Add subdirectory for cryptography examples

+ Add example using columnar transposition for encrypting / decrypting messages
+ Fix cmake build error from duplicate lib-bst when building from project root
This commit is contained in:
Shaun Reed 2021-07-20 11:21:59 -04:00
parent 23c4f0e491
commit c8683680dd
7 changed files with 304 additions and 3 deletions

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@ -19,6 +19,7 @@ project(
add_subdirectory(algorithms)
add_subdirectory(cmake)
add_subdirectory(cryptography)
add_subdirectory(datastructs)
add_subdirectory(graphics)
add_subdirectory(patterns)

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@ -15,7 +15,7 @@ project (
LANGUAGES CXX
)
add_library(lib-bst "bst.cpp")
add_library(lib-bst-algo "bst.cpp")
add_executable(test-bst "driver.cpp")
target_link_libraries(test-bst lib-bst)
add_executable(test-bst-algo "driver.cpp")
target_link_libraries(test-bst-algo lib-bst)

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@ -0,0 +1,18 @@
###############################################################################
## Author: Shaun Reed ##
## Legal: All Content (c) 2021 Shaun Reed, all rights reserved ##
## About: A root project for practicing cryptography in C++ ##
## ##
## Contact: shaunrd0@gmail.com | URL: www.shaunreed.com | GitHub: shaunrd0 ##
##############################################################################
#
cmake_minimum_required(VERSION 3.15)
project (
#[[NAME]] Cryptography
VERSION 1.0
DESCRIPTION "A project for practicing cryptography in C++"
LANGUAGES CXX
)
add_subdirectory(columnar-transposition)

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@ -0,0 +1,22 @@
################################################################################
## Author: Shaun Reed ##
## Legal: All Content (c) 2021 Shaun Reed, all rights reserved ##
## About: A root project for practicing columnar transposition cipher in C++ ##
## ##
## Contact: shaunrd0@gmail.com | URL: www.shaunreed.com | GitHub: shaunrd0 ##
################################################################################
#
cmake_minimum_required(VERSION 3.15)
project(
#[[NAME]] ColumnarTransposition
VERSION 1.0
DESCRIPTION "Practice implementing columnar transposition in C++"
LANGUAGES CXX
)
add_library(lib-cipher "lib-cipher.cpp")
add_executable(columnar-transposition-test "driver.cpp")
target_link_libraries(columnar-transposition-test lib-cipher)

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@ -0,0 +1,85 @@
/*##############################################################################
## Author: Shaun Reed ##
## Legal: All Content (c) 2021 Shaun Reed, all rights reserved ##
## About: An example of using columnar transposition cipher ##
## + Using concept at www.braingle.com/brainteasers/codes/columnartrans.php ##
## ##
## Contact: shaunrd0@gmail.com | URL: www.shaunreed.com | GitHub: shaunrd0 ##
################################################################################
*/
#include "lib-cipher.hpp"
#include<iostream>
// Columnar transposition cipher
// https://www.braingle.com/brainteasers/codes/columnartrans.php#form
// NOTE: Must check the 'irregular case' box to produce same results
// + I only used the irregular case to encrypt and decrypt
// + I did not write any code for testing with the regular case
/******************************************************************************/
// Main program loop
int main (const int argc, const char * argv[]) {
// Left some test cases I used commented out :)
// Using example keyword from www.braingle.com
// + The embedded example there doesn't seem to support numbers in keywords :(
CipherData cData("ZEBRAS");
// Taking user input for keyword using CipherData ctor
// CipherData cData;
int choice = 0;
bool exit = false;
std::string message; // Message to encrypt or decrypt
while (!exit) {
std::string result;
switch (choice) {
case 1:
std::cout << "\nEncrypting...\n";
// Encrypt example from www.braingle.com
result = cData.Encrypt("WEAREDISCOVEREDFLEEATONCE");
// Take input for encrypting a message
// result = cData.Encrypt();
std::cout << "Encrypted message: " << result << std::endl;
exit = true;
break;
case 2:
std::cout << "\nDecrypting...\n";
// Encrypt, decrypt example from www.braingle.com
result = cData.Decrypt(cData.Encrypt("WEAREDISCOVEREDFLEEATONCE"));
// Take input for previously encrypted message to decrypt
// result = cData.Decrypt();
std::cout << "Decrypted message: " << result << std::endl;
exit = true;
break;
default:
std::cout << "What would you like to do?\n1. Encrypt\n2. Decrypt\n";
// Take input, handle it accordingly
// + https://www.cplusplus.com/forum/general/207458/
if (!(std::cin >> choice)) {
std::cout << "Invalid character input, choose an option below\n";
}
else if (choice != 1 && choice != 2) {
std::cout << "Incorrect option entered (" << choice << ")\n";
}
std::cin.clear();
std::cin.ignore();
break;
}
}
return 0;
}

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@ -0,0 +1,127 @@
/*##############################################################################
## Author: Shaun Reed ##
## Legal: All Content (c) 2021 Shaun Reed, all rights reserved ##
## About: An example of using columnar transposition cipher ##
## + Using concept at www.braingle.com/brainteasers/codes/columnartrans.php ##
## ##
## Contact: shaunrd0@gmail.com | URL: www.shaunreed.com | GitHub: shaunrd0 ##
################################################################################
*/
#include "lib-cipher.hpp"
// Initializes orderVect to determine order columns should be used
void CipherData::InitOrder(std::string temp)
{
// Create a temp value sorted lexicographically, remove duplicate characters
// https://en.cppreference.com/w/cpp/string/basic_string/operator_cmp
std::sort(temp.begin(), temp.end());
auto it = std::unique(temp.begin(), temp.end());
temp.erase(it, temp.end());
// Step through each character in lexicographic order
for (int i = 0; i < temp.size(); i++) {
// Check each character in the keyWord for the current lexicographic char
for (int j = 0; j < keyWord_.size(); j++) {
// If they are equal, push the index of the char in keyWord to orderVect
if (keyWord_[j] == temp[i]) {
orderVect_.push_back(j);
}
}
}
}
// Allows getting keyWord when using CipherData default ctor
std::string CipherData::GetKey()
{
std::string key;
std::cout << "Enter the keyword: ";
std::getline(std::cin, key);
std::cout << "Keyword entered: " << key << std::endl;
return key;
}
// Transpose a character matrix, using a vector of strings
void CipherData::Transpose(const std::vector<std::string> &in,
std::vector<std::string> &out)
{
int cols = in[0].size();
// JIC some other row is larger than the first
for (const auto &row : in) cols = (row.size() > cols) ? row.size() : cols;
int rows = in.size();
out.resize(cols);
for (int i = 0; i < cols; i++) {
for (int j = 0; j < rows; j++) {
if (in[j].size() <= i) continue;
out[i] += in[j][i];
}
}
}
std::string CipherData::Encrypt(std::string message)
{
// If no message was provided, ask for one
if (message.empty()) {
std::cout << "Input message to encrypt: ";
std::getline(std::cin, message);
std::cout << "Encrypting message \"" << message << "\"\n";
}
std::string encryptedMessage;
std::vector<std::string> rows;
// Split the message into rows equal to the length of our keyWord
for (size_t i = 0; i < message.size(); i+=keyWord_.size()) {
std::string substr = message.substr(i, keyWord_.size());
rows.push_back(substr);
}
// Transpose the matrix of characters
std::vector<std::string> transposed;
Transpose(rows, transposed);
// Append each row of the transposed matrix to our encryptedMessage
for (const auto &val : orderVect_) encryptedMessage += transposed[val];
return encryptedMessage;
}
std::string CipherData::Decrypt(std::string message)
{
// If no message was provided, ask for one
if (message.empty()) {
std::cout << "Input message to decrypt: ";
std::getline(std::cin, message);
std::cout << "Decrypting message \"" << message << "\"\n";
}
std::string result;
std::vector<std::string> rows;
// Split the message into rows equal to the length of our keyWord
int rowLength = message.size() / keyWord_.size();
// If dividing message and keyword size has a remainder N
// + There will be N rows with +1 characters
int fullRows = message.size() % keyWord_.size();
rows.resize(orderVect_.size());
// Track the ending position after each substring is taken
int lastPos = 0;
for (int i = 0; i < orderVect_.size(); i++) {
// If we are assigning to any row < fullRows, it should have + 1 character
if (orderVect_[i] < fullRows) {
rows[orderVect_[i]] = message.substr(lastPos, rowLength + 1);
lastPos += rowLength + 1;
}
else {
rows[orderVect_[i]] = message.substr(lastPos, rowLength);
lastPos += rowLength;
}
}
std::vector<std::string> transposed;
Transpose(rows, transposed);
for (const auto &row : transposed) result += row;
return result;
}

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@ -0,0 +1,48 @@
/*##############################################################################
## Author: Shaun Reed ##
## Legal: All Content (c) 2021 Shaun Reed, all rights reserved ##
## About: An example of using columnar transposition cipher ##
## + Using concept at www.braingle.com/brainteasers/codes/columnartrans.php ##
## ##
## Contact: shaunrd0@gmail.com | URL: www.shaunreed.com | GitHub: shaunrd0 ##
################################################################################
*/
#ifndef COLUMNARTRANSPOSITION_LIB_CIPHER_HPP
#define COLUMNARTRANSPOSITION_LIB_CIPHER_HPP
#include <iostream>
#include<algorithm>
#include<vector>
/******************************************************************************/
// CipherData struct to hold data and methods related to encrypting / decrypting
struct CipherData {
// Can't create this object without providing a keyWord to initialize order
explicit CipherData(std::string keyWord) : keyWord_(std::move(keyWord))
{
InitOrder(keyWord_);
}
CipherData() : keyWord_(GetKey()) { InitOrder(keyWord_);}
/****************************************************************************/
// Member functions
// Initializes orderVect, pass by value to create local copy of keyWord
void InitOrder(std::string temp);
static std::string GetKey();
static void
Transpose(const std::vector<std::string> &in, std::vector<std::string> &out);
// Default values for param allows calling with no message
std::string Encrypt(std::string message="");
std::string Decrypt(std::string message="");
private:
std::string keyWord_;
std::vector<int> orderVect_;
};
#endif // COLUMNARTRANSPOSITION_LIB_CIPHER_HPP