[DEV] Add Vigenere Abstract;

Author: amculin

source/VigenereCipherBlueprint.php

@@ -0,0 +1,222 @@
+<?php
+namespace amculin\cryptography\classic;
+
+use amculin\cryptography\classic\enums\ProcessType;
+
+abstract class VigenereCipherBlueprint
+{
+    /**
+     * Default list of acceptable character to be used in vigenere cipher algorithm
+     * By default, it just an alphabetical list.
+     *
+     * @var string
+     */
+    public $tabulaRecta;
+
+    /**
+     * The current process whether it is encrypt or decrypt
+     *
+     * @var string
+     */
+    public $process;
+
+    /**
+     * The plain text/message to be encrypted
+     *
+     * @var string
+     */
+    public $plainText;
+
+    /**
+     * The key used to encrypt plain text/message
+     *
+     * @var string
+     */
+    public $key;
+
+    /**
+     * The cipher text to be decrypted
+     *
+     * @var string
+     */
+    public $cipherText;
+
+    public function __construct(string $process = 'encrypt', string $data = null, string $key = null)
+    {
+        $this->setProcess($process);
+
+        if ($process == ProcessType::ENCRYPT->value) {
+            if (! is_null($data) && ! is_null($key)) {
+                $this->setPlainText($data);
+                $this->setKey($key);
+                $this->encrypt();
+            }
+        } else {
+            if (! is_null($data) && ! is_null($key)) {
+                $this->setCipherText($data);
+                $this->setKey($key);
+                $this->decrypt();
+            }
+        }
+    }
+
+    /**
+     * Method to get current process
+     *
+     * @return string
+     */
+    public function getProcess(): string
+    {
+        return $this->process;
+    }
+
+    /**
+     * Set the current process
+     *
+     * @param string process
+     * @return void
+     */
+    public function setProcess(string $process): void
+    {
+        $this->process = $process;
+    }
+
+    /**
+     * Method to get plain text
+     *
+     * @return string
+     */
+    public function getPlainText(): string
+    {
+        return $this->plainText;
+    }
+
+    /**
+     * Set the plain text/message/data to be encrypted
+     *
+     * @param string message
+     * @return void
+     */
+    public function setPlainText(string $plainText): void
+    {
+        $this->plainText = $plainText;
+    }
+
+    /**
+     * Method to get key
+     *
+     * @return string
+     */
+    public function getKey(): string
+    {
+        return $this->key;
+    }
+
+    /**
+     * Set the key to be be used in encryption/decryption process
+     *
+     * @param string key
+     * @return void
+     */
+    public function setKey(string $key): void
+    {
+        $paddedKey = $this->generateKey($key);
+
+        $this->key = $paddedKey;
+    }
+
+    /**
+     * Method to get cipher text
+     *
+     * @return string
+     */
+    public function getCipherText(): string
+    {
+        return $this->cipherText;
+    }
+
+    /**
+     * Set the cipher text result from encryption process
+     *
+     * @param string message
+     * @return void
+     */
+    public function setCipherText(string $cipherText): void
+    {
+        $this->cipherText = $cipherText;
+    }
+
+    /**
+     * Method to generate the key
+     * We loop the key then concatenate it until it has the same length with the plain text
+     * Example:
+     *     Plain text: vigenerecipher (14 characters)
+     *     Key: abcd (4 characters)
+     *     Repeated key: abcdabcdabcdab (14 characters)
+     *
+     * @param string key
+     * @return string
+     */
+    public function generateKey(string $key): string
+    {
+        $keyLength = strlen($key);
+        $messageLength = strlen($this->process == ProcessType::ENCRYPT->value ? $this->plainText :
+            $this->cipherText);
+
+        $repeatTimes = floor($messageLength / $keyLength);
+        $paddingKeyLength = $messageLength - ($keyLength * $repeatTimes);
+        
+        $repeatedKey = '';
+
+        for ($i = 0; $i < $repeatTimes; $i++) {
+            $repeatedKey .= $key;
+        }
+        
+        return $repeatedKey . substr($key, 0, $paddingKeyLength);
+    }
+
+    /**
+     * Method to encrypt the plain text
+     *
+     * @return void
+     */
+    public function encrypt(): void
+    {
+        $messageLength = strlen($this->plainText);
+        $cipher = '';
+        
+        for ($i = 0; $i < $messageLength; $i++) {
+            $messageCharPosition = strpos($this->tabulaRecta, substr($this->plainText, $i, 1));
+            $keyCharPosition = strpos($this->tabulaRecta, substr($this->key, $i, 1));
+            
+            $shift = $messageCharPosition + $keyCharPosition;
+            $cipherCharPosition = $shift % strlen($this->tabulaRecta);
+            $cipher .= substr($this->tabulaRecta, $cipherCharPosition, 1);
+        }
+
+        $this->setCipherText($cipher);
+    }
+
+    /**
+     * Method to decrypt the cipher text
+     *
+     * @return void
+     */
+    public function decrypt(): void
+    {
+        $messageLength = strlen($this->cipherText);
+        $plain = '';
+        
+        for ($i = 0; $i < $messageLength; $i++) {
+            $messageCharPosition = strpos($this->tabulaRecta, substr($this->cipherText, $i, 1));
+            $keyCharPosition = strpos($this->tabulaRecta, substr($this->key, $i, 1));
+            
+            $shift = $messageCharPosition - $keyCharPosition;
+            $plainCharPosition = $shift % strlen($this->tabulaRecta);
+
+            $plain .= substr($this->tabulaRecta, $plainCharPosition, 1);
+        }
+        
+        $this->setPlainText($plain);
+    }
+}