Differential Cryptanalysis

Differential cryptAnalysis F - plain text pairs . And he finds out the difference Splits CT into many messages He chooses corresponding between the Pairs anduCT Then he tries out different PT and finds out the correct one Rinear cryptAnalysis = Mathematical formula's or unear approximation is used. - PT. is chosen and its binary is taken out and CT is finded Out - XOR is used - Strict Avelenche criterion (SAC) it states that any output bit j of an S-box should change with probability 1/2 when any single input bit to i is univerted for all i,j folly Bit independence criterion (BIC) stugent It states that output bits j and k should change independently when any single input bit i is inverted for all j and K

Q8. Encrypt the text "love". using with a Key [is 7] C4 marks) Hill april 5 Q.6 Ans: C = (P+20) mod 26 Q1. Ans Substitution boxes should be P explained here Q8.Ans 4. down Lord 9 agrees that 3969 LOVE 37123" list 14 21 4 prosed

9 5 7 11 mod 26. D 155 mod 26. 153 5 = 25 26 23 mod 26. 7 4 205 = 133 mod 26. (04/18) 13 F 5 = 23 26 153 3 130 23 CT ZXXD 18 sby 199+ 16 6. C = (P+20) mod 26 205 PT = This is an exercise 20 21 105 C= (19+20) mod 26 10 = 39 mod 26 28 Don't 133 = 13 N 26/ 205 C = (7+ 20) mod26 29 27 mod on 26 39 I B 1 = 66 26 139 C = C ++20) mod 26 26 13 = 28 mod 26 2 C

C - (18 +201) mod 26. V 38 mod 26 = 12 M 20 18 C = e C = KY 261 C = (20) mod 26 20 U = C = (13-120) mod. 26 13 20 = 7 H 33 C = (4+- 20) mod 26 26 33 26 = 24 mod 26 = 24 y 23 28 20 C = (23-20) mod 26 43 = 17 R I y 26 34,303 C = 24 26 17 C = (17+20) mod 26 26 87 = 11 L 26 11 C= = (2+20, mod26 = 22 W C = be C C=M

C=Y. NBCMCMUHYRYLWCMY CT Q.7. b) K POR computer OT copptography COMPU TERAB D F G H 1/J K L N S & W x x