(9) (Knapsack cryptosystem) Let r = (1, 3, 7, 15, 30, 61, 124). Let A = 5 and B = 253. (a) Compute the sequence where M = (M₁, M2, M3, M4, M5, M6, M7) M₁ Arį (mod B) (b) Choose the binary plaintext for i=1,2,...,7. x = (1, 0, 1, 1, 0, 1, 1) and compute the ciphertext S = x. M. (c) Compute S'A¹S (mod B) (d) Solve the subset-sum problem S' using the superincreasing sequence r.
(9) (Knapsack cryptosystem) Let r = (1, 3, 7, 15, 30, 61, 124). Let A = 5 and B = 253. (a) Compute the sequence where M = (M₁, M2, M3, M4, M5, M6, M7) M₁ Arį (mod B) (b) Choose the binary plaintext for i=1,2,...,7. x = (1, 0, 1, 1, 0, 1, 1) and compute the ciphertext S = x. M. (c) Compute S'A¹S (mod B) (d) Solve the subset-sum problem S' using the superincreasing sequence r.
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
Related questions
Question
![**Knapsack Cryptosystem Example**
---
### Problem Description
Given:
- Superincreasing sequence: \( \mathbf{r} = (1, 3, 7, 15, 30, 61, 124) \).
- Constants: \( A = 5 \) and \( B = 253 \).
#### (a) Compute the Sequence
Let \( M = (M_1, M_2, M_3, M_4, M_5, M_6, M_7) \), where:
\[ M_i \equiv A r_i \ (\text{mod} \ B) \ \text{for} \ i = 1, 2, \ldots, 7. \]
#### (b) Choose the Binary Plaintext
Let the plaintext be \( x = (1, 0, 1, 1, 0, 1, 1) \).
Compute the ciphertext:
\[ S = x \cdot M. \]
#### (c) Compute Intermediate Value
Compute the intermediate value:
\[ S' = A^{-1} S \ (\text{mod} \ B). \]
#### (d) Solve the Subset-Sum Problem
Solve the subset-sum problem \( S' \) using the superincreasing sequence \( \mathbf{r} \).
---
### Explanation of Parameters and Steps
1. **Superincreasing Sequence \( \mathbf{r} \)**: This sequence is a specific type of sequence where each element is greater than the sum of all previous elements. In this case, \( \mathbf{r} = (1, 3, 7, 15, 30, 61, 124) \).
2. **Computing \( M \)**:
\[ M_i \equiv A r_i \ (\text{mod} \ B) \]
- Multiply each element of \( \mathbf{r} \) by \( A \) and then take modulo \( B \) to find each \( M_i \).
3. **Binary Plaintext \( x \)**: A binary vector representing the plaintext message. Each element of the vector is a bit (0 or 1).
4. **Ciphertext Calculation**:
\[ S = x \cdot M \]
- Compute the dot product of the plaintext vector \( x \) with the computed sequence \( M](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2Ffa332eac-d846-4704-9340-0a50b86bfcea%2F241a7bee-b7a9-4c82-a8f0-4b11c224973b%2Flw9yw6i_processed.png&w=3840&q=75)
Transcribed Image Text:**Knapsack Cryptosystem Example**
---
### Problem Description
Given:
- Superincreasing sequence: \( \mathbf{r} = (1, 3, 7, 15, 30, 61, 124) \).
- Constants: \( A = 5 \) and \( B = 253 \).
#### (a) Compute the Sequence
Let \( M = (M_1, M_2, M_3, M_4, M_5, M_6, M_7) \), where:
\[ M_i \equiv A r_i \ (\text{mod} \ B) \ \text{for} \ i = 1, 2, \ldots, 7. \]
#### (b) Choose the Binary Plaintext
Let the plaintext be \( x = (1, 0, 1, 1, 0, 1, 1) \).
Compute the ciphertext:
\[ S = x \cdot M. \]
#### (c) Compute Intermediate Value
Compute the intermediate value:
\[ S' = A^{-1} S \ (\text{mod} \ B). \]
#### (d) Solve the Subset-Sum Problem
Solve the subset-sum problem \( S' \) using the superincreasing sequence \( \mathbf{r} \).
---
### Explanation of Parameters and Steps
1. **Superincreasing Sequence \( \mathbf{r} \)**: This sequence is a specific type of sequence where each element is greater than the sum of all previous elements. In this case, \( \mathbf{r} = (1, 3, 7, 15, 30, 61, 124) \).
2. **Computing \( M \)**:
\[ M_i \equiv A r_i \ (\text{mod} \ B) \]
- Multiply each element of \( \mathbf{r} \) by \( A \) and then take modulo \( B \) to find each \( M_i \).
3. **Binary Plaintext \( x \)**: A binary vector representing the plaintext message. Each element of the vector is a bit (0 or 1).
4. **Ciphertext Calculation**:
\[ S = x \cdot M \]
- Compute the dot product of the plaintext vector \( x \) with the computed sequence \( M
Expert Solution

This question has been solved!
Explore an expertly crafted, step-by-step solution for a thorough understanding of key concepts.
Step by step
Solved in 3 steps

Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, computer-science and related others by exploring similar questions and additional content below.Recommended textbooks for you

Database System Concepts
Computer Science
ISBN:
9780078022159
Author:
Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan
Publisher:
McGraw-Hill Education

Starting Out with Python (4th Edition)
Computer Science
ISBN:
9780134444321
Author:
Tony Gaddis
Publisher:
PEARSON

Digital Fundamentals (11th Edition)
Computer Science
ISBN:
9780132737968
Author:
Thomas L. Floyd
Publisher:
PEARSON

Database System Concepts
Computer Science
ISBN:
9780078022159
Author:
Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan
Publisher:
McGraw-Hill Education

Starting Out with Python (4th Edition)
Computer Science
ISBN:
9780134444321
Author:
Tony Gaddis
Publisher:
PEARSON

Digital Fundamentals (11th Edition)
Computer Science
ISBN:
9780132737968
Author:
Thomas L. Floyd
Publisher:
PEARSON

C How to Program (8th Edition)
Computer Science
ISBN:
9780133976892
Author:
Paul J. Deitel, Harvey Deitel
Publisher:
PEARSON

Database Systems: Design, Implementation, & Manag…
Computer Science
ISBN:
9781337627900
Author:
Carlos Coronel, Steven Morris
Publisher:
Cengage Learning

Programmable Logic Controllers
Computer Science
ISBN:
9780073373843
Author:
Frank D. Petruzella
Publisher:
McGraw-Hill Education