Tutorial Python - Using AES Encryption [ Step by step ]

Learn about AES Encryption in Python, an essential approach to safeguarding sensitive data. This article provides practical examples and key insights, emphasizing its critical role in enhancing encryption protocols and preserving data confidentiality.

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What is AES?

AES is a widely utilized symmetric encryption algorithm renowned for its robust security and efficiency in safeguarding sensitive data. Adopted as a federal standard by the U.S. government, AES operates on fixed block sizes and employs symmetric key cryptography, where the same key is used for both encryption and decryption. Supporting key sizes of 128, 192, and 256 bits, AES serves as a standard encryption solution for various applications, ensuring secure data transmission, storage, and overall data integrity.

How does AES encryption work?

AES encryption works through a series of well-defined steps. The algorithm operates on fixed data block sizes and key lengths of 128, 192, or 256 bits. The encryption process involves several rounds of transformation, including substitution, permutation, and mixing operations. These rounds ensure that the input data is thoroughly scrambled, making it extremely difficult for unauthorized users to decipher the original information without the corresponding decryption key. AES is a symmetric encryption algorithm, which means the same key is used for both encryption and decryption. The strength of AES lies in its ability to securely protect sensitive information and resist various cryptographic attacks, making it a trusted and widely adopted standard for data encryption.

Why encrypt using AES in Python?

Encrypting using AES in Python offers a robust and reliable method for safeguarding sensitive data, ensuring confidentiality, integrity, and authenticity. By leveraging AES, Python developers can implement strong encryption protocols, making it significantly challenging for unauthorized entities to access and comprehend the encrypted information. Additionally, AES encryption is supported by various Python libraries, providing developers with a flexible and accessible means to integrate advanced security measures into their applications. This capability makes AES encryption in Python an essential practice for protecting data privacy and maintaining the integrity of sensitive information across various use cases, including secure communication, data storage, and transmission.

Tutorial Python – Using AES Encryption

Install the required Python package.

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Load the required Python libraries.

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Create a function to encrypt using AES 256.

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Create a Key and an Initial Vector.

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Ensure the key is 32 bytes long.

Ensure the Initial Vector is 16 bytes long.

The Initialization Vector is a random value used in conjunction with the encryption key for the AES algorithm. It is used to introduce randomness and prevent patterns in the plaintext from being observable in the ciphertext. The IV is essential for initializing the encryption process and enhancing the security of the encrypted data.

Encrypt a text using AES.

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Here is the command output.

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Create a function to decrypt using AES.

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Decrypt the cipher text using AES.

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Here is the command output.

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Here is the complete Python script.

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from cryptography.hazmat.primitives.ciphers import Cipher, algorithms, modes
from cryptography.hazmat.backends import default_backend
from cryptography.hazmat.primitives import padding

# Function to encrypt using AES in CBC mode
def encrypt_AES_CBC(data, key, iv):
    padder = padding.PKCS7(128).padder()  
    padded_data = padder.update(data.encode('utf-8'))  
    padded_data += padder.finalize()

cipher = Cipher(algorithms.AES(key), modes.CBC(iv), backend=default_backend())  
    encryptor = cipher.encryptor()  
    ciphertext = encryptor.update(padded_data) + encryptor.finalize()

return ciphertext

# Function to decrypt using AES in CBC mode
def decrypt_AES_CBC(ciphertext, key, iv):
    decryptor = Cipher(algorithms.AES(key), modes.CBC(iv), backend=default_backend()).decryptor()  
    decrypted_data = decryptor.update(ciphertext) + decryptor.finalize()

unpadder = padding.PKCS7(128).unpadder()  
    unpadded_data = unpadder.update(decrypted_data)  
    unpadded_data += unpadder.finalize()

return unpadded_data.decode('utf-8')

# Example usage
key = b'MySuperSecretKey2222222222222222'  # Encryption key (Ensure the key is 16, 24, or 32 bytes for AES-128, AES-192, or AES-256)
iv = b'MySuperSecretIV0'  # Initialization vector (Ensure the IV is 16 bytes)
plaintext = "This is my secret text"  
# Encrypt the plaintext
encrypted_text = encrypt_AES_CBC(plaintext, key, iv)  
print(f'Encrypted text: {encrypted_text}')

# Decrypt the encrypted text
decrypted_text = decrypt_AES_CBC(encrypted_text, key, iv)  
print(f'Decrypted text: {decrypted_text}')

Tutorial Python – Encrypt a file using AES

Encode a file using AES encryption.

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from cryptography.hazmat.primitives.ciphers import Cipher, algorithms, modes
from cryptography.hazmat.backends import default_backend
from cryptography.hazmat.primitives import padding

# Function to encrypt a file using AES in CBC mode
def encrypt_file_AES_CBC(input_file, output_encrypted_file, key, iv):
    with open(input_file, 'rb') as file:
        data = file.read()

padder = padding.PKCS7(128).padder()
    padded_data = padder.update(data) + padder.finalize()

cipher = Cipher(algorithms.AES(key), modes.CBC(iv), backend=default_backend())
    encryptor = cipher.encryptor()
    ciphertext = encryptor.update(padded_data) + encryptor.finalize()

with open(output_encrypted_file, 'wb') as file:
        file.write(ciphertext)

# Usage example
key = b'MySuperSecretKey2222222222222222'
iv = b'MySuperSecretIV0'
input_file = 'calc.exe'
output_encrypted_file = 'encrypted_output.txt'  # Output encrypted file

# Encrypt the input file
encrypt_file_AES_CBC(input_file, output_encrypted_file, key, iv)
print(f'File {input_file} encrypted and saved as {output_encrypted_file}.')

Decode a file using AES encryption.

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from cryptography.hazmat.primitives.ciphers import Cipher, algorithms, modes
from cryptography.hazmat.backends import default_backend
from cryptography.hazmat.primitives import padding

# Function to decrypt a binary file using AES in CBC mode
def decrypt_file_AES_CBC(input_encrypted_file, output_decrypted_file, key, iv):
    with open(input_encrypted_file, 'rb') as file:
        ciphertext = file.read()

decryptor = Cipher(algorithms.AES(key), modes.CBC(iv), backend=default_backend()).decryptor()
    decrypted_data = decryptor.update(ciphertext) + decryptor.finalize()

unpadder = padding.PKCS7(128).unpadder()
    unpadded_data = unpadder.update(decrypted_data) + unpadder.finalize()

with open(output_decrypted_file, 'wb') as file:
        file.write(unpadded_data)

# Usage example
key = b'MySuperSecretKey2222222222222222'
iv = b'MySuperSecretIV0'
output_encrypted_file = 'encrypted_output.txt'  # Output encrypted file
output_decrypted_file = 'mycalc.exe'

# Decrypt the encrypted file
decrypt_file_AES_CBC(output_encrypted_file, output_decrypted_file, key, iv)
print(f'File {output_encrypted_file} decrypted and saved as {output_decrypted_file}.')

Here is the complete Python script.

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from cryptography.hazmat.primitives.ciphers import Cipher, algorithms, modes
from cryptography.hazmat.backends import default_backend
from cryptography.hazmat.primitives import padding

# Function to encrypt a binary file using AES in CBC mode
def encrypt_file_AES_CBC(input_file, output_encrypted_file, key, iv):
    with open(input_file, 'rb') as file:
        data = file.read()

padder = padding.PKCS7(128).padder()
    padded_data = padder.update(data) + padder.finalize()

cipher = Cipher(algorithms.AES(key), modes.CBC(iv), backend=default_backend())
    encryptor = cipher.encryptor()
    ciphertext = encryptor.update(padded_data) + encryptor.finalize()

with open(output_encrypted_file, 'wb') as file:
        file.write(ciphertext)

# Function to decrypt a binary file using AES in CBC mode
def decrypt_file_AES_CBC(input_encrypted_file, output_decrypted_file, key, iv):
    with open(input_encrypted_file, 'rb') as file:
        ciphertext = file.read()

decryptor = Cipher(algorithms.AES(key), modes.CBC(iv), backend=default_backend()).decryptor()
    decrypted_data = decryptor.update(ciphertext) + decryptor.finalize()

unpadder = padding.PKCS7(128).unpadder()
    unpadded_data = unpadder.update(decrypted_data) + unpadder.finalize()

with open(output_decrypted_file, 'wb') as file:
        file.write(unpadded_data)

# Usage example
key = b'MySuperSecretKey2222222222222222'
iv = b'MySuperSecretIV0'
input_file = 'calc.exe'
output_encrypted_file = 'encrypted_output.txt'
output_decrypted_file = 'mycalc.exe'

# Encrypt the input file
encrypt_file_AES_CBC(input_file, output_encrypted_file, key, iv)
print(f'File {input_file} encrypted and saved as {output_encrypted_file}.')

# Decrypt the encrypted file
decrypt_file_AES_CBC(output_encrypted_file, output_decrypted_file, key, iv)
print(f'File {output_encrypted_file} decrypted and saved as {output_decrypted_file}.')

Conclusion

Implement AES encryption in Python to bolster data security. With its robust encryption algorithms and simple integration, AES is pivotal in safeguarding sensitive information. Safeguard your data with AES encryption in Python.

Python – Using AES Encryption

Python – Using AES Encryption

Equipment list

Related tutorial – Python

What is AES?

How does AES encryption work?

Why encrypt using AES in Python?

Tutorial Python – Using AES Encryption

Tutorial Python – Encrypt a file using AES

Conclusion

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