added file encryption and decryption tutorial

Author: x4nth055

Diff for: README.md

@@ -16,6 +16,7 @@ This is a repository of all the tutorials of [The Python Code](https://www.thepy
     - [Writing a Keylogger in Python from Scratch](https://www.thepythoncode.com/article/write-a-keylogger-python). ([code](ethical-hacking/keylogger))
     - [Making a Port Scanner using sockets in Python](https://www.thepythoncode.com/article/make-port-scanner-python). ([code](ethical-hacking/port_scanner))
     - [How to Create a Reverse Shell in Python](https://www.thepythoncode.com/article/create-reverse-shell-python). ([code](ethical-hacking/reverse_shell))
+    - [How to Encrypt and Decrypt Files in Python](https://www.thepythoncode.com/article/encrypt-decrypt-files-symmetric-python). ([code](ethical-hacking/file-encryption))
 
 - ### [Machine Learning](https://www.thepythoncode.com/topic/machine-learning)
     - ### [Natural Language Processing](https://www.thepythoncode.com/topic/nlp)

Diff for: ethical-hacking/file-encryption/README.md

@@ -0,0 +1,36 @@
+# [How to Encrypt and Decrypt Files in Python](https://www.thepythoncode.com/article/encrypt-decrypt-files-symmetric-python)
+To run this:
+- `pip3 install -r requirements.txt`
+- 
+    ```
+    python crypt --help
+    ```
+    **Output:**
+    ```
+    usage: crypt.py [-h] [-g] [-e] [-d] file
+
+    Simple File Encryptor Script
+
+    positional arguments:
+    file                File to encrypt/decrypt
+
+    optional arguments:
+    -h, --help          show this help message and exit
+    -g, --generate-key  Whether to generate a new key or use existing
+    -e, --encrypt       Whether to encrypt the file, only -e or -d can be
+                        specified.
+    -d, --decrypt       Whether to decrypt the file, only -e or -d can be
+                        specified.
+    ```
+- If you want to encrypt `data.csv` using a new generated key:
+    ```
+    python crypt.py data.csv --generate-key --encrypt
+    ```
+- To decrypt it (must be same key, using `--generate-key` flag with decrypt won't be able to get the original file):
+    ```
+    python crypt.py data.csv --decrypt
+    ```
+- To encrypt another file using the same key generated previously:
+    ```
+    python crypt.py another_file --encrypt
+    ```

Diff for: ethical-hacking/file-encryption/crypt.py

@@ -0,0 +1,86 @@
+from cryptography.fernet import Fernet
+import os
+
+
+def write_key():
+    """
+    Generates a key and save it into a file
+    """
+    key = Fernet.generate_key()
+    with open("key.key", "wb") as key_file:
+        key_file.write(key)
+
+def load_key():
+    """
+    Loads the key from the current directory named `key.key`
+    """
+    return open("key.key", "rb").read()
+
+
+def encrypt(filename, key):
+    """
+    Given a filename (str) and key (bytes), it encrypts the file and write it
+    """
+    f = Fernet(key)
+    with open(filename, "rb") as file:
+        # read all file data
+        file_data = file.read()
+    # encrypt data
+    encrypted_data = f.encrypt(file_data)
+    # write the encrypted file
+    with open(filename, "wb") as file:
+        file.write(encrypted_data)
+
+
+def decrypt(filename, key):
+    """
+    Given a filename (str) and key (bytes), it decrypts the file and write it
+    """
+    f = Fernet(key)
+    with open(filename, "rb") as file:
+        # read the encrypted data
+        encrypted_data = file.read()
+    # decrypt data
+    decrypted_data = f.decrypt(encrypted_data)
+    # write the original file
+    with open(filename, "wb") as file:
+        file.write(decrypted_data)
+
+
+if __name__ == "__main__":
+    import argparse
+    parser = argparse.ArgumentParser(description="Simple File Encryptor Script")
+    parser.add_argument("file", help="File to encrypt/decrypt")
+    parser.add_argument("-g", "--generate-key", dest="generate_key", action="store_true",
+                        help="Whether to generate a new key or use existing")
+    parser.add_argument("-e", "--encrypt", action="store_true",
+                        help="Whether to encrypt the file, only -e or -d can be specified.")
+    parser.add_argument("-d", "--decrypt", action="store_true",
+                        help="Whether to decrypt the file, only -e or -d can be specified.")
+
+    args = parser.parse_args()
+    file = args.file
+    generate_key = args.generate_key
+
+    if generate_key:
+        write_key()
+    # load the key
+    key = load_key()
+
+    encrypt_ = args.encrypt
+    decrypt_ = args.decrypt
+
+    if encrypt_ and decrypt_:
+        raise TypeError("Please specify whether you want to encrypt the file or decrypt it.")
+    elif encrypt_:
+        encrypt(file, key)
+    elif decrypt_:
+        decrypt(file, key)
+    else:
+        raise TypeError("Please specify whether you want to encrypt the file or decrypt it.")
+
+    
+
+    
+
+