COMP6300 Applied Cryptography-Elgamal cryptosystem taught in the lecture

$20 Bonus + 25% OFF

Securing Higher Grades Costing Your Pocket?
Book Your Assignment at The Lowest Price
Now!

Students Who Viewed This Also Studied

COMP6300 Applied Cryptography

Task:

Question 1 (8 marks)

This question tests your knowledge of what constitutes a group. Let n be a composite number. Let X = {1, 2, . . . , n − 1}.
(a) Let x ∈ X. Show that if there are integers a, b such that ax + bn = 1, then gcd(x, n) = 1. (2 marks)
(b) Let x ∈ X. Show that if gcd(x, n) 6= 1 then ax ≡ 1 (mod n) has no solution for any integer a. (2 marks)
(c) Show that there is at least one element x ∈ X, such that gcd(x, n) 6= 1. (2 marks)
(d) Let ∗ be multiplication modulo n. That is, for x, y ∈ X, x ∗ y = xy (mod n). Prove that (X, ∗) is not a group. (2 marks)

Question 2 (4 marks)

An encryption system is considered malleable if given a ciphertext of some unknown plaintext, it is possible to obtain a valid ciphertext of a related plaintext without even knowing the contents of the plaintext. This is problematic depending on the application. For instance, in bidding for a contract, a company might outbid its competitor by simply multiplying it’s rival company’s encrypted bid by 0.9, without even knowing the
bid [DDN03]. The following questions relates to the malleability of the Elgamal cryptosystem taught in the lecture.

(a) Suppose we are given the ciphertext c = (c1, c2) of some unknown message m, where c1 ≡ gk (mod p)for some unknown random integer k ∈ Zp−1 and c2 ≡ m · hk(mod p), where h is the public key of some unknown private key x, in the Elgamal cryptosystem. Let m0 be a message that you know. Can you obtain a valid ciphertext of the message m · m0 without knowing m? (2 marks)

(b) Let p = 739. Given the following ciphertext of some message m1 encrypted using randomized Elgamal, what is the ciphertext of m1 · m2, where m2 ≡ 2 (mod p)? Show the steps in PARI/GP. (1 mark) (c1, c2) = (246, 609)Note that the integers are reduced modulo p.

(c) Continuing from part(c), suppose the private key is x = 419. What is the message m1? (1 mark)

Question 3

(a) Show that if X is not uniformly distributed then necessarily one of the pi s is > 1/n. (2 marks)

(b) Show that if X is not uniformly distributed then F∞(X)

(c) Argue that min-entropy is the highest if X is uniformly distributed. What is the min-entropy (E∞(X)) in this case

COMP6300 Applied Cryptography

Answer in Detail


Solved by qualified expert

Get Access to This Answer

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Hac habitasse platea dictumst vestibulum rhoncus est pellentesque. Amet dictum sit amet justo donec enim diam vulputate ut. Neque convallis a cras semper auctor neque vitae. Elit at imperdiet dui accumsan. Nisl condimentum id venenatis a condimentum vitae sapien pellentesque. Imperdiet massa tincidunt nunc pulvinar sapien et ligula. Malesuada fames ac turpis egestas maecenas pharetra convallis posuere. Et ultrices neque ornare aenean euismod. Suscipit tellus mauris a diam maecenas sed enim. Potenti nullam ac tortor vitae purus faucibus ornare. Morbi tristique senectus et netus et malesuada. Morbi tristique senectus et netus et malesuada. Tellus pellentesque eu tincidunt tortor aliquam. Sit amet purus gravida quis blandit. Nec feugiat in fermentum posuere urna. Vel orci porta non pulvinar neque laoreet suspendisse interdum. Ultricies tristique nulla aliquet enim tortor at auctor urna. Orci sagittis eu volutpat odio facilisis mauris sit amet.

Tellus molestie nunc non blandit massa enim nec dui. Tellus molestie nunc non blandit massa enim nec dui. Ac tortor vitae purus faucibus ornare suspendisse sed nisi. Pharetra et ultrices neque ornare aenean euismod. Pretium viverra suspendisse potenti nullam ac tortor vitae. Morbi quis commodo odio aenean sed. At consectetur lorem donec massa sapien faucibus et. Nisi quis eleifend quam adipiscing vitae proin sagittis nisl rhoncus. Duis at tellus at urna condimentum mattis pellentesque. Vivamus at augue eget arcu dictum varius duis at. Justo donec enim diam vulputate ut. Blandit libero volutpat sed cras ornare arcu. Ac felis donec et odio pellentesque diam volutpat commodo. Convallis a cras semper auctor neque. Tempus iaculis urna id volutpat lacus. Tortor consequat id porta nibh.

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Hac habitasse platea dictumst vestibulum rhoncus est pellentesque. Amet dictum sit amet justo donec enim diam vulputate ut. Neque convallis a cras semper auctor neque vitae. Elit at imperdiet dui accumsan. Nisl condimentum id venenatis a condimentum vitae sapien pellentesque. Imperdiet massa tincidunt nunc pulvinar sapien et ligula. Malesuada fames ac turpis egestas maecenas pharetra convallis posuere. Et ultrices neque ornare aenean euismod. Suscipit tellus mauris a diam maecenas sed enim. Potenti nullam ac tortor vitae purus faucibus ornare. Morbi tristique senectus et netus et malesuada. Morbi tristique senectus et netus et malesuada. Tellus pellentesque eu tincidunt tortor aliquam. Sit amet purus gravida quis blandit. Nec feugiat in fermentum posuere urna. Vel orci porta non pulvinar neque laoreet suspendisse interdum. Ultricies tristique nulla aliquet enim tortor at auctor urna. Orci sagittis eu volutpat odio facilisis mauris sit amet.

Tellus molestie nunc non blandit massa enim nec dui. Tellus molestie nunc non blandit massa enim nec dui. Ac tortor vitae purus faucibus ornare suspendisse sed nisi. Pharetra et ultrices neque ornare aenean euismod. Pretium viverra suspendisse potenti nullam ac tortor vitae. Morbi quis commodo odio aenean sed. At consectetur lorem donec massa sapien faucibus et. Nisi quis eleifend quam adipiscing vitae proin sagittis nisl rhoncus. Duis at tellus at urna condimentum mattis pellentesque. Vivamus at augue eget arcu dictum varius duis at. Justo donec enim diam vulputate ut. Blandit libero volutpat sed cras ornare arcu. Ac felis donec et odio pellentesque diam volutpat commodo. Convallis a cras semper auctor neque. Tempus iaculis urna id volutpat lacus. Tortor consequat id porta nibh.

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Hac habitasse platea dictumst vestibulum rhoncus est pellentesque. Amet dictum sit amet justo donec enim diam vulputate ut. Neque convallis a cras semper auctor neque vitae. Elit at imperdiet dui accumsan. Nisl condimentum id venenatis a condimentum vitae sapien pellentesque. Imperdiet massa tincidunt nunc pulvinar sapien et ligula. Malesuada fames ac turpis egestas maecenas pharetra convallis posuere. Et ultrices neque ornare aenean euismod. Suscipit tellus mauris a diam maecenas sed enim. Potenti nullam ac tortor vitae purus faucibus ornare. Morbi tristique senectus et netus et malesuada. Morbi tristique senectus et netus et malesuada. Tellus pellentesque eu tincidunt tortor aliquam. Sit amet purus gravida quis blandit. Nec feugiat in fermentum posuere urna. Vel orci porta non pulvinar neque laoreet suspendisse interdum. Ultricies tristique nulla aliquet enim tortor at auctor urna. Orci sagittis eu volutpat odio facilisis mauris sit amet.

Tellus molestie nunc non blandit massa enim nec dui. Tellus molestie nunc non blandit massa enim nec dui. Ac tortor vitae purus faucibus ornare suspendisse sed nisi. Pharetra et ultrices neque ornare aenean euismod. Pretium viverra suspendisse potenti nullam ac tortor vitae. Morbi quis commodo odio aenean sed. At consectetur lorem donec massa sapien faucibus et. Nisi quis eleifend quam adipiscing vitae proin sagittis nisl rhoncus. Duis at tellus at urna condimentum mattis pellentesque. Vivamus at augue eget arcu dictum varius duis at. Justo donec enim diam vulputate ut. Blandit libero volutpat sed cras ornare arcu. Ac felis donec et odio pellentesque diam volutpat commodo. Convallis a cras semper auctor neque. Tempus iaculis urna id volutpat lacus. Tortor consequat id porta nibh.

10 More Pages to Come in This Document. Get access to the complete answer.

MyAssignmenthelp.com commenced its journey with the purpose of relieving the students from their problems in writing essay ,assignment or dissertation and expanded through 3000+ experts. It is a chance for the students of Australia, UK and US to get superior quality academic writing help services without losing a huge chunk of money.

More COMP6300 COMP6300 Applied Cryptography: Questions & Answers

COMP5017 Data Structures and Algorithms

Task
Learning outcomes
Students will be able to understand1.1 Data structures1.2 The applications of data structures1.3 Object-oriented programming concepts1.4 Methods for program testing
Students will have acquired skills in:2.1 Data abstraction2.2 The use of data structures2.3 Programming at …

View Answer

Operating Systems Programming Project

In this SodaFountain, there are three SodaFlavors and two soda water tanks.In order to dispense a SodaFlavor:The SodaFountainServer must reserve the syrup tank for that flavor; andThe SodaFountainServer must reserve one of the soda water tanks.It doesn’t matter which soda water tank, as long a …

View Answer

COMP 1405 Introduction to Computer Science I

Question:
Pointillism is the name of a painting technique where patterns of coloured dots are used to form the coloured regions of an image. For this assignment, you will practice with looping control structures to create a program that can read in a source image and create a larger ‘new’ version …

View Answer

cs115 Computer Science

1.Briefly explain what is bad (exactly 1 weakness), though syntactically correct, about thefollowing code.const auto MAX_NUM_ANIMALS = 100;stringnames[MAX_NUM_ANIMALS];int ages[MAX_NUM_ANIMALS];int heights[MAX_NUM_ANIMALS];string favorite_foods[MAX_NUM_ANIMALS];Searching and Sorting(2 Marks) 2.Suppo …

View Answer

Content Removal Request

If you are the original writer of this content and no longer wish to have your work published on Myassignmenthelp.com then please raise the
content removal request.

Choose Our Best Expert to Help You

Still in Two Minds? The Proof is in Numbers!

33845 Genuine Reviews With a Rating of 4.9/5.

Management

Assignment: 12 Pages, Deadline:
2 days

I have been quite a good experience with your service. I got 70/100 grade on my result. However, the most important things that you can do are more cr …

User ID: 8***43 Singapore

Nursing

Assignment: 5 Pages, Deadline:
16 days

This was my last assignment for concepts and theories class and when I tell you using this site helped while I was in school and in between classes.

User ID: 6***42 United States

Healthcare

Essay: 6 Pages, Deadline:
12 days

Received a good grade for this particular assignment. It was on time and informative with the topic provided. Thank you.

User ID: 6***42 United States

Medical

Course Work: 4 Pages, Deadline:
6 days

Thanks it’s a great jobWaiting for the result from the teacherI will definitely deal with you in the coming days

User ID: 8***67 Belfast, Great Britain

Assignment

Essay: 2 Pages, Deadline:
7 hours

Amazing work done in spam of 6 hours. Great quality, best price. I have used this platform multiple times on all my english assignment and have always …

User ID: 8***85 Belfast, United States

Marketing

Home Work: 6 Pages, Deadline:
3 days

Good starting work for guidance – gives student time to revfine and add more input after understanding the framework/.

User ID: 8***39 Belfast, Malaysia

Finance

Home Work: 1 Page, Deadline:
14 days

Thank you so much! This was my first assignment which is I asked for help from here, and I will keep working with them. I’m so satisfied.

User ID: 8***99 Belfast, Austria

Assignment

Essay: 4.8 Pages, Deadline:
18 days

Amazing work, very happy. Will definitely recommend. Very precise, the topics very well presented. References in order, will have to wait until it wil …

User ID: 8***08 United Kingdom, Great Britain

Marketing

Thesis: 5 Pages, Deadline:
4 days

The work is legendary in every sense of the wordThank you, expert, for this wonderful work. Thank you for your effortIndeed, I am completely satisfied …

User ID: 9***3 United Kingdom, Kuwait

Statistics

Programming: 1.4 Pages, Deadline:
5 days

Excellent and very happy with the work. Would recommend to my friends and family.

User ID: 8***32 United Kingdom, Singapore

Management

Assignment: 7.6 Pages, Deadline:
9 days

Thank you very much for the good work and rework. I make this opportunity say happy new year for all of you and I would like to make use of service fu …

User ID: 7***46 United Kingdom, Saudi Arabia

Psychology

Home Work: 8 Pages, Deadline:
19 hours

It was perfect :); The answers are well structured. and as instructed, the work was submitted on time

User ID: 8***28 Malé, Maldives

Nursing

Essay: 6 Pages, Deadline:
3 days

Expert is nice and efficiency. Good communication with me and fast reply. Admin and call center is very helpful.

User ID: 2***16 Central, Hong Kong

It Write Up

Home Work: 1 Page, Deadline:
6 days

Didnt receive much marks. i dont know why. Maybe they didnt do well but that was just enouogh

User ID: 3***70 Central, Australia

Accounting

Course Work: 7 Pages, Deadline:
19 days

Happy with the outcome. Nice and easy to deal with and get started. delivered to timeframe and general expectations. Thank you and always a pleasure d …

User ID: 5***39 United Kingdom, Great Britain

Ancient History

Essay: 1 Page, Deadline:
9 days

thank you so much, work done on time, I appreciatedthank you so much to the person that did it

User ID: 4***45 United Kingdom, Australia

Management

Essay: 2 Pages, Deadline:
19 hours

Accepted assignment in short time. the expert is recommended. and definitely I will be back for other assignments.

User ID: 5***95 Basra, Iraq

Marketing

Home Work: 2 Pages, Deadline:
2 days

Thank you for taking the time do my assignment. Very good analysis and good use of the text but you seem to have information from other sources which …

User ID: 6***98 Basra, United States

Management

Assignment: 2 Pages, Deadline:
24 days

The author has answered all the questions properly, used straightforward language, provided meaningful references.

User ID: 3***61 Budapest, Hungary

Management

Assignment: 3 Pages, Deadline:
6 days

Very good piece of work, exactly what I needed. Everything was done very smooth from order to the end.

User ID: 5***28 London, Great Britain

Management

Assignment: 12 Pages, Deadline:
2 days

I have been quite a good experience with your service. I got 70/100 grade on my result. However, the most important things that you can do are more cr …

User ID: 8***43 Singapore

Nursing

Assignment: 5 Pages, Deadline:
16 days

This was my last assignment for concepts and theories class and when I tell you using this site helped while I was in school and in between classes.

User ID: 6***42 United States

Healthcare

Essay: 6 Pages, Deadline:
12 days

Received a good grade for this particular assignment. It was on time and informative with the topic provided. Thank you.

User ID: 6***42 United States

Medical

Course Work: 4 Pages, Deadline:
6 days

Thanks it’s a great jobWaiting for the result from the teacherI will definitely deal with you in the coming days

User ID: 8***67 Belfast, Great Britain

Assignment

Essay: 2 Pages, Deadline:
7 hours

Amazing work done in spam of 6 hours. Great quality, best price. I have used this platform multiple times on all my english assignment and have always …

User ID: 8***85 Belfast, United States

Marketing

Home Work: 6 Pages, Deadline:
3 days

Good starting work for guidance – gives student time to revfine and add more input after understanding the framework/.

User ID: 8***39 Belfast, Malaysia

Finance

Home Work: 1 Page, Deadline:
14 days

Thank you so much! This was my first assignment which is I asked for help from here, and I will keep working with them. I’m so satisfied.

User ID: 8***99 Belfast, Austria

Assignment

Essay: 4.8 Pages, Deadline:
18 days

Amazing work, very happy. Will definitely recommend. Very precise, the topics very well presented. References in order, will have to wait until it wil …

User ID: 8***08 United Kingdom, Great Britain

Marketing

Thesis: 5 Pages, Deadline:
4 days

The work is legendary in every sense of the wordThank you, expert, for this wonderful work. Thank you for your effortIndeed, I am completely satisfied …

User ID: 9***3 United Kingdom, Kuwait

Statistics

Programming: 1.4 Pages, Deadline:
5 days

Excellent and very happy with the work. Would recommend to my friends and family.

User ID: 8***32 United Kingdom, Singapore

Management

Assignment: 7.6 Pages, Deadline:
9 days

Thank you very much for the good work and rework. I make this opportunity say happy new year for all of you and I would like to make use of service fu …

User ID: 7***46 United Kingdom, Saudi Arabia

Psychology

Home Work: 8 Pages, Deadline:
19 hours

It was perfect :); The answers are well structured. and as instructed, the work was submitted on time

User ID: 8***28 Malé, Maldives

Nursing

Essay: 6 Pages, Deadline:
3 days

Expert is nice and efficiency. Good communication with me and fast reply. Admin and call center is very helpful.

User ID: 2***16 Central, Hong Kong

It Write Up

Home Work: 1 Page, Deadline:
6 days

Didnt receive much marks. i dont know why. Maybe they didnt do well but that was just enouogh

User ID: 3***70 Central, Australia

Accounting

Course Work: 7 Pages, Deadline:
19 days

Happy with the outcome. Nice and easy to deal with and get started. delivered to timeframe and general expectations. Thank you and always a pleasure d …

User ID: 5***39 United Kingdom, Great Britain

Ancient History

Essay: 1 Page, Deadline:
9 days

thank you so much, work done on time, I appreciatedthank you so much to the person that did it

User ID: 4***45 United Kingdom, Australia

Management

Essay: 2 Pages, Deadline:
19 hours

Accepted assignment in short time. the expert is recommended. and definitely I will be back for other assignments.

User ID: 5***95 Basra, Iraq

Marketing

Home Work: 2 Pages, Deadline:
2 days

Thank you for taking the time do my assignment. Very good analysis and good use of the text but you seem to have information from other sources which …

User ID: 6***98 Basra, United States

Management

Assignment: 2 Pages, Deadline:
24 days

The author has answered all the questions properly, used straightforward language, provided meaningful references.

User ID: 3***61 Budapest, Hungary

Management

Assignment: 3 Pages, Deadline:
6 days

Very good piece of work, exactly what I needed. Everything was done very smooth from order to the end.

User ID: 5***28 London, Great Britain

Have any Query?

GET HELP WITH YOUR HOMEWORK PAPERS @ 25% OFF

For faster services, inquiry about  new assignments submission or  follow ups on your assignments please text us/call us on +1 (251) 265-5102

Write My Paper Button

WeCreativez WhatsApp Support
We are here to answer your questions. Ask us anything!
👋 Hi, how can I help?
Scroll to Top