3DES in Python

Triple DES is a symmetric encryption algorithm that applies the Data Encryption Standard (DES) algorithm three times to enhance security. The code generates a 24-byte key, an initialization vector (IV), and utilizes the Cipher Feedback (CFB) mode. It showcases the process of encrypting a given data block, padding it to match the block size, and then decrypting it, ensuring secure data transmission.

3DES Encryption

The pycryptodome library facilitates these cryptographic operations, emphasizing the importance of using appropriate key sizes and initialization vectors for robust encryption practices.If you don't have the pycryptodome library installed, you can install it using:

pip install pycryptodome
Full Source | Python
from Crypto.Cipher import DES3 from Crypto.Random import get_random_bytes from Crypto.Util.Padding import pad, unpad # Step 1: Generate a 24-byte key for 3DES (Triple DES) key = b'ThisIs24BytesSecretKey' # Step 2: Generate an IV (Initialization Vector) for the cipher iv = get_random_bytes(8) # Step 3: Create a Triple DES cipher object cipher = DES3.new(key, DES3.MODE_CFB, iv=iv) # Step 4: Provide the data you want to encrypt data_to_encrypt = b'This is the data to be encrypted using 3DES.' # Step 5: Pad the data to match the block size of the cipher padded_data = pad(data_to_encrypt, DES3.block_size) # Step 6: Encrypt the padded data encrypted_data = cipher.encrypt(padded_data) # Step 7: Print the encrypted data print("Encrypted Data:", encrypted_data.hex()) # Step 8: Decrypt the encrypted data decrypted_data = cipher.decrypt(encrypted_data) # Step 9: Unpad the decrypted data unpadded_data = unpad(decrypted_data, DES3.block_size) # Step 10: Print the decrypted data print("Decrypted Data:", unpadded_data.decode('utf-8'))
Points to Remember
  1. Key length: 3DES uses a 24-byte key (three 8-byte DES keys).
  2. Encryption mode: ECB mode is simple but not recommended for secure applications. Consider other modes like CBC or CTR for better security.
  3. Padding: PKCS#5 padding is recommended for security.
  4. Security considerations: 3DES is considered outdated and less secure than modern algorithms like AES. However, it may still be used in legacy systems.


Triple DES (3DES) is a symmetric encryption algorithm that enhances the security of the Data Encryption Standard (DES) by applying the DES algorithm three times consecutively. It operates with a 24-byte key, consisting of three 8-byte subkeys, and involves processes like key generation, initialization vector usage, and padding to securely encrypt and decrypt data, providing a higher level of cryptographic strength compared to the original DES algorithm.