Changes revert

LICENSE

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+MIT License
+
+Copyright (c) 2022 Václav Šmejkal
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

Makefile

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+all: main
+
+# Main file
+files = src/test/main.c
+
+# Source files
+files += src/*.c
+
+# Header files
+files += include/*.h
+
+main:
+	@echo Compiling...
+	cc $(files) -lm -o out/why2

README.md

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+# WHY2 Encryption System
+
+*Yeah.*
+
+This project is made 'like a library', so compiling is useless... :)
+
+### Table of contents
+
+  - [Using in Your projects](#using-in-your-projects)
+  - [Example of code](#example-of-code)
+  - [Example programs](#example-programs)
+
+## Using in Your projects 
+
+To **encrypt** text, use function `encryptText()` from file `include/encrypter.h`.
+
+To **decrypt** text, use function `decryptText()` from file `include/decrypter.h`.
+
+Jump to [examples](#examples) if you're not sure, how to use.
+
+## Example of code
+
+- Encryption:
+    ```c
+    //FIRST VARIANT
+    char *yourText = encryptText("Put here text, you want encrypt...", "tzXlZGxkhfYOvRthqokDrmGFyDMylgmeIlrJTpVAwuqrLjABXM"); //The second thing is Your **key**. (The key must be 50 characters long!)
+
+    //SECOND VARIANT
+    char *yourText = encryptText("Put here text, you want encrypt...", NULL); //See? You don't have to use Your key. Program will automatically generate one for you. It will be printed out, so save it somewhere.
+    ```
+
+- Decryption:
+    ```c
+    char *yourText = decryptText("158.-83.9388.-14.57.8419.113.-98.10576", "tzXlZGxkhfYOvRthqokDrmGFyDMylgmeIlrJTpVAwuqrLjABXM"); //First parameter is Your encrypted text, the second is key you want to use for decryption it.
+    ```
+
+## Example programs
+
+Uhm... There aren't any examples (for now)... I will maybe create some... Later...

build.sh

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+#!/bin/sh
+
+make
+
+if [ "$1" == "debug" ]; then
+    ./out/why2
+fi

include/decrypter.h

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+#ifndef WHY2_DECRYPTER_H
+#define WHY2_DECRYPTER_H
+
+char *decryptText(char *text, char *key); //TEXT from WILL BE DECRYPTED WITH KEY AND RETURNED
+
+#endif

include/encrypter.h

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+#ifndef WHY2_ENCRYPTER_H
+#define WHY2_ENCRYPTER_H
+
+char *encryptText(char *text, char *keyNew); //TEXT from WILL BE ENCRYPTED WITH RANDOM PASSWORD [KEY] (WHICH WILL BE PRINTED OUT) AND RETURNED
+
+#endif

include/flags.h

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+#ifndef WHY2_FLAGS_H
+#define WHY2_FLAGS_H
+
+#define KEY_LENGTH 50
+#define ENCRYPTION_SEPARATOR '.'
+#define ENCRYPTION_SEPARATOR_STRING "."
+
+#define INVALID_KEY 1
+
+#endif

src/decrypter.c

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+#include "../include/decrypter.h"
+
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+
+#include "../include/flags.h"
+
+char*
+decryptText(char *text, char *key)
+{
+    //CHECK FOR INVALID key
+    if (strlen(key) != KEY_LENGTH)
+    {
+        fprintf(stderr, "Key must be 50 characters long!\n");
+        exit(INVALID_KEY);
+    }
+    
+    //VARIABLES
+    char *returningText;
+    int numberBuffer;
+    char *textBuffer;
+
+    numberBuffer = 1;
+
+    //GET LENGHT OF returningText AND textKeyChain
+    for (int i = 0; i < strlen(text); i++)
+    {
+        if (text[i] == ENCRYPTION_SEPARATOR) numberBuffer++;
+    }
+
+    //SET LENGTH
+    returningText = malloc(numberBuffer);
+    int textKeyChain[numberBuffer];
+    int encryptedTextKeyChain[numberBuffer];
+
+    //LOAD textKeyChain
+    for (int i = 0; i < (sizeof(textKeyChain) / sizeof(int)); i++)
+    {
+        numberBuffer = i;
+
+        //CHECK, IF numberBuffer ISN'T GREATER THAN KEY_LENGTH AND CUT UNUSED LENGTH
+        while (numberBuffer >= KEY_LENGTH)
+        {
+            numberBuffer -= KEY_LENGTH;
+        }
+
+        //FILL textKeyChain
+        if ((numberBuffer + 1) % 3 == 0)
+        {
+            textKeyChain[i] = key[numberBuffer] * key[numberBuffer + 1];
+        } else if ((numberBuffer + 1) % 2 == 0)
+        {
+            textKeyChain[i] = key[numberBuffer] - key[numberBuffer + 1];
+        } else
+        {
+            textKeyChain[i] = key[numberBuffer] + key[numberBuffer + 1];
+        }
+    }
+
+    //LOAD encryptedTextKeyChain
+    for (int i = 0; i < (sizeof(encryptedTextKeyChain) / sizeof(int)); i++)
+    {
+        numberBuffer = 0;
+
+        //GET LENGTH OF EACH CHARACTER
+        for (int j = 0; j < strlen(text); j++)
+        {
+            if (text[j] == ENCRYPTION_SEPARATOR) break;
+
+            numberBuffer++;
+        }
+
+        textBuffer = malloc(numberBuffer);
+
+        //LOAD textBuffer
+        for (int j = 0; j < strlen(text); j++)
+        {
+            textBuffer[j] = text[j];
+
+            if (numberBuffer == j) break;
+        }
+
+        encryptedTextKeyChain[i] = atoi(textBuffer);
+
+        text += numberBuffer + 1;
+        free(textBuffer);
+    }
+
+    //DECRYPT TEXT
+    for (int i = 0; i < (sizeof(textKeyChain) / sizeof(int)); i++)
+    {
+        textKeyChain[i] -= encryptedTextKeyChain[i];
+    }
+
+    //LOAD returningText
+    for (int i = 0; i < sizeof(textKeyChain) / sizeof(int); i++)
+    {
+        returningText[i] = (char) textKeyChain[i];
+    }
+
+    return returningText;
+}

src/encrypter.c

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+#include "../include/encrypter.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include <math.h>
+
+#include "../include/flags.h"
+
+char*
+encryptText(char *text, char *keyNew)
+{
+    srand(time(0)); //TRY TO MAKE RANDOM GENERATION REALLY "RANDOM"
+
+    //VARIABLES
+    char *key = malloc(KEY_LENGTH);
+    char *returningText;
+    char *textBuffer;
+    int textKeyChain[strlen(text)];
+    int numberBuffer;
+
+    if (keyNew != NULL)
+    {
+        if (strlen(keyNew) != KEY_LENGTH)
+        {
+            fprintf(stderr, "Key must be 50 characters long!\n");
+            exit(INVALID_KEY);
+        }
+
+        strcpy(key, keyNew);
+
+        goto skipKey;
+    }
+
+    //LOAD KEY
+    for (int i = 0; i < KEY_LENGTH; i++)
+    {
+        //SET numberBuffer TO RANDOM NUMBER BETWEEN 0 AND 52
+        numberBuffer = (rand() % 52) + 1;
+        
+        //GET CHAR FROM numberBuffer
+        if (numberBuffer > 26)
+        {
+            numberBuffer += 70;
+        } else
+        {
+            numberBuffer += 64;
+        }
+
+        key[i] = (char) numberBuffer;
+    }
+
+    printf("Your key is: %s\n!!! SAVE IT SOMEWHERE !!!\n\n", key);
+
+    skipKey:
+
+    //LOAD textKeyChain
+    for (int i = 0; i < (sizeof(textKeyChain) / sizeof(int)); i++)
+    {
+        numberBuffer = i;
+
+        //CHECK, IF numberBuffer ISN'T GREATER THAN KEY_LENGTH AND CUT UNUSED LENGTH
+        while (numberBuffer >= KEY_LENGTH)
+        {
+            numberBuffer -= KEY_LENGTH;
+        }
+
+        //FILL textKeyChain
+        if ((numberBuffer + 1) % 3 == 0)
+        {
+            textKeyChain[i] = key[numberBuffer] * key[numberBuffer + 1];
+        } else if ((numberBuffer + 1) % 2 == 0)
+        {
+            textKeyChain[i] = key[numberBuffer] - key[numberBuffer + 1];
+        } else
+        {
+            textKeyChain[i] = key[numberBuffer] + key[numberBuffer + 1];
+        }
+    }
+
+    //ACTUALLY ENCRYPT TEXT
+    for (int i = 0; i < strlen(text); i++)
+    {
+        textKeyChain[i] -= (int) text[i];
+    }
+
+    numberBuffer = 0;
+
+    //COUNT REQUIRED SIZE FOR returningText
+    for (int i = 0; i < (sizeof(textKeyChain) / sizeof(int)); i++)
+    {
+        numberBuffer += floor(log10(abs(textKeyChain[i]))) + 1;
+
+        //CHECK FOR MINUS
+        if (textKeyChain[i] > 0) numberBuffer++;
+    }
+
+    //ALLOCATE returningText (WITH THE SEPARATORS)
+    returningText = malloc(numberBuffer + (sizeof(textKeyChain) / sizeof(int) - 1));
+
+    //LOAD returningText
+    for (int i = 0; i < (sizeof(textKeyChain) / sizeof(int)); i++)
+    {
+        textBuffer = malloc(floor(log10(abs(textKeyChain[i]))));
+
+        sprintf(textBuffer, "%d", textKeyChain[i]);
+
+        strcat(returningText, textBuffer);
+
+        if (i != (sizeof(textKeyChain) / sizeof(int) - 1))
+        {
+            strcat(returningText, ENCRYPTION_SEPARATOR_STRING);
+        }
+
+        free(textBuffer);
+    }
+
+    //DEALLOCATION
+    free(key);
+    
+    return returningText;
+}

src/test/main.c

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+#include <stdio.h>
+#include <stdlib.h>
+
+#include "../../include/encrypter.h"
+#include "../../include/decrypter.h"
+
+int
+main(int args, char *argv[])
+{
+    char *text = encryptText("Pepa smrdí.", "dsadhagsdhuhasvbdzgavdgasvgzduasvgzdavdhbashudbuas");
+    printf("%s\n", text);
+
+    text = decryptText(text, "dsadhagsdhuhasvbdzgavdgasvgzduasvgzdavdhbashudbuas");
+    printf("%s\n", text);
+
+	free(text);
+    return 0;
+}