solve 1-6
cryptography
1. (1 point) Consider the hex strings A=0x5e7ddec4529cc6fc and B=0xa28a7242612bdfe4. its (eg. 010101010101). These come in order s0s1s2s11. a) What is AB in hexadecimal? Please give your answer a leading 0x and use lowercase letters only. hexadecimal: Atsweris) subuittra: - 110110101111 b) Suppose that A was generated uniformly at random from (incorrect) 4. (1 point) Note: The notation from this problem is from Understanding Cryptography by Paar and Pelal. all 8 byte strings. What is the probability that the second binary digit of A is 1 ? Suppose you have an LFSR with 6 state bits. The first 12 bits of output produced by this LFSR are c) Suppose that A was generated uniformly at random from all 8 byte strings. What is the probability that the second binary digit of AB is 1 ? 011110110011=s0s1s2s3s4s5s657s8s9s10s11 The first bit produced is the leftmes cently produced is the rightmost bit. Answer(s) subunitted: a) What is the initial state of the LFSR? Please enter your - 0xec84d4404b2017e4 answer as unspaced binary digits (e.g. 010101 to represent - 0.5 s5=0,s4=1,s3=0,s2=1,s1=0,s0=1). - 0.5 b) What are the tap bits of the LFSR? Please enter your (score 0.666666686534882 ) answer as unspaced binary digits (e.g. 010101 to represent 2. (I point) p5=0,p4=1,p3=0,p2=1,p1=0,p0=1 ). A cryptography student has accidentally used the same keystream to encrypt two different messages, M1 and M2. We know that the ciphertexts are C1=0x3c2fec7c7ed56e50 and C2=0 ara2e8974a19615869. We also happen to know that M1=060a292/5b70ce906. Answerts) sulumithet: - 011001 (incorrect) 5. (1 point) Note: The notation from this problem is from leading 0x and use lowercase letters only. Understanding Croplography by Paar and Peltl. Consider the LFSR represented by the polynomial x4+x2+ b) What is the keystream? Please give your answer a leading x+1. 0x and use lowercase letters only. What are the tap bits of the LFSR? Please enter your answer as unspaced binary digits (e.g. 010101 to represent p5=0,p4= 1,p3=0,p2=1,p1=0,p0=1). Hint: These are all 8 byte numbers and will fit in an unsigned long type on most systems. Answer(s) submitted: - Oxf06633ci742ae70d - Ox5e8c6489ed478744 Answer(s) subminnt: - 1101 (incorrect) 6. (1 point) Note: The notation from this problem is from (incorrect) Understanding Cryptography by Paar and Peltl. 3. ( 1 point) Consider the LFSR represented by the polynomial x4+x3+ Suppose you have an LFSR with state bits (also known x+1. as the seed) (s5,s4,s3,s2,s1,s0)=(0,0,1,1,1,1) and tap bits What are the tap bits of the LFSR? Please enter your answer (also known as feedback coefficients) ( p5,p4,p3,p2+p1+p0)= as unspaced binary digits (e.g. 010101 to represent p5=0,p4= (0,1,1,0,0,1). What are the first 12 bits output by this LFSR
