[Solved] COMP3353 Project #5

• Read the design section and write a program. Submit source file .asm to Canvas.
• Please start early. ZERO point for late submission. After the 11:59pm on the due day, you cant submit your assignment anymore.

Deliverables:

• Save your source of assembly program as a .asm file.
• Name document of source code as a Firstname_Lastname.asm.
• (5 points) At the top of your .asm file, give a brief description of the program, an author namand the the thlast modified date in the form of comments. e
• (15 points) A screenshot of the result after you compile and run program, correctly demonstrate the decryption result of the input JPUESZSBAPANNHTXRTLBVLL. The screenshot file should be named as Firstname_Lastname.png or Firstname_Lastname.jpg or any other valid picture format suffix.
• Submit your Firstname_Lastname.asm and Firstname_Lastname.png through the Canvas system.

Rebuttal period:

• You will be given a period of 3 business days to read and respond to the comments and grades of your homework or project assignment. The TA may use this opportunity to address any concern and question you have. The TA also may ask for additional information from you regarding your homework or project.

Objective:

This program has two objectives. The first objective is to create a procedure that will take plaintext and an encryption key, use the Vigenre cipher, and encrypt the plaintext. The second objective is to create a procedure that will take cypher-text, an encryption key, use the Vigenre cipher, and decrypt the cypher-text.

Assume that all characters will be uppercase letters, no spaces, symbols, etc.

All high level directives are not allowed on this homework. (e.g. .IF .ENDIF .REPEAT, etc)

Design:

Create a BYTE array with the label input. This array may be of any length between 2 and 100. In the case of encryption input will hold the plaintext and in the case of decryption input will hold cypher-text.

Create a BYTE array with the label key. This array will have length between 1 and (LENGHTOF input -1). Meaning the lower bound for key is one character and the upper bound is one less than the number of characters in input.

Create a BYTE variable named options. This variable will be used to determine which procedures should be executed. If options contain the value 1 it means the program should execute encryption procedure. If options contain the value 0 (or any other value than 1) the program should execute decryption procedure.

Create a BYTE array with the label output. This array will have a dynamic length equal to

LENGTHOF input. When executing the program using encryption, the variable output will hold the cypher-text and in the case of decryption, output will hold plaintext.

You may create any other values you deem necessary.

You must have three procedures for this homework. The main procedure, a procedure to handle encryption, and another to handle the decryption. You may create other procedures if you wish.

Example of encryption / decryption:

For more information check the Wiki link: (https://en.wikipedia.org/wiki/Vigen%C3%A8re_cipher)

The example below will use the plaintext word MEMORY and the key BAD.

First you line up your plaintext word with your key by writing the key directly beneath the plaintext word. Continue to repeat the key under each plaintext character:

MEMORY

BADBAD

In the above example MEMORY is longer than BAD, therefore, BAD was repeated. Next choose each character in the plaintext word, starting with the first and encrypt it.

To encrypt a character, you first find the column on the chart corresponding to the character in the plaintext, e.g. the character M (circled in red). Next, find the row starting with the key character, e.g. the character B (circled in red). Finally, find where the plaintext column and the key row intersect, e.g. the character N (circled in red). Continue this for each character.

MEMORY

BADBAD

MEMORY

BADBAD

MEMORY

BADBAD

Continue until all characters have been encrypted:

Input = MEMORY (plaintext) Key = BADBAD (key) output= NEPPRB (cypher-text)

Decrypting is the opposite of encrypting. To decrypt NEPPRB first write the key under the cyphertext. Then find the row starting with the key character. Next, move across that row until you find the cypher-text character. The cypher-text characters column is the plaintext column.

NEPPRB

BADBAD

NEPPRB

BADBAD

NEPPRB

Continue until the cypher-text has been decrypted:

Input = NEPPRB

Key = BADBAD

Output = MEMORY

): Read the comments in the template file project5_template.asm and finish (1) (8)

For the code, explain what each assembly line means in plain English. Your comment should be meaningful and reflect the code correctly.