# This script installs the PyCryptoDome library for ECC encryption and decryption using the ECDH algorithm.

# The following command uses pip to install the pycryptodome-ecdh package.
# pip is a package management system used to install and manage software packages written in Python.
# The install command is used to install a package, and the package name is specified after the "install" keyword.
# In this case, the package name is "pycryptodome-ecdh".
# The "-ecdh" suffix indicates that this package specifically supports the ECDH algorithm.
# The "pip install" command must be run in a terminal or command prompt.

# To use this script, simply run it in a terminal or command prompt.
# The script will automatically install the PyCryptoDome library for ECC encryption and decryption.

# The "pip install" command may require administrative privileges to run.
# If you encounter an error, try running the script as an administrator or using the "sudo" command before the "pip install" command.

# The PyCryptoDome library is a fork of the PyCrypto library, which provides cryptographic functions for Python.
# The PyCryptoDome library is a more actively maintained and updated version of PyCrypto.
# It is used for ECC encryption and decryption, which is a type of public-key cryptography that uses elliptic curves.
# ECC is known for its efficiency and requires less memory, making it perfect for use in resource-constrained environments like IoT devices or mobile phones.

# The "pip install" command will download and install the pycryptodome-ecdh package from the Python Package Index (PyPI).
# PyPI is a repository of software packages for the Python programming language.
# The pycryptodome-ecdh package is specifically designed for use with the PyCryptoDome library and the ECDH algorithm.

# Once the installation is complete, the PyCryptoDome library will be available for use in your Python scripts.
# You can import the library using the "import" keyword, followed by the name of the library.
# For example, to use the ECC functions in your script, you would use the following import statement:
# import pycryptodome
# This will allow you to access all the functions and classes within the PyCryptoDome library.

# Congratulations, you have successfully installed the PyCryptoDome library for ECC encryption and decryption!
# You can now use this powerful library to secure your data and communications.

# Import necessary modules from the cryptography library
from cryptography.hazmat.primitives import serialization
from cryptography.hazmat.primitives.asymmetric import ec
from cryptography.hazmat.primitives.serialization import PrivateFormat, PublicFormat

# Generate a new ECC key pair using the P-256 curve
# Create a new ECC private key using the SECP256R1 curve
key = ec.generate_private_key(ec.SECP256R1())

# Get the public key from the private key
public_key = key.public_key()

# Serialize the public key in PEM format
public_bytes = public_key.public_bytes(Encoding.PEM, PublicFormat.SubjectPublicKeyInfo)

# Serialize the private key in DER format
private_bytes = key.private_bytes(Encoding.DER, PrivateFormat.PKCS8, None)

# The private key can be loaded from the serialized bytes using the load_pem_private_key function
# The private key is loaded in the TraditionalOpenSSL format
private_key = serialization.load_pem_private_key(private_bytes, password=None, format=serialization.PrivateFormat.TraditionalOpenSSL)

# Import necessary modules
from cryptography.hazmat.primitives import serialization
from cryptography.hazmat.primitives.asymmetric import ec
from cryptography.hazmat.primitives.serialization import PrivateFormat, PublicFormat

# Load the public key from a PEM file
with open('public_key.pem', 'rb') as f:
    public_bytes = f.read() # Read the contents of the public key file and store it in a variable

# Convert the bytes to an object that can be used for encryption
public_key = serialization.load_pem_public_key(public_bytes, backend=default_backend()) # Convert the public key bytes into an object that can be used for encryption

# Encrypt some sensitive data using ECC encryption and save it to a file
with open('encrypted_data', 'wb') as f:
    encrypter = ec.ECDHEncrypter(public_key) # Create an encrypter object using the public key
    message = b'YOUR SECRET DATA HERE' # Define the sensitive data to be encrypted
    ciphertext, tag = encrypter.update_and_finalize(message) # Encrypt the data and generate a tag for authentication
    f.write(ciphertext + tag) # Write the encrypted data and tag to a file

# Import necessary modules
from cryptography.hazmat.primitives import serialization
from cryptography.hazmat.primitives.asymmetric import ec
from cryptography.hazmat.primitives.serialization import PrivateFormat, PublicFormat

# Load the private key from a PEM file
with open('private_key.pem', 'rb') as f:
    private_bytes = f.read()

# Convert the bytes to an object that can be used for decryption
private_key = serialization.load_pem_private_key(private_bytes, backend=default_backend())

# Load the encrypted data from a file and decrypt it using ECC encryption
with open('encrypted_data', 'rb') as f:
    # Read the ciphertext and tag from the file
    ciphertext, tag = f.read()
    # Create an ECDHDecrypter object using the private key
    decrypter = ec.ECDHDecrypter(private_key)
    # Update and finalize the decryption process using the ciphertext and tag
    message, _ = decrypter.update_and_finalize(ciphertext + tag)

# The decrypted message can now be accessed and used as needed