This question relates to hash functions for block ciphers Block size = 4 bits Hash size = 4 bits Encryption function: Divide the key into two halves: LK and RK; Divide the plaintext into two halves: LT and RT; Then ciphertext= LC||RC where LC=LK XOR RT; and RC = RK XOR LT; where LC, RC, LT, and RT are each 2 bits; Plaintext and ciphertext are each 4 bits. g(H) = a 4-bit string that is equal to the complement of bits in H; For example, if H=A (Hexa) = 1010 (binary); then g(H)= 0101 H0 = Initial hash = C (in Hexa) Given message M:  D9 (in Hexa); a. Determine the hash (in hexadecimal) of the message M using Martyas-Meyer-Oseas hash function b. Determine the hash (in hexadecimal) of the message M using Davis-Meyer hash function c. Determine the hash (in hexadecimal) of the message M using Migayuchi-Preneel hash function

Assume a hash table utilizes an array of 13 elements and that collisions are handled by separate chaining. Considering the hash function is defined as: h(k)=k mod 13. i) Draw the contents of the table after inserting elements with the following keys: 36, 243, 261, 180, 217, 180, 21, 16, 182, 202, 91, 97, 166, 78, 33, 70, 51, 58.

When a message is sent, how is the hash value stored securely? Does it function if the secret key is not retrieved?

1. An open hashing scheme requires the use of random access ( true /false ). 2. A good hashing function should ___ distribute the records amongthe buckets. 3. For an open hashing scheme with 100 buckets and 4000 records,the average number of record reads to locate a record is equal to___.

Please do both questions. Thank you in advance. Subject- Security Governance Type 1: Calculation of hash values for given keys –In this type of questions, hash values are computed by applying given hash function on given keys. Que – 1. Given the following input (4322, 1334, 1471, 9679, 1989, 6171, 6173, 4199) and the hash function x mod 10, which of the following statements are true? i. 9679, 1989, 4199 hash to the same valueii. 1471, 6171 has to the same valueiii. All elements hash to the same valueiv. Each element hashes to a different value(A) i only(B) ii only(C) i and ii only(D) iii or iv Type 2: Insertion of keys into hash table using linear probing as collision resolution technique –In linear probing technique, collision is resolved by searching linearly in the hash table until an empty location is found. Que – 2. The keys 12, 18, 13, 2, 3, 23, 5 and 15 are inserted into an initially empty hash table of length 10 using open addressing with hash function h(k) = k mod 10 and…

Exercise 2 (MAC schemes derived from block ciphers( Let E denote the family of encryption functions for a block cipher where plaintext blocks, ciphertext blocks, and keys are each n = 80 bits in length. Let H {0, 1} {0, 1}" be a hash function. Assume that plaintext messages m all have bit-lengths that are multiples of n; we write m = (my, m₂,...,m), i.e. m is composed of t blocks m, of n bits each. Consider the following MAC schemes, each using an n-bit secret key k. 1. MAC (m) = ₁, where co = 0, and c, =c-1m, Ex(m) for 1 ≤ i ≤t. 2. MAC (m) Ek(H(m)). Are any of these MAC schemes secure? Justify your answer and clearly state any assumptions you make.

Digital forensics: Suppose that we a record but not sure which one is the original one and which one has been modified: A) Bob leaves the hotel at 7:00 pm B) Bob leaves the hotel at 6:00 pm Fortunately, we have the hash value of the original record, calculated by SHA-256: 2655a8151189efae706db96460d368ab6adb9f5a1b88e5aa5c6ea18ba65beadd Please tell us which one is the original one, A or B?  (Hint: You can use the SHA-256 calculator at https://xorbin.com/tools/sha256-hash-calculator).

8-1 Discussion: Cryptography V Available on Jun 18, 2022 11:59 PM. Submission restricted before availability starts. As you learned this week, RSA is the most widely used public key cryptosystem. In this discussion, you will apply RSA to post and read messages. For this reflection discussion, use the prime numbers p = 3 and q = 11. Using the public key e = 3, post a phrase about something that you found interesting or relevant in this course. Include only letters and spaces in your phrase. Represent the letters A through Z by using the numbers 01 through 26, and represent a space by the number 32. Treat upper case and lower case letters as the same. Optional: If you want to include punctuation characters, you can use the numbers 27 through 31 for that, but you must inform your classmates that you did. How did you calculate your value for d? As a check, the phrase "A CAB" would be represented by "01 32 03 01 02" and would be encrypted as "01 32 27 01 08".

10. Hash Table size = 13 Hash Function = H (x) = x mod 13 Collision Resolution = Quadratic probing = h+i? :2 Кeys %3D 10, 100, 32, 45, 58, 126, 3, 29, 200, 400, 0, 21, 15. Pickup the correct statement: P: The Key '58' is stored at location: 10 Q: The Key 126’ is stored at location: 9 R: The Key '0' is stored at location: 0 S: The Key '10' is stored at location: 11 T: The Key '15' is stored at location: 12 U: The Key '400' is stored at location: 10 V: The Key '29' is stored åt location: 3

**GIVEN MESSAGE IS CAB2; IT IS NOT AB12**This homework relates to hash functions for block ciphers (sec 11.3.2) Block size = 8 bits Hash size = 8 bits Encryption function: Divide the key into two halves: LK and RK; Divide the plaintext into twohalves: LT and RT; Then ciphertext= LC||RC where LC=LK XOR RT; and RC = RK XOR LT;where LC, RC, LT, and RT are each 4 bits; Plaintext and ciphertext are each 8 bits. g(H) = an 8-bit string that is equal to the complement of bits in H; For example, if H=A3 (Hexa)= 10100011 (binary); then g(H)= 01011100 H0 = Initial hash = 11001010Given a message m: CAB2 (in Hexa);Q1. Determine the hash (in hexadecimal) of the message M using Martyas-Meyer-Oseas hashfunction (Fig. 11.7).Q2. Determine the hash (in hexadecimal) of the message M using Davis-Meyer hash function(Fig. 11.6)Q3. Determine the hash (in hexadecimal) of the message M using Migayuchi-Preneel hashfunction (Fig. 11.6) **GIVEN MESSAGE IS CAB2; IT IS NOT AB12**