CMPE102: Fall 2021 Program #4: You are responsible to write an assembly function for an encryption library. This function will encrypt or decrypt a string of characters.

INSTRUCTIONS TO CANDIDATES

ANSWER ALL QUESTIONS

First copy/rename encrypt_sample.cpp to encrypt.cpp

MacOS Terminal: gcc -fdeclspec -c encrypt.cpp gcc -shared -o libencrypt.so encrypt.o gcc -L. -o p4 p4.cpp -lencrypt Windows Command Prompt: gcc -c encrypt.cpp gcc -shared -o libencrypt.dll encrypt.o gcc -L. -o p4.exe p4.cpp -lencrypt

The first command compile encrypt.cpp into encrypt.o; the second command "link" encrypt.o into shared lib libencrypt.so; the third command compile/link p4.cpp into p4; To run the program (will take either 2 or 4 parameters): Mac - ./p4 "Frank Butt" 0 OR ./p4 "Frank Butt" 0 1 5 Windows - p4 "Frank Butt" 0R p4 "Frank Butt" 0 1 5

 

 

CMPE102: Fall 2021

Program #4: Encryption Library 

 

 

Description:

 

You are responsible to write an assembly function for an encryption library.  This function will encrypt or decrypt a string of characters.  It will use a simple ciphertext algorithm which do character shifting. This function will use the C function signature but everything within this function should be assembly code using the ASM block similar to the assembly example shown in class.  This function should be built into a separate shared library (e.g. DLL).  p4.cpp will contain the calling function and should not be modified.

 

Program Specification:

 

long s_encrypt (char *src, char* dest, long en_flag);

 

  src – the original string

 

  dest – the output string

 

  en_flag – 0 for encryption and 1 for decryption

 

This function returns the # of characters being changed in the string.  If no change, it should return zero.

 

Additional Information:

 

- We only apply the change algorithm for (‘A’..‘Z’ to ‘a’..’z’).  Other characters are left unchanged.

- All the alpha characters will toggle between upper and lower case.

- The input and output string are displayed on the screen.

- You MUST have detailed comments within the _asm block for your algorithm.

- We will use a separate header file (key.h) for the default character shifting algorithm attributes.

- In key.h, you have 2 global variables within the DLL which can be updated via set/get functions. 

long direction  = 0;  /* 0 means forward, 1 means backward */

      long shiftcount = 2;  /* number of character to shift */

Program Checklist:

 

You must submit files named encrypt.cpp and readme.p4 file.  The rest of the files must be left unchanged or your program will fail our tests. 

 

Attachments:

Related Questions

. Introgramming & Unix Fall 2018, CRN 44882, Oakland University Homework Assignment 6 - Using Arrays and Functions in C

DescriptionIn this final assignment, the students will demonstrate their ability to apply two ma

. The standard path finding involves finding the (shortest) path from an origin to a destination, typically on a map. This is an

Path finding involves finding a path from A to B. Typically we want the path to have certain properties,such as being the shortest or to avoid going t

. Develop a program to emulate a purchase transaction at a retail store. This program will have two classes, a LineItem class and a Transaction class. The LineItem class will represent an individual

Develop a program to emulate a purchase transaction at a retail store. Thisprogram will have two classes, a LineItem class and a Transaction class. Th

. SeaPort Project series For this set of projects for the course, we wish to simulate some of the aspects of a number of Sea Ports. Here are the classes and their instance variables we wish to define:

1 Project 1 Introduction - the SeaPort Project series For this set of projects for the course, we wish to simulate some of the aspects of a number of

. Project 2 Introduction - the SeaPort Project series For this set of projects for the course, we wish to simulate some of the aspects of a number of Sea Ports. Here are the classes and their instance variables we wish to define:

1 Project 2 Introduction - the SeaPort Project series For this set of projects for the course, we wish to simulate some of the aspects of a number of