Administrative Information | Covers Concepts From | Chapter 8 (and other material) |
| Date Assigned | Thursday, October 7, 2021 |
| Date / Time Due | Saturday, October 16, at 11:59 pm. End/late date is Monday, October 18, at 11:59 pm. Note that it is HIGHLY RECOMMENDED that you watch my video on HOW TO USE THE Vigenre Square AND my video on HOW TO PERFORM RSA ENCRYPTION before doing this assignment. Submissions uploaded between the due date and the late/end date are subject to deductions specified in the syllabus |
| Method of Submission | Download this document, enter your answers directly into it, and upload it back into Folio. This assignment must be submitted via Folio no other method will be accepted |
| Percentage of overall grade | 5% of the overall grade, or 50 points out of 1000. |
| Value of each question | See each question or component |
| BONUS | See below |
DO NOT DELETE ANY ADMIN INFO or QUESTIONS. SUBMISSIONS WITH ANY ORIGINAL MATERIAL THAT IS DELETED WILL NOT BE GRADED. In this assignment, you will encrypt (not decrypt) a message by hand, using techniques used from the Whitman/Mattord Principles of Information Security online pdf file and lectures. This assignment is graded on percentages of 100. So, for example, if you earn 84%, your score is 42 out of 60. Using the same score of 84%, if you earn the 6% extra credit, now your score is 90% of 60 = 54. Consult the table below for the percentage value of each question and each questions components.
| Question / Component | Value |
| RSA Encryption | |
| Table A | 4% |
| Table B | 6% |
| Table C | 2% |
| Table D | 2% |
| Table E | 2% |
| Each encrypted ciphertext: 7 x 3 each | 21% |
| TOTAL RSA Encryption | 37% |
| |
| 2. Vernam | 12% |
| 3. Vigenre | 14% |
| 4. XOR | 11% |
| 5. Caesar | 6% |
| |
| Hashing | |
| Hashing results, 6 x 1 each | 6% |
| Hashing answer to a. | 4% |
| Hashing answer to b. | 4% |
| Hashing answer to c. | 6% |
| TOTAL Hashing | 20% |
| ALL TOTAL | 100% |
1 This question has two parts.
First, given two prime numbers less than 50, you will derive the E and the D for them, as described in the class, in the text, and in the PowerPoint. You will also give the public key (proven to work) to encrypt the message. It is not necessary to decrypt the encrypted message, so you even though you will determine the D, you wont be using it.
Second, you will encrypt a message
on the next page. All of this can be done by hand, i.e. using (1) a calculator, (2) the web page provided to you in the PowerPoint, and (3) the pages from the Whitman/Mattord text. For the calculator, you will need the
Scientific View of the calculator in Windows (I presume Mac has an equivalent).
Note that the number 2 is always a prime number. The number 1 is NOT a prime number. Given
P = 13 and
Q = 29 In each right column entry of the table, you MUST show your work. Just providing the result will give you zero points. You MUST use the link
RSA-Step-by-Step to the website from CrypTool in the Chapter 08 Learning Module.
| A | Compute n = pq | |
| B | Compute the totient of the product, ?n | |
| I will give you your e | 19 |
| C | What is d? (from the website) | |
| D | What is the public key? Write it as (n = , e = ) | |
| E | Even though you wont use it, what is the private key? Write it as (n = , d = ) | |
| Extra | Answer this question for 6 points extra credit: are there any prime numbers | |
USING THE RSA-STEP-BY-STEP PAGE IN CRYPTOOL. AT THE END OF THIS DOCUMENT, OR IN ANOTHER WORD DOCUMENT, COPY AND PASTE THE IMAGES OF THE SECRET KEY, D, AND AN ATTEMPT AT THE BOTTOM OF THE PAGE TO ENCRYPT A NUMERIC MESSAGE. FAILURE TO DO SO WILL COST YOU 3% OF YOUR SCORE Now, on the next page, you will use the information above to encrypt a message, as depicted in the Adobe pdf file from the Whitman/Mattord text. Principles of Information Security, 4
th ed.
Encrypt the message
SENDGOLD (no spaces) using the following public key (proven to work): See Table 8-5 in the Adobe pdf example from the Whitman/Mattord text.
Note the different P, Q, and (N,E) than in the Adobe pdf example from the Whitman/Mattord text. Make sure you associate each letter of the alphabet with its ordinal number, so A = 1, B = 2, C = 3, etc.
Remember that your P = 13, Q = 29,
and the public key you derived above. The message is broken into two tables so it will fit.
READ THIS: Your encrypted values
must include leading zeroes to the third digit. So, for example, if your ciphertext results in
83, you
must code it as
083 if you do not do this, that particular encrypted value will be counted as incorrect. | Message | S | E | N | D |
| Text Numeric Value (TNV) | | | | |
| Ciphertext | | | | |
| Message | G | O | L | D |
| Text Numeric Value (TNV) | | | | |
| Ciphertext | | | | |
Since D is included twice in the message, the value of this part is 7 answers (not eight) x 3% each = 21% of the assignment. You must get each of the two elements per letter correct for the entire letter column to be scored.
All or nothing. 2. Using a somewhat lengthier version of the message in the RSA section, and the Vernam Cipher depicted on page 362 in the Adobe pdf example from the Whitman/Mattord text, produce the correct ciphertext.
Answers in the after modulo subtraction row should be left blank if not required. | Plaintext message | S | E | N | D | C | A | S | H | N | O | W |
| One-time pad | H | L | R | M | O | N | Z | L | O | P | Q |
| Sum | 26 | 21 | 31 | 23 | 18 | 20 | 43 | 18 | 39 | 33 | 35 |
| After Modulo Subtraction | | | 05 | | | | 17 | | 13 | 07 | 09 |
| Ciphertext | Z | U | E | W | R | T | Q | R | M | G | I |
3. Using the Vigenre Square (either from the PowerPoint or the Whitman/Mattord Adobe pdf file its the same square) and the keyword
SECURITY, encrypt the same message as above (note that since the plaintext only has 11 letters, we drop the 5 letters of the key after the first 3 letters).
| S | E | C | U | R | I | T | Y | S | E | C |
| S | E | N | D | C | A | S | H | N | O | W |
| | | | | | | | | | |
4. Using Exclusive OR (XOR) with the characters
Bag in ASCII binary as the
key, and the word
DOG as your
plaintext, create the sequence of cipher bits.
NOTE the key IS case-sensitive. NOTE: you have to determine the ASCII for
BOTH the key
(Bag) and the plaintext
(DOG). You must enter the ASCII for each before doing the XOR function. The ASCII values for each can be determined from the slide in the
Katz-02B-Binary-Text PowerPoint provided online. Cells are colored above to indicate the separation of bits between the three letters. 5
The Caesar Cipher. The CrypTool site has all sorts of ciphers. Click on the link
CrypTool all cryptographic tools, find Caesar, and click on it.
- You are given the input message: Hello, this is a test. Please enter your text here. Remove this entire message and replace it with Georgia Southern University.
- You are also given an output message. Do the following:
- Change the Key to 5
- Click on Blocks of 5
- Leave keep non-alphabet characters checked
JUST COPY AND PASTE THE TEXT. DO NOT COPY AND PASTE AN IMAGE. Copy and paste the result
here 6.
Hashing. You will use an online hash generator to compare the differences between a slight change in the same sentence, with three different hashing algorithms. Input sentence will be:
Cryptography is important to Security First you will generate the hash of that sentence
without a period at the end of it (as it is written above). Then you will input the same sentence,
but with a period at the end of it. Note that in the word
Cryptography and the word
Security,
C and
S must be
uppercase. Click on the link to the
Online Hash Calculator This site is also provided to you as a link in the Chapter 8 Learning Module (folder)
| Hash Algorithm | With or without period | Result |
| md-5 | Without period | |
| md-5 | With period | |
| Sha-1 | Without period | |
| Sha-1 | With period | |
| Sha-256 | Without period | |
| Sha-256 | With period | |
a. You tried three different algorithms with the same message, except that for each algorithm, one version of the message did not have a period at the end, and one version did have a period at the end. Given your results for each algorithm, and what we discussed in class, there are
TWO things you can say about the results from each algorithm. What are they? Choose
TWO of the following: a. For
each algorithm, the result with the period was identical to the result without the period b. For
each algorithm, regardless of the length of the
input message (period or no period), the length of the
output result (number of characters) was always the
same c. Regardless of the length of the
input message (period or no period), for
each algorithm, the length of the
output result (number of characters) was
different d Just adding one character, even something as small as a period, creates a totally different output hash e There was no difference in length of output between any two or three different algorithms (e.g. md-5 vs. Sha-1)
ANSWER (S): b. Look up the
difference between SHA-1 and SHA-256 online. Given your results, what can you say about
the differences between these two algorithms, regardless of whether you placed a period at the end of the sentence or not? Include in your answer the security implications of using the two algorithms. c. Since hashing is not used for encryption (it is a one-way algorithm and cannot be decrypted), explain
HOW it is used
WITH encryption to ensure the authenticity of a
digital signature.
