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Cryptography

Cryptography. Symmetric Cryptosystems. Block Ciphers: Classical examples. Affine Cipher Affine Linear and Linear Cipher Vigenère Hill We needed some linear algebra!. Affine Cipher. Example: Cryptanalysis of the Affine Cipher. Intermezzo: Matrices over Rings.

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Cryptography

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  1. Cryptography

  2. Symmetric Cryptosystems

  3. Block Ciphers:Classical examples • Affine Cipher • Affine Linear and Linear Cipher • Vigenère • Hill • We needed some linear algebra!

  4. Affine Cipher

  5. Example: Cryptanalysis of the Affine Cipher

  6. Intermezzo:Matrices over Rings

  7. Intermezzo:Invertible Matrices

  8. Intermezzo:Invertible Matrices

  9. Intermezzo:Invertible Matrices

  10. Intermezzo:Invertible Matrices

  11. Intermezzo:Affine Linear Functions

  12. Intermezzo:Affine Linear Functions

  13. Affine Linear Cipher

  14. Affine Linear Cipher

  15. Example:Affine Linear Cipher - Vigenère

  16. Example:Linear Cipher - Hill

  17. Example:Linear Cipher – Permutation Cipher

  18. Cryptanalysis of the Affine Linear Cipher

  19. Cryptanalysis of the Affine Linear Cipher

  20. Cryptanalysis of the Affine Linear Cipher

  21. Example: Cryptanalysis of the Affine Linear Cipher FUSS.

  22. Block Ciphers:Remark Secure block ciphers must not be (affine) linear or easy to approximate by linear functions!!!

  23. Block Ciphers:Remark Implementation of a (non-linear!) substitution in a block cipher often occurs through a look-up table, called S-box.

  24. Block Ciphers:Advanced examples • DES – Feistel Cipher • AES – Rijndael

  25. DES

  26. DES:Feistel Cipher An iterated block cipher is a block cipher involving the sequential repetition of an internal function called rounds. (iterated)

  27. DES:Feistel Cipher

  28. DES:Feistel Cipher

  29. DES:Algorithm

  30. DES:Algorithm

  31. DES:Algorithm

  32. DES:Algorithm

  33. DES:Algorithm

  34. DES:Algorithm

  35. DES:Algorithm

  36. DES:Algorithm

  37. DES:Algorithm

  38. DES:S-Boxes

  39. DES:Algorithm

  40. DES:Algorithm

  41. DES:Algorithm

  42. DES:Algorithm

  43. DES:Algorithm

  44. DES:Algorithm

  45. DES:Algorithm

  46. Example:DES Key

  47. Example:S-Box

  48. Example:DES

  49. Example:DES

  50. Example:DES

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