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How to encrypt a file in Python

How to encrypt a file in Python.

Here is a step-by-step tutorial on how to encrypt a file in Python:

Step 1: Import the necessary libraries​

First, we need to import the necessary libraries for encryption. In this tutorial, we will be using the cryptography library, which provides a suite of cryptographic recipes and algorithms.

from cryptography.fernet import Fernet

Step 2: Generate a key​

To encrypt and decrypt a file, we need a key. The key is used to perform the encryption and decryption operations. In this example, we will use the Fernet class from the cryptography library to generate a key.

key = Fernet.generate_key()

Step 3: Save the key​

Next, we need to save the key to a file so that we can use it for encryption and decryption later. You can choose a filename and location of your choice to save the key.

with open('key.txt', 'wb') as key_file:
    key_file.write(key)

Step 4: Load the key​

Before we can encrypt or decrypt a file, we need to load the key from the saved file. We will read the key from the file and store it in a variable.

with open('key.txt', 'rb') as key_file:
    key = key_file.read()

Step 5: Encrypt the file​

Now that we have the key, we can start encrypting a file. In this example, we will encrypt a text file, but you can encrypt any type of file using the same approach.

# Read the file content
with open('plaintext.txt', 'rb') as file:
    plaintext = file.read()

# Create a Fernet object with the key
fernet = Fernet(key)

# Encrypt the file content
encrypted = fernet.encrypt(plaintext)

# Save the encrypted content to a new file
with open('encrypted.txt', 'wb') as file:
    file.write(encrypted)

Step 6: Decrypt the file​

To decrypt the encrypted file, we will follow a similar process. First, we load the key from the saved file, then we read the encrypted content from the file and decrypt it using the key.

# Load the key from the file
with open('key.txt', 'rb') as key_file:
    key = key_file.read()

# Read the encrypted content
with open('encrypted.txt', 'rb') as file:
    encrypted = file.read()

# Create a Fernet object with the key
fernet = Fernet(key)

# Decrypt the encrypted content
decrypted = fernet.decrypt(encrypted)

# Save the decrypted content to a new file
with open('decrypted.txt', 'wb') as file:
    file.write(decrypted)

And that's it! You have successfully encrypted and decrypted a file using Python. Remember to replace the filenames and paths in the code with your own file names and paths.