Network Security - Lecture 21In today’s we continued our discussion about Confidentiality using symmetric encryption Key exchange is a challenging task in symmetric key cryptography. We discussed the role of KDC The design constraints for Key Distribution was also explored
24 trang | Chia sẻ: dntpro1256 | Ngày: 20/11/2020 | Lượt xem: 671 | Lượt tải: 0
Network Security - Lecture 20link encryption obscure header details but overall traffic volumes in networks and at end-points is still visible traffic padding can further obscure flows End to end Encryption Application layer: communicating entities are visible Transport layer: network address and traffic patterns are visible Uniform Padding deny an opponent knowledge of ...
23 trang | Chia sẻ: dntpro1256 | Ngày: 20/11/2020 | Lượt xem: 645 | Lượt tải: 0
Network Security - Lecture 19We explored an example of PKC, i.e., RSA. In today’s lecture we talked about the random numbers and the random number generators We have also discussed random numbers and pseudorandom numbers. The design constraints were also discussed.
27 trang | Chia sẻ: dntpro1256 | Ngày: 20/11/2020 | Lượt xem: 640 | Lượt tải: 0
Network Security - Lecture 18Given knowledge of the algorithm used to create the numbers and its internal state (i.e. seed), you can predict all the numbers returned by subsequent calls to the algorithm, whereas with genuinely random numbers, knowledge of one number or an arbitrarily long sequence of numbers is of no use whatsoever in predicting the next number to be generated...
20 trang | Chia sẻ: dntpro1256 | Ngày: 20/11/2020 | Lượt xem: 613 | Lượt tải: 0
Network Security - Lecture 17An example of RSA algorithm was discussed. We will talk about random numbers. The design constraints for random numbers and pseudo random numbers will be explored
35 trang | Chia sẻ: dntpro1256 | Ngày: 20/11/2020 | Lượt xem: 613 | Lượt tải: 0
Network Security - Lecture 16claimed secure against known attacks have some analyses, none practical result is very non-linear since RC4 is a stream cipher, must never reuse a key have a concern with WEP, but due to key handling rather than RC4 itself
35 trang | Chia sẻ: dntpro1256 | Ngày: 20/11/2020 | Lượt xem: 672 | Lượt tải: 0
Network Security - Lecture 15can efficiently implement on 32-bit CPU redefine steps to use 32-bit words can precompute 4 tables of 256-words then each column in each round can be computed using 4 table lookups + 4 XORs at a cost of 4Kb to store tables designers believe this very efficient implementation was a key factor in its selection as the AES cipher
35 trang | Chia sẻ: dntpro1256 | Ngày: 20/11/2020 | Lượt xem: 688 | Lượt tải: 0
Network Security - Lecture 14We discussed symmetric key cryptography We also discussed Fiestel Structure which is the basis of DES Data Encryption Standard (DES) is a type of symmetric key cryptography which uses certain steps to obtain the cipher text through plain text.
32 trang | Chia sẻ: dntpro1256 | Ngày: 20/11/2020 | Lượt xem: 587 | Lượt tải: 0
Network Security - Lecture 13We discussed transposition ciphers and a couple of examples such as Rail Fence Cipher was discussed. We have also explored the Hill Cipher and have seen how this technique can ensure security.
29 trang | Chia sẻ: dntpro1256 | Ngày: 20/11/2020 | Lượt xem: 573 | Lượt tải: 0
