Examples
========

This page contains complete examples demonstrating common uses of DES PurePy.

Encrypting a Single Block
-------------------------

The following example encrypts a single 64-bit block using a hexadecimal key.

.. code-block:: python

   from des_PurePy import DES

   des = DES("0x133457799bbcdff1")

   ciphertext = des.encrypt("0x0123456789abcdef")

   print(ciphertext)

Output:

.. code-block:: text

   0x85e813540f0ab405fdf2e174492922f8

Decrypting Data
---------------

Decrypt the ciphertext using the same key.

.. code-block:: python

   from des_PurePy import DES

   des = DES("0x133457799bbcdff1")

   cleartext = des.decrypt("0x85e813540f0ab405fdf2e174492922f8")

   print(cleartext)

Output:

.. code-block:: text

   0x0123456789abcdef

Encrypting Text
---------------

The library accepts ``bytes`` objects, making it easy to encrypt text.

.. code-block:: python

   from des_PurePy import DES

   des = DES(b"password")

   ciphertext = des.encrypt(b"secret message")

   print(ciphertext)

Decrypting Text
---------------

After decrypting, convert the returned hexadecimal string back into bytes and decode it.

.. code-block:: python

   from des_PurePy import DES

   des = DES(b"password")

   ciphertext = des.encrypt(b"secret message")

   cleartext = des.decrypt(ciphertext)

   message = bytes.fromhex(cleartext[2:]).decode("utf-8")

   print(message)

Output:

.. code-block:: text

   secret message

Working with Binary Files
-------------------------

DES PurePy accepts ``bytes`` objects, so files can be encrypted by reading them as binary data.

.. code-block:: python

   from des_PurePy import DES

   des = DES(b"password")

   with open("input.bin", "rb") as infile:
       plaintext = infile.read()

   ciphertext = des.encrypt(plaintext)

   # Save the ciphertext
   with open("ciphertext.txt", "w", encoding="utf-8") as outfile:
       outfile.write(ciphertext)

   # Recover the original bytes
   recovered = bytes.fromhex(des.decrypt(ciphertext)[2:])

   with open("output.bin", "wb") as outfile:
       outfile.write(recovered)