9.10. Let F be a secure block cipher with blocklength 2. Below is an encryption scheme for plaintexts M = {0, 1}². Formally describe its decryption algorithm and show that it does not have CCA security. Enc(k, m): re {0,1}^ c1 := F(k,r) C2 := r O F(k, m) return (c1, c2) KeyGen: k+ {0, 1}^ return k

9.10. Let F be a secure block cipher with blocklength 2. Below is an encryption scheme for plaintexts M = {0, 1}². Formally describe its decryption algorithm and show that it does not have CCA security. Enc(k, m): re {0,1}^ c1 := F(k,r) C2 := r O F(k, m) return (c1, c2) KeyGen: k+ {0, 1}^ return k

Database System Concepts

7th Edition

ISBN:9780078022159

Author:Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan

Publisher:Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan

Chapter1: Introduction

Section: Chapter Questions

Problem 1PE

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DNA is sequence of bases A, G, T, C. Let DNA [ab] be the subsequence of DNA starting from index a finishing in b inclusive, and DNA[a..] be the subsequence of DNA starting from index a to the end. We could perform the following ops on DNAS: cross operation - they take DNA1 and DNA2 and numbers kl and k2. Then two new DNAS are created: DNA3 = DNA1[1.,k1]+DNA2[k2+1..] and DNA4 = DNA2[1..k2]+DNA1[k1+1..].mutate operation – they take a DNA, number k and one of the bases. Then they replace the base in position k in DNA with that base. also, they need to know certain characteristics of those DNAS. So, they can perform count operation - they take DNA and numbers k1 and k2 (k1 <= k2). This operation should return the number of A, G, T, C bases in DNA[k1,k2].The initial DNAS are numbered from 1 ton, where n is the amount of those DNAS. The new DNAS the first line of input file contains number n- the number of initial DNAS. Each of the following n lines contains the description of each DNA. The…
3. We shall work with an RSA encryption exponent e that is a prime. For this application, the bigger e is, the more compression we get. Let Ie as in Section 10.3 using an appropriate length parameter l. We also choose a random y e Z. The values e, n, and y are chosen once and for all, and together they determine a hash function Hrsa defined over (Z; × Ie, Z*) as follows: for a E Z, and b e le, we define {0, ..., e – 1}. Let n be an RSA modulus, generated Hrsa (a, b) := a°y". Show that Hrsa is collision resistant under the RSA assumption.
RSA is an exponentiation cipher that is used in public key cryptography. Two entities, A and B would wish to exchange data using RSA algorithm and have chosen two prime numbers p and q such that p = 7 and q = 11. Assume a cryptosystem in which each letter of the alphabet is represented by a number between 00 (A) and 25(Z) and a space is represented by 26. A and B have also agreed to generate cryptographic keys such that the private and public key pair for A is d and e respectively while the private and public key pair for B is f and g respectively. Take the key values as follows: d= 53, e = 17, f = 13 and g = 37. A wants to send the message "MY SON " to B in such a way that BOTH the message's confidentiality and authenticity of the sender are preserved. Explain the requirements on both the sender side and the receiver side that will ensure both the message confidentiality and sender authentication for this communication. Clearly show the computations performed by the sender to…
13. Consider the following code segment. def magic(li, key): low = 0 high = len(li) while low key: low = mid + 1 if li[mid] < key: high = mid - 1 return -1 Which algorithm is depicted above? (a) Linear search (b) Binary search (c) Selection sort (d) Insertion sort
Exercise 11.3-4, page 269, in the textbook. Consider a hash table of size m = 1000 and a corresponding hash function h(k) = [m(kA mod 1)] for A = (√5 - 1)/2. Compute the locations to which the keys 61, 62, 63, 64 and 65 are mapped. vt
use java programming lanuage if needed to explain
4. Using the Finite Galois Field, solve the operation of 01.89 Đ02.F1003.18 Đ01.4E (the given strings are in Hexadecimal). Give steps by steps details of your calculation. 5. Using the simplified RC4 Algorithm of 8 bytes (rather than the full 256 bytes), find the final Keystream and Cipherpext of the following Input string: S-Array of length 8, [SO S1 S2 S3 S4 S5 S6 S7] = [0 1 2 3 4 5 6 7] Key, K = [3 14 1 5] Plaintext, PT = [6 1 5 4] Hint: For the simplified stream generation, you can use this pseudocode (only up to the PT length): /* Initialization */ set i and j = o for i = i+ 1 to length of PT j = j + S[i] mod 8 [IS []s doms t = S[i] + S[j] mod 8 Keystream = end for
in 20 min
). This problem is about the chaining method we discussed in the class. Problem 3 (, Consider a hash table of size N = 11. Suppose that you insert the following sequence of keys to an initially empty hash table. Show, step by step, the content of the hash table. Sequence of keys to be inserted:
7.8. Suppose F is a secure PRP with blocklength n + λ. Below is the encryption algorithm for a scheme that supports plaintext space M = {0, 1}": Enc(k, m): r← {0,1}^ return F(k, m||r) (a) Describe the corresponding decryption algorithm. (b) Prove that the scheme satisfies CPA$ security.
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please help me to solve this simple operation of paython 3- spam = 'This is a computer.'spam[2:7]: spam[7:]: len(spam):