Data encryption standard
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The document is a detailed technical overview of the Data Encryption Standard (DES), focusing on its structure, including the Feistel function, S-boxes, and permutation processes. It provides descriptions of key operations such as key generation, initial permutation, and how data is processed through encryption rounds. Additionally, it includes various bit manipulations and illustrates the encryption mechanism in a stepwise manner.
Data encryption standard
- 1. Data Encryption Standard (DES) M.Golyani Tehran University – Kish campus Fall 2013 Copyright ©GPL Mohammad.golyani@gmail.com
- 5. DES - -
- 6. - XOR -
- 7. k f - k 0 1 1 0 0 1 0 1 1 0 0 1 1 0 1 0 K=2 F = mirror(each K bit of input) 1 0 0 1 1 0 1 0 K=2 F = mirror(each K bit of input)
- 9. m 0 0 1 1 1 1 0 0 0 1 0 0 1 1 0 f 1 - R0 L0 K0 L1 R1 DES K1 - Kn Kn-1 Rn C 0 1 Ln XOR f(Kn,Rn) 1 0 0 1 1 0 C = (Rn+1,Ln+1) Kn Li+1 = Ri Ri+1 = Li XOR f ( Ri , Ki )
- 10. c Rn 0 0 1 1 1 1 0 0 0 1 0 0 1 1 0 Ln XOR f(Kn,Rn) 1 - Kn Ln-1 - Rn-1 Kn-1 - f K0 Ri = Li+1 L0 m 0 1 R0 1 0 0 1 m = (L0 , R0) 1 0 Li = Ri+1 XOR f ( Li+1, Ki )
- 11. DES Feistel function f Backdoor DES - P-Box S-Box DES -
- 15. P-Box S-Box P-Box S-Box - y = 3x2 + 4x -1 S-Box S-Box - - -
- 22. DES
- 26. m 0 1 1 0 0 32 bit 1 0 DES 1 - 32 bit R0 L0 K0 L1 f R1 DES - K1 f K16 Ri XOR - Li Ri+1 R14 L14 XOR f(K14,R14) (L15) C 0 1 (R15) 1 0 0 1 1 0 Ri Li+1 -
- 27. DES XOR L0 f K0 R0 - L0 K0 R0 f L1 R1 Li+1 = Ri L1 = R0 Ri+1 = Li XOR f ( Ri , Ki ) R1 = L0 XOR f ( R0 , K0 )
- 28. DES K0 XOR K K0 K0 - - K0 = 101100 001001 001011 001010 011100 001000 000101 000101 K8 = 001110 010001 101010 001010 010100 011100 001000 111000 K1 = 101100 000001 101011 010010 011101 101000 000001 001100 K9 = 001100 000011 100011 001100 000100 010001 110000 001100 K “4950515253545556”= 000100 000110 110001 010100 100010 000011 000010 110100 - K2 = 001101 000111 101001 010000 000000 001011 010111 001010 10 K3 = 000001 100111 010101 010100 001011 001011 010000 100001 K11= 010001 000110 110100 110100 001000 010110 101010 100101 K4 = 010011 100100 010101 010101 011010 100100 110001 100010 K12= 110001 101010 010100 100101 001100 100000 100010 010011 K5 = 010011 111100 000100 101001 000011 001100 100100 011010 K13= 110010 111000 011000 100011 100001 110000 000100 010111 K6 = 100010 111000 000110 101011 100001 010101 010001 010000 K14= 111010 011001 001010 101010 000001 110010 001111 000000 K7 = 101110 010000 101010 001011 110010 011000 001001 100000 K15= 101000 011001 001010 101010 010101 000010 001001 000011
- 31. DES
- 33. DES
- 34. DES m 0 1 1 0 32 bit 0 1 0 1 32 bit R0 L0 K0 L1 R1 K1 K16 R14 L14 XOR f(K14,R14) (L15) C 0 1 (R15) 1 0 0 1 1 0
- 35. DES XOR K0 E(R0) 0 0 0 0 1 0 1 1 1 1 1 1 1 1 1 0 0 0 1 0 1 1 1 48-bit 48-bit 48-bit E(R0) K0 E(R0) xor K0 S-Box f
- 36. DES S-Box P-Box f 0 0 0 0 S1 1 0 1 1 S2 S3 S4 S5 Straigh P-Box 1 S6 1 1 1 1 0 0 0 1 S7 1 0 1 S8 1 1
- 37. DES S-Box 14 4 13 1 S1 0 15 7 4 2 15 11 8 3 10 6 12 5 9 0 7 15 1 4 14 2 13 1 10 6 12 11 9 5 3 8 3 13 4 3 10 5 0 1 14 8 13 6 15 12 8 2 4 9 2 11 15 12 9 1 3 15 4 1 13 12 7 11 4 2 8 7 13 14 3 0 8 5 14 12 11 15 1 13 8 11 5 6 15 0 2 12 5 10 14 7 9 3 4 13 6 4 9 8 15 3 0 11 1 1 10 13 0 6 7 2 12 4 S5 0 7 10 11 6 1 14 11 2 12 4 4 2 6 10 2 7 13 1 1 11 10 13 7 11 8 12 7 4 15 14 3 11 5 8 5 5 0 15 10 3 8 15 9 12 5 S7 1 9 5 3 0 14 9 10 4 6 S6 2 9 14 15 5 5 0 15 14 2 9 2 3 12 S8 7 11 4 2 5 14 9 2 8 5 11 12 4 15 7 2 12 1 10 14 9 1 1 14 7 4 2 1 13 14 0 11 3 8 12 3 7 0 4 12 5 9 12 14 2 0 5 11 8 4 10 1 13 11 6 5 15 10 11 14 1 7 4 2 14 6 6 15 11 1 10 9 4 14 7 8 5 1 15 13 8 10 3 4 9 2 15 7 12 9 6 0 3 0 13 3 5 12 2 15 8 8 4 7 12 0 9 11 5 8 2 12 9 8 3 9 5 10 6 2 2 13 2 7 3 8 12 6 2 11 6 9 10 1 1 10 6 5 11 12 7 12 1 10 15 9 10 15 4 5 2 13 12 0 6 10 1 13 8 1 7 14 10 15 6 4 10 7 8 7 3 14 5 5 10 6 1 10 14 3 6 11 13 8 3 15 0 9 0 12 11 7 13 15 1 4 13 0 11 7 4 11 13 12 3 6 9 9 3 8 13 3 12 9 1 2 12 10 6 6 5 4 11 2 14 15 0 9 S4 3 15 13 0 14 9 1 14 2 13 6 15 0 4 0 14 7 11 10 4 13 1 13 8 10 1 13 7 4 8 14 12 0 6 13 3 15 5 8 7 15 2 5 11 3 14 10 0 9 14 6 9 S2 8 14 6 11 3 7 10 0 S3 7 - 7 6 3 14 5 0 8 13 0 12 7 6 11 0 14 9 6 10 13 15 3 4 10 8 13 15 12 9 0 3 5 5 2 8 6 11
- 38. DES S-Box 0 - 0 0 S1 0 S1 1 2 3 0 14 4 13 1 1 0 15 7 2 4 4 5 7 2 15 11 8 8 9 10 11 12 13 14 15 3 10 6 12 5 9 0 7 4 14 2 13 1 10 6 12 11 9 5 3 8 3 10 5 0 1 14 8 13 6 3 15 12 8 6 2 4 9 2 11 15 12 9 1 7 7 5 11 3 14 10 0 6 13 S-Box P-Box S-Box 1 0 1 1 1 0 0 1 1 0 1 0 0 1 1 0 1 1 1 1 0 1 0 0 1 1 1 1 1 0 1 1
- 39. DES m 0 1 1 0 32 bit 0 1 0 1 32 bit R0 L0 K0 L1 R1 K1 K16 R14 L14 XOR f(K14,R14) (L15) C 0 1 (R15) 1 0 0 1 1 0
- 41. DES
- 42. DES L0 K0 R0 f L1 R1 Li+1 = Ri L1 = R0 Ri+1 = Li XOR f ( Ri , Ki ) R1 = L0 XOR f ( R0 , K0 )
- 44. DES m 0 1 1 0 32 bit 0 1 0 1 32 bit DES R0 L0 K0 L1 K16 R14 L14 XOR f(K14,R14) (L15) 0 1 P-Box R1 K1 C - (R15) 1 0 0 1 1 0 IP P-Box -
- 46. DES
- 47. DES DES “_MAGMAG_” “4950515253545556” 01000101 00100011 10100011 00010101 10010000 01001001 11101100 00111101 “4523a3159049ec3d” _MAGMAG_ 5f4d41474d41475f 4950515253545556 IPQRSTUV 4523a3159049ec3d
- 51. DES DES DES -
- 53. Secure MCU with 32-bit ARM SC300 CPU, SWP interface, NESCRYPT cryptoprocessor and high-density Flash memory
- 54. DES - XOR Electronic Code Book ECB DES CBC, CFB, OFB, CTR DES DES DES - -
- 55. - Introduction to modern cryptography, Jonathan Katz, Yehuda Lindell - The Day DES Died, SANS Institute InfoSec Reading Room - Practically secure Feistel ciphers, Lars R. Knudsen, Arhus University, Denmark - Implementation of Data Encryption Standard Using Reversible Gate Logic, Nuthan.A.C - DES, CSIS 5857: Encoding and Encryption - DES Walk Through, Kathryn Neugent, April 16, 2011 - United States Patent, 3,798,359 Mar.19,1974 - Cryptography and Network Security, Behruz Forouzan - ,…