+ Started implementing the file encryption

+ File encryption

.gitignore

@@ -1 +1,3 @@
 config.inc.php
+example.enc.php
+example.dec.php

example-file.php

@@ -0,0 +1,26 @@
+<?php
+
+require("./lib.php");
+
+/**
+ * This is a simple example of how to encrypt files with the library
+ * The following code will read the file in chunks instead of loading
+ * the whole thing in memory, trying to keep the "Peak Memory Usage"
+ * as low as possible.
+*/
+
+define("INPUT_FILE",      "./example.php");
+define("OUTPUT_FILE",     "./example.enc.php");
+define("DEC_OUTPUT_FILE", "./example.dec.php");
+
+// Initialize the class
+$lib = new kpcrypt();
+
+// Encrypt the file
+$lib->encryptFile(INPUT_FILE, OUTPUT_FILE);
+
+// Decrypt the file as well
+$lib->encryptFile(OUTPUT_FILE, DEC_OUTPUT_FILE);
+
+echo "Errors: \n";
+print_r($lib->getErrors())

lib.php

@@ -14,6 +14,17 @@ class kpcrypt {
     // The key to use in the encryption process
     private $key = null;
 
+    /**
+    * Define the number of blocks that should be read from the source file for each chunk.
+    * For 'AES-128-CBC' each block consist of 16 bytes.
+    * So if we read 10,000 blocks we load 160kb into memory. You may adjust this value
+    * to read/write shorter or longer chunks.
+    */
+    private $blocks = 10000;
+
+    // A log of all of the errors, rather nice for debugging
+    private $errorLog = [];
+
     /**
      * @param string $key [Optional] The key to use for encryption, if none is mentioned a random one will be generated
      */
@@ -34,6 +45,30 @@ class kpcrypt {
         return $this->key;
     }
 
+    /**
+     * Get the encryption blocks for files
+     */
+    public function getEncryptionBlocks() {
+        return $this->blocks;
+    }
+
+    /**
+     * Redefine the encryption blocks size
+     */
+    public function setEncryptionBlocks(int $size = 10000) {
+        // Make sure the size has a minimum of blocks read.
+        if ( $size < 1 ) $size = 1;
+
+        // Set the local blocks
+        $this->blocks = $size;
+    }
+
+    public function getErrors() {
+        return $this->errorLog;
+    }
+
+    // #region String Encryption
+
         /**
          * @param string $data The data to be encrypted, this can only encrypt strings.
          * @param string $cipherMethod The cypher method to use in the encryption process, these can be checked using 
@@ -49,6 +84,7 @@ class kpcrypt {
             // Check if the encryption method is valid
             if (!in_array($cipherMethod, openssl_get_cipher_methods())) {
                 // Cypher was not in the available ciphers list.
+                $this->errorLog[] = "[" . __LINE__ . "]" . $cipherMethod . " isn't a valid cipherMethod.";
                 return FALSE;
             }
 
@@ -73,6 +109,7 @@ class kpcrypt {
                     return $encryptedData;
                 } else {
                     // Assign the output to the result
+                    $this->errorLog[] = "[" . __LINE__ . "]" . "Failed integrity check";
                     return FALSE;
                 }
             } else {
@@ -96,6 +133,7 @@ class kpcrypt {
             // Check if the encryption method is valid
             if (!in_array($cipherMethod, openssl_get_cipher_methods())) {
                 // Cypher was not in the available ciphers list.
+                $this->errorLog[] = "[" . __LINE__ . "]" . $cipherMethod . " isn't a valid cipherMethod.";
                 return FALSE;
             }
 
@@ -117,6 +155,70 @@ class kpcrypt {
             // Return the data
             return $data;
         }
+
+    // #endregion
+
+
+    // #region File Encryption
+
+        public function encryptFile(string $fileInput, string $fileOutput, string $cipherMethod = 'AES-256-CBC', bool $integrity_check = TRUE) {
+            // Lowercase the cipher
+            $cipherMethod = strtolower($cipherMethod);
+
+            // Check if the encryption method is valid
+            if (!in_array($cipherMethod, openssl_get_cipher_methods())) {
+                // Cypher was not in the available ciphers list.
+                $this->errorLog[] = "[" . __LINE__ . "]" . $cipherMethod . " isn't a valid cipherMethod.";
+                return FALSE;
+            }
+
+            // To encrypt a string   
+            $iv = openssl_random_pseudo_bytes(openssl_cipher_iv_length($cipherMethod));
+
+            // Try and open the destionation
+            if ( $fout = fopen($fileOutput, 'w') ) {
+                // Try and open the input file
+                if ($fin = fopen($fileInput, 'rb') ) {
+                    // Place the IV at the beginning of the file for later decryption
+                    fwrite($fout, $iv);
+
+                    // Start reading from the input file
+                    while ( !feof($fin) ) {
+                        // Read in blocks of 16
+                        $plaintext = fread($fin, 16 * $this->blocks);
+                        $ciphertext = openssl_encrypt($plaintext, $cipherMethod, $this->key, OPENSSL_RAW_DATA, $iv);
+                        // Use the first 16 bytes of the ciphertext as the next initialization vector
+                        $iv = substr($ciphertext, 0, 16);
+                        fwrite($fout, $ciphertext);
+                    }
+
+                    // Close the input file
+                    fclose($fin);
+
+                } else {
+                    $this->errorLog[] = "[" . __LINE__ . "]" . "Could not open input file for reading.";
+                    // Close the output file
+                    fclose($fout);
+                    return false;
+                }
+
+            } else {
+                $this->errorLog[] = "[" . __LINE__ . "]" . "Could not open file output path for writing.";
+                return false;
+            }
+
+
+            // Close the output file
+            fclose($fout);
+            return 1;
+        }
+
+        public function decryptFile(string $fileInput, string $fileOutput, string $cipherMethod = 'AES-256-CBC') {
+
+        }
+
+    // #endregion
+
 }