Computer Security-Lecture_AES,DES 10,11.pdf
- 1. Simplified Advanced Encryption Standard Simplified Advanced Encryption Standard Dr. Ibraheem Abdulatief Lecturer, Computer Science Department Al-Obour High Institutes 10,11
- 2. Simplified Advanced Encryption Standard Simplified Advanced Encryption Standard S-AES Encryption and Decryption S-AES Key Generation S-AES Encryption S-AES Decryption
- 3. Simplified Advanced Encryption Standard Shift Row Mix Columns Add Round Key 16-bit Plain text 16-bit Cipher text Nibble Substitution Shift Row Add Round Key Nibble Substitution Add Round Key 𝒘𝟐,𝟑 16-bit Key Expand Key 𝒘𝟒,𝟓 Expand Key 𝒘𝟎,𝟏 Round 1 Round 2
- 4. Simplified Advanced Encryption Standard Assume: P= 1101 0111 0010 1000 Key0 = w0w1 = 0100 1010 1111 0101 Key1 = w2w3 = 1101 1101 0010 1000 Key2 = w4w5 = 1000 0111 1010 1111
- 5. Simplified Advanced Encryption Standard Shift Row Mix Columns Add Round Key 16-bit Plain text 16-bit Cipher text Nibble Substitution Shift Row Add Round Key Nibble Substitution Add Round Key 𝒘𝟐,𝟑 16-bit Key Expand Key 𝒘𝟒,𝟓 Expand Key 𝒘𝟎,𝟏 Round 1 Round 2
- 6. Simplified Advanced Encryption Standard Round 0 P= 1101 0111 0010 1000 Key0 = 0100 1010 1111 0101 R0= P ⊕ Key0 = 1101 0111 0010 1000 ⊕ 0100 1010 1111 0101 = 1001 1101 1101 1101
- 7. Simplified Advanced Encryption Standard Shift Row Mix Columns Add Round Key 16-bit Plain text 16-bit Cipher text Nibble Substitution Shift Row Add Round Key Nibble Substitution Add Round Key 𝒘𝟐,𝟑 16-bit Key Expand Key 𝒘𝟒,𝟓 Expand Key 𝒘𝟎,𝟏 Round 1 Round 2
- 8. Simplified Advanced Encryption Standard S-AES Encryption Round
- 9. Simplified Advanced Encryption Standard S-AES Transformation (Substitution and Shift row)
- 10. Simplified Advanced Encryption Standard Shift Row Mix Columns Add Round Key 16-bit Plain text 16-bit Cipher text Nibble Substitution Shift Row Add Round Key Nibble Substitution Add Round Key 𝒘𝟐,𝟑 16-bit Key Expand Key 𝒘𝟒,𝟓 Expand Key 𝒘𝟎,𝟏 Round 1 Round 2
- 11. Simplified Advanced Encryption Standard Round 1 1) Nibble Substitution : SubNib(1001 1101 1101 1101)= 0010 1110 1110 1110 2) Shift Row: Swap 2nd nibble and 4th nibble ShRow(0010 1110 1110 1110) = 0010 1110 1110 1110 S-Box
- 12. Simplified Advanced Encryption Standard S-AES Encryption Round
- 13. Simplified Advanced Encryption Standard Shift Row Mix Columns Add Round Key 16-bit Plain text 16-bit Cipher text Nibble Substitution Shift Row Add Round Key Nibble Substitution Add Round Key 𝒘𝟐,𝟑 16-bit Key Expand Key 𝒘𝟒,𝟓 Expand Key 𝒘𝟎,𝟏 Round 1 Round 2
- 14. Simplified Advanced Encryption Standard S-AES Transformation (Mix Column)
- 15. Simplified Advanced Encryption Standard Mix Column Table * 1 2 3 4 5 6 7 8 9 A B C D E F 2 2 4 6 8 A C E 3 1 7 5 B 9 F D 4 4 8 C 3 7 B F 6 2 E A 5 1 D 9 9 9 1 8 2 B 3 A 4 D 5 C 6 F 7 E
- 16. Simplified Advanced Encryption Standard Round 1 3) Mix Columns: MixCol (0010 1110 1110 1110) = 0010 1110 1110 1110 ∗ 1 4 4 1 = = 2 E E E ∗ 1 4 4 1 = (2∗1⊕E∗4) (E∗1⊕E∗4) (2∗4⊕E∗1) (E∗4⊕E∗1) * 1 2 3 4 5 6 7 8 9 A B C D E F 2 2 4 6 8 A C E 3 1 7 5 B 9 F D 4 4 8 C 3 7 B F 6 2 E A 5 1 D 9 9 9 1 8 2 B 3 A 4 D 5 C 6 F 7 E
- 17. Simplified Advanced Encryption Standard = (2⊕D) (E⊕D) (8⊕E) (D⊕E) = (0010⊕1101) (1110⊕1101) (1000⊕1110) (1101⊕1110) (0010⊕1101) (1110⊕1101) (1000⊕1110) (1101⊕1110) = 1111 0011 0110 0011 = 1111 0110 0011 0011
- 18. Simplified Advanced Encryption Standard Shift Row Mix Columns Add Round Key 16-bit Plain text 16-bit Cipher text Nibble Substitution Shift Row Add Round Key Nibble Substitution Add Round Key 𝒘𝟐,𝟑 16-bit Key Expand Key 𝒘𝟒,𝟓 Expand Key 𝒘𝟎,𝟏 Round 1 Round 2
- 19. Simplified Advanced Encryption Standard Round 1 4) Add round Key1 Key1 = 1101 1101 0010 1000 R1= Key1 ⊕ MixCol(ShRow(SubNib(R0))) = 1101 1101 0010 1000 ⊕ 1111 0110 0011 0011 = 0010 1011 0001 1011
- 20. Simplified Advanced Encryption Standard Shift Row Mix Columns Add Round Key 16-bit Plain text 16-bit Cipher text Nibble Substitution Shift Row Add Round Key Nibble Substitution Add Round Key 𝒘𝟐,𝟑 16-bit Key Expand Key 𝒘𝟒,𝟓 Expand Key 𝒘𝟎,𝟏 Round 1 Round 2
- 21. Simplified Advanced Encryption Standard Shift Row Mix Columns Add Round Key 16-bit Plain text 16-bit Cipher text Nibble Substitution Shift Row Add Round Key Nibble Substitution Add Round Key 𝒘𝟐,𝟑 16-bit Key Expand Key 𝒘𝟒,𝟓 Expand Key 𝒘𝟎,𝟏 Round 1 Round 2
- 22. Simplified Advanced Encryption Standard S-AES Transformation (Substitution and Shift row)
- 23. Simplified Advanced Encryption Standard Round 2 1) Nibble Substitution : SubNib(0010 1011 0001 1011)= 1010 0011 0100 0011 2) Shift Row: Swap 2nd nibble and 4th nibble ShRow(1010 0011 0100 0011) = 1010 0011 0100 0011 S-Box
- 24. Simplified Advanced Encryption Standard Shift Row Mix Columns Add Round Key 16-bit Plain text 16-bit Cipher text Nibble Substitution Shift Row Add Round Key Nibble Substitution Add Round Key 𝒘𝟐,𝟑 16-bit Key Expand Key 𝒘𝟒,𝟓 Expand Key 𝒘𝟎,𝟏 Round 1 Round 2
- 25. Simplified Advanced Encryption Standard Round 2 4) Add round Key2 Key2 = 1000 0111 1010 1111 R2= Key2 ⊕ ShRow(SubNib(R1)) = 1000 0111 1010 1111 ⊕ 1010 0011 0100 0011 = 0010 0100 1110 1100 Ciphertext = 0010 0100 1110 1100
- 26. Simplified Advanced Encryption Standard Simplified Advanced Encryption Standard S-AES Encryption and Decryption S-AES Key Generation S-AES Encryption S-AES Decryption
- 27. Simplified Advanced Encryption Standard Shift Row Mix Columns Add Round Key 16-bit Plain text 16-bit Cipher text Nibble Substitution Shift Row Add Round Key Nibble Substitution Add Round Key Inverse Shift Row Inverse Mix Columns Add Round Key 16-bit Plain text 16-bit Cipher text Inverse Nibble Substitution Inverse Shift Row Add Round Key Inverse Nibble Substitution Add Round Key 𝒘𝟐,𝟑 16-bit Key Expand Key 𝒘𝟒,𝟓 Expand Key 𝒘𝟎,𝟏 Round 1 Round 2 Round 1 Round 2
- 28. Simplified Advanced Encryption Standard Inverse Shift Row Inverse Mix Columns Add Round Key 16-bit Plain text 16-bit Cipher text Inverse Nibble Substitution Inverse Shift Row Add Round Key Inverse Nibble Substitution Add Round Key 𝒘𝟐,𝟑 16-bit Key Expand Key 𝒘𝟒,𝟓 Expand Key 𝒘𝟎,𝟏 Round 1 Round 2
- 29. Simplified Advanced Encryption Standard Assume: C= 0010 0100 1110 1100 Key0 = w0w1 = 0100 1010 1111 0101 Key1 = w2w3 = 1101 1101 0010 1000 Key2 = w4w5 = 1000 0111 1010 1111
- 30. Simplified Advanced Encryption Standard Inverse Shift Row Inverse Mix Columns Add Round Key 16-bit Plain text 16-bit Cipher text Inverse Nibble Substitution Inverse Shift Row Add Round Key Inverse Nibble Substitution Add Round Key 𝒘𝟐,𝟑 16-bit Key Expand Key 𝒘𝟒,𝟓 Expand Key 𝒘𝟎,𝟏 Round 1 Round 2
- 31. Simplified Advanced Encryption Standard Key2 = w4w5 = 1000 0111 1010 1111 C= 0010 0100 1110 1100 R0= C ⊕ Key2 = 0010 0100 1110 1100 ⊕ 1000 0111 1010 1111 =1010 0011 0100 0011
- 32. Simplified Advanced Encryption Standard Inverse Shift Row Inverse Mix Columns Add Round Key 16-bit Plain text 16-bit Cipher text Inverse Nibble Substitution Inverse Shift Row Add Round Key Inverse Nibble Substitution Add Round Key 𝒘𝟐,𝟑 16-bit Key Expand Key 𝒘𝟒,𝟓 Expand Key 𝒘𝟎,𝟏 Round 1 Round 2
- 33. Simplified Advanced Encryption Standard Inverse Shift Row Inverse Mix Columns Add Round Key 16-bit Plain text 16-bit Cipher text Inverse Nibble Substitution Inverse Shift Row Add Round Key Inverse Nibble Substitution Add Round Key 𝒘𝟐,𝟑 16-bit Key Expand Key 𝒘𝟒,𝟓 Expand Key 𝒘𝟎,𝟏 Round 1 Round 2
- 34. Simplified Advanced Encryption Standard Round 1 1) Inverse Shift Row IShRow(R0)=IShRow(1010 0011 0100 0011)= = 1010 0011 0100 0011 2) Inverse Nibble Sub ISubNib( 1010 0011 0100 0011 )= = 0010 1011 0001 1011 Inv S-Box
- 35. Simplified Advanced Encryption Standard Inverse Shift Row Inverse Mix Columns Add Round Key 16-bit Plain text 16-bit Cipher text Inverse Nibble Substitution Inverse Shift Row Add Round Key Inverse Nibble Substitution Add Round Key 𝒘𝟐,𝟑 16-bit Key Expand Key 𝒘𝟒,𝟓 Expand Key 𝒘𝟎,𝟏 Round 1 Round 2
- 36. Simplified Advanced Encryption Standard 3) Add Round 1 Key 0010 1011 0001 1011 ⊕ Key1 = 0010 1011 0001 1011 ⊕ 1101 1101 0010 1000 =1111 0110 0011 0011
- 37. Simplified Advanced Encryption Standard Inverse Shift Row Inverse Mix Columns Add Round Key 16-bit Plain text 16-bit Cipher text Inverse Nibble Substitution Inverse Shift Row Add Round Key Inverse Nibble Substitution Add Round Key 𝒘𝟐,𝟑 16-bit Key Expand Key 𝒘𝟒,𝟓 Expand Key 𝒘𝟎,𝟏 Round 1 Round 2
- 38. Simplified Advanced Encryption Standard Round 1 4) Inverse Mix Columns : MixCol (1111 0110 0011 0011) = 1111 0011 0110 0011 ∗ 9 2 2 9 = = F 3 6 3 ∗ 𝟗 𝟐 𝟐 𝟗 = (F∗9⊕6∗2) (3∗9⊕3∗2) (F∗2⊕6∗9) (3∗2⊕3∗9) = (E⊕C) (8⊕6) (D⊕3) (6⊕8) = (1110⊕1100) (1000⊕0110) (1101⊕0011) (0110⊕1000) * 1 2 3 4 5 6 7 8 9 A B C D E F 2 2 4 6 8 A C E 3 1 7 5 B 9 F D 4 4 8 C 3 7 B F 6 2 E A 5 1 D 9 9 9 1 8 2 B 3 A 4 D 5 C 6 F 7 E
- 39. Simplified Advanced Encryption Standard (1110⊕1100) (1000⊕0110) (1101⊕0011) (0110⊕1000) = 0010 1110 1110 1110 R1 = 0010 1110 1110 1110
- 40. Simplified Advanced Encryption Standard Inverse Shift Row Inverse Mix Columns Add Round Key 16-bit Plain text 16-bit Cipher text Inverse Nibble Substitution Inverse Shift Row Add Round Key Inverse Nibble Substitution Add Round Key 𝒘𝟐,𝟑 16-bit Key Expand Key 𝒘𝟒,𝟓 Expand Key 𝒘𝟎,𝟏 Round 1 Round 2
- 41. Simplified Advanced Encryption Standard Inverse Shift Row Inverse Mix Columns Add Round Key 16-bit Plain text 16-bit Cipher text Inverse Nibble Substitution Inverse Shift Row Add Round Key Inverse Nibble Substitution Add Round Key 𝒘𝟐,𝟑 16-bit Key Expand Key 𝒘𝟒,𝟓 Expand Key 𝒘𝟎,𝟏 Round 1 Round 2
- 42. Simplified Advanced Encryption Standard Round 2 1) Inverse Shift Row IShRow(R1)=IShRow(0010 1110 1110 1110)= = 0010 1110 1110 1110 2) Inverse Nibble Sub ISubNib( 0010 1110 1110 1110 )= = 1001 1101 1101 1101 Inv S-Box
- 43. Simplified Advanced Encryption Standard Inverse Shift Row Inverse Mix Columns Add Round Key 16-bit Plain text 16-bit Cipher text Inverse Nibble Substitution Inverse Shift Row Add Round Key Inverse Nibble Substitution Add Round Key 𝒘𝟐,𝟑 16-bit Key Expand Key 𝒘𝟒,𝟓 Expand Key 𝒘𝟎,𝟏 Round 1 Round 2
- 44. Simplified Advanced Encryption Standard 3) Add Round 2 Key R2= 1001 1101 1101 1101 ⊕ Key0 = 1001 1101 1101 1101 ⊕ 0100 1010 1111 0101 =1101 0111 0010 1000 Plaintext = 1101 0111 0010 1000 = D7 28
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