small refactor in libs + fully functional hybrid encryption 🗣️ ‼️ 🔥

delivery1/cryptLib/decryptionFuncts.py

@@ -1,26 +0,0 @@
-import sys
-
-from cryptography.hazmat.primitives import serialization, hashes
-from cryptography.hazmat.primitives.asymmetric import rsa, padding
-
-
-def decryptFile(private_key, cipher_text):
-	plain_text = private_key.decrypt(
-		cipher_text,
-		padding.OAEP(
-			mgf=padding.MGF1(algorithm=hashes.SHA256()),
-			algorithm=hashes.SHA256(),
-			label=None
-		)
-	)
-	return plain_text
-
-
-def load_private_key(file, paswd=None):
-	with open(file, 'rb') as key_file:
-		private_key = serialization.load_pem_private_key(
-			key_file.read(),
-			password=paswd,
-		)
-
-	return private_key

delivery1/cryptLib/encryptionFuncts.py

@@ -1,23 +0,0 @@
-import sys
-
-from cryptography.hazmat.primitives import serialization, hashes
-from cryptography.hazmat.primitives.asymmetric import rsa, padding
-
-def encryptFile(public_key, text):
-	ciphertext = public_key.encrypt(
-		text,
-		padding.OAEP(
-			mgf=padding.MGF1(algorithm=hashes.SHA256()),
-			algorithm=hashes.SHA256(),
-			label=None
-		)
-	)
-	return ciphertext
-
-def load_public_key(file):
-	with open(file, 'rb') as key_file:
-		public_key = serialization.load_pem_public_key(
-			key_file.read(),
-		)
-
-	return public_key

delivery1/lib/decryption_functs.py

@@ -0,0 +1,69 @@
+import sys
+
+from cryptography.hazmat.primitives import serialization, hashes
+from cryptography.hazmat.primitives.asymmetric import padding
+from cryptography.hazmat.primitives.ciphers import Cipher, algorithms, modes
+from cryptography.hazmat.backends import default_backend
+
+
+
+# function to decrypt data using a symmetric key
+def decrypt_symmetric(key, ciphertext):
+	# generate a random IV
+	iv = ciphertext[:16]
+
+	# decipher the data using AES in CFB mode
+	ciphertext = ciphertext[16:]
+	cipher = Cipher(algorithms.AES(key), modes.CFB(iv), backend=default_backend())
+	decryptor = cipher.decryptor()
+
+	return decryptor.update(ciphertext) + decryptor.finalize()
+
+
+# function that calls and combines the symmetric and asymmetric decryption
+def decrypt_hybrid(private_key, encrypted_data):
+	# extract the encrypted symmetric key and the encrypted data (remember that the data is symmetric + asymmetric)
+	encrypted_symmetric_key = encrypted_data[:private_key.key_size // 8]
+	encrypted_data = encrypted_data[private_key.key_size // 8:]
+
+	# decrypt the symmetric key using the RSA private key
+	symmetric_key = private_key.decrypt(
+		encrypted_symmetric_key,
+		padding.OAEP(
+			mgf=padding.MGF1(algorithm=hashes.SHA256()),
+			algorithm=hashes.SHA256(),
+			label=None
+		)
+	)
+
+	# decrypt the data using the decrypted symmetric key
+	return decrypt_symmetric(symmetric_key, encrypted_data)
+
+
+# main function to decrypt the file
+def decrypt_file(private_key, encrypted_file, decrypted_file):
+	with open(encrypted_file, 'rb') as f:
+		encrypted_content = f.read()
+
+	decrypted_content = decrypt_hybrid(private_key, encrypted_content)
+
+	with open(decrypted_file, 'wb') as f:
+		f.write(decrypted_content)
+
+
+# function to load a private key from a file
+def load_private_key(file, passwd=None):
+	if passwd is not None:
+		passwd = passwd.encode('utf-8')
+
+	try:
+		with open(file, 'rb') as key_file:
+			private_key = serialization.load_pem_private_key(
+				key_file.read(),
+				password=passwd,
+			)
+	except ValueError as e:
+		raise ValueError("Error: The password is not valid.") from e
+
+
+	return private_key

delivery1/lib/digest.py

@@ -0,0 +1,7 @@
+import cryptography.hazmat.primitives.hashes
+
+
+def get_hash(data):
+	digest = cryptography.hazmat.primitives.hashes.Hash(cryptography.hazmat.primitives.hashes.SHA256())
+	digest.update(data)
+	return digest.finalize()

delivery1/lib/encryption_functs.py

@@ -0,0 +1,67 @@
+import sys, os
+
+from cryptography.hazmat.primitives import serialization, hashes
+from cryptography.hazmat.primitives.asymmetric import rsa, padding
+from cryptography.hazmat.primitives.kdf.pbkdf2 import PBKDF2HMAC
+from cryptography.hazmat.primitives.ciphers import Cipher, algorithms, modes
+from cryptography.hazmat.backends import default_backend
+
+
+# function to generate a 256-bit symmetric key
+def generate_symmetric_key():
+	return os.urandom(32)
+
+
+# function to encrypt data using a symmetric key
+def encrypt_symmetric(key, plain_text):
+	# generate a random IV
+	iv = os.urandom(16)
+
+	# cipher the data using AES in CFB mode
+	cipher = Cipher(algorithms.AES(key), modes.CFB(iv), backend=default_backend())
+	encryptor = cipher.encryptor()
+	ciphertext = encryptor.update(plain_text) + encryptor.finalize()
+
+	return iv + ciphertext
+
+
+# function that calls and combines the symmetric and asymmetric encryption
+def encrypt_hybrid(public_key, plaintext):
+	# generate a random symmetric key
+	symmetric_key = generate_symmetric_key()
+
+	encrypted_data = encrypt_symmetric(symmetric_key, plaintext)
+
+	# encrypt the symmetric key with the public key
+	encrypted_symmetric_key = public_key.encrypt(
+		symmetric_key,
+		padding.OAEP(
+			mgf=padding.MGF1(algorithm=hashes.SHA256()),
+			algorithm=hashes.SHA256(),
+			label=None
+		)
+	)
+
+	# combine the symmetric key and the encrypted data
+	return encrypted_symmetric_key + encrypted_data
+
+
+# main function to encrypt the file
+def encrypt_file(public_key, original_file, encrypted_file):
+	with open(original_file, 'rb') as f:
+		plaintext = f.read()
+
+	encrypted_content = encrypt_hybrid(public_key, plaintext)
+
+	with open(encrypted_file, 'wb') as f:
+		f.write(encrypted_content)
+
+
+# function to load a public key from a file
+def load_public_key(file):
+	with open(file, 'rb') as key_file:
+		public_key = serialization.load_pem_public_key(
+			key_file.read(),
+		)
+
+	return public_key

delivery1/lib/key_pair.py

@@ -4,8 +4,7 @@ from cryptography.hazmat.primitives import serialization, hashes
 from cryptography.hazmat.primitives.asymmetric import rsa, padding
 
 
-def generate_key_pair(passwd=None):
+def generate_key_pair(pub_name, priv_name, key_size, passwd=None):
-	pub_name, priv_name, key_size = sys.argv[1:]
 
 	private_key = rsa.generate_private_key(
 		public_exponent=65537,
@@ -33,6 +32,3 @@ def generate_key_pair(passwd=None):
 				format=serialization.PrivateFormat.TraditionalOpenSSL,
 				encryption_algorithm=serialization.BestAvailableEncryption(passwd.encode())
 			))
-
-	return pub_name, priv_name
-

delivery1/lib/tests/test_digest.py

@@ -0,0 +1,36 @@
+import os
+
+from digest import *
+
+def test_equal_string():
+	string_one = "Hello, World!"
+	string_two = "Hello, World!"
+
+	assert get_hash(bytes(string_one, 'utf-8')) == get_hash(bytes(string_two, 'utf-8'))
+
+
+def test_diff_string():
+	string_one = "Hello, World!"
+	string_two = "Hello, World"
+
+	assert get_hash(bytes(string_one, 'utf-8')) != get_hash(bytes(string_two, 'utf-8'))
+
+
+def test_equal_file():
+	# create equal files
+	os.system("dd if=/dev/zero of=test.txt bs=1024 count=1000  >/dev/null 2>&1")
+	os.system("dd if=/dev/zero of=test2.txt bs=1024 count=1000  >/dev/null 2>&1")
+
+	assert get_hash(open("test.txt", "rb").read()) == get_hash(open("test2.txt", "rb").read())
+	os.remove("test.txt")
+	os.remove("test2.txt")
+
+
+def test_diff_file():
+	# create different files
+	os.system("dd if=/dev/urandom of=test.txt bs=1024 count=1000  >/dev/null 2>&1")
+	os.system("dd if=/dev/urandom of=test2.txt bs=1024 count=1000  >/dev/null 2>&1")
+
+	assert get_hash(open("test.txt", "rb").read()) != get_hash(open("test2.txt", "rb").read())
+	os.remove("test.txt")
+	os.remove("test2.txt")

delivery1/lib/tests/test_encryption.py

@@ -0,0 +1,187 @@
+import os
+
+from decryption_functs import *
+from encryption_functs import *
+from key_pair import *
+
+def test_encryption_no_pwd():
+	# create a file to encrypt
+	with open("test.txt", "w") as f:
+		f.write("Hello, World!")
+
+	# generate a key pair
+	generate_key_pair('public.pem', 'private.pem', '2048')
+
+	# load the public and private keys
+	public_key = load_public_key("public.pem")
+	private_key = load_private_key("private.pem")
+
+	# encrypt the file
+	encrypt_file(public_key, "test.txt", "test.enc")
+
+	# decrypt the file
+	decrypt_file(private_key, "test.enc", "test.dec")
+
+	# check that the decrypted file is the same as the original
+	with open("test.dec", "r") as f:
+		assert f.read() == "Hello, World!"
+
+	# cleanup
+	os.remove("test.txt")
+	os.remove("test.enc")
+	os.remove("test.dec")
+	os.remove("public.pem")
+	os.remove("private.pem")
+
+
+def test_encryption_with_pwd():
+	# create a file to encrypt
+	with open("test.txt", "w") as f:
+		f.write("Hello, World!")
+
+	# generate a key pair
+	generate_key_pair('public.pem', 'private.pem', '2048', 'password')
+
+	# load the public and private keys
+	public_key = load_public_key("public.pem")
+	private_key = load_private_key("private.pem", 'password')
+
+	# encrypt the file
+	encrypt_file(public_key, "test.txt", "test.enc")
+
+	# decrypt the file
+	decrypt_file(private_key, "test.enc", "test.dec")
+
+	# check that the decrypted file is the same as the original
+	with open("test.dec", "r") as f:
+		assert f.read() == "Hello, World!"
+
+	# remove the files
+	os.remove("test.txt")
+	os.remove("test.enc")
+	os.remove("test.dec")
+	os.remove("public.pem")
+	os.remove("private.pem")
+
+
+def test_load_private_key_wrong_pwd():
+	# generate a key pair
+	generate_key_pair('public.pem', 'private.pem', '2048', 'password')
+
+	# try to load the private key with the wrong password
+	try:
+		load_private_key("private.pem", 'wrong_password')
+	except ValueError as e:
+		assert str(e) == "Error: The password is not valid."
+
+
+def test_1mb_file_with_pwd():
+	# create a 1mb file to encrypt
+	os.system("dd if=/dev/urandom of=test.txt bs=1024 count=1000  >/dev/null 2>&1")
+
+	# generate a key pair
+	generate_key_pair('public.pem', 'private.pem', '2048', 'password')
+
+	# load the public and private keys
+	public_key = load_public_key("public.pem")
+	private_key = load_private_key("private.pem", 'password')
+
+	# encrypt the file
+	encrypt_file(public_key, "test.txt", "test.enc")
+
+	# decrypt the file
+	decrypt_file(private_key, "test.enc", "test.dec")
+
+	# check that the decrypted file is the same as the original
+	assert open("test.txt", "rb").read() == open("test.dec", "rb").read()
+
+	# remove the files
+	os.remove("test.txt")
+	os.remove("test.enc")
+	os.remove("test.dec")
+	os.remove("public.pem")
+	os.remove("private.pem")
+
+
+def test_1mb_file_no_pwd():
+	# create a 1mb file to encrypt
+	os.system("dd if=/dev/urandom of=test.txt bs=1024 count=1000  >/dev/null 2>&1")
+
+	# generate a key pair
+	generate_key_pair('public.pem', 'private.pem', '2048')
+
+	# load the public and private keys
+	public_key = load_public_key("public.pem")
+	private_key = load_private_key("private.pem")
+
+	# encrypt the file
+	encrypt_file(public_key, "test.txt", "test.enc")
+
+	# decrypt the file
+	decrypt_file(private_key, "test.enc", "test.dec")
+
+	# check that the decrypted file is the same as the original
+	assert open("test.txt", "rb").read() == open("test.dec", "rb").read()
+
+	# remove the files
+	os.remove("test.txt")
+	os.remove("test.enc")
+	os.remove("test.dec")
+	os.remove("public.pem")
+	os.remove("private.pem")
+
+
+def test_100mb_file_with_pwd():
+	# create a 100mb file to encrypt
+	os.system("dd if=/dev/urandom of=test.txt bs=1024 count=100000  >/dev/null 2>&1")
+
+	# generate a key pair
+	generate_key_pair('public.pem', 'private.pem', '2048', 'password')
+
+	# load the public and private keys
+	public_key = load_public_key("public.pem")
+	private_key = load_private_key("private.pem", 'password')
+
+	# encrypt the file
+	encrypt_file(public_key, "test.txt", "test.enc")
+
+	# decrypt the file
+	decrypt_file(private_key, "test.enc", "test.dec")
+
+	# check that the decrypted file is the same as the original
+	assert open("test.txt", "rb").read() == open("test.dec", "rb").read()
+
+	# remove the files
+	os.remove("test.txt")
+	os.remove("test.enc")
+	os.remove("test.dec")
+	os.remove("public.pem")
+	os.remove("private.pem")
+
+
+def test_100mb_file_no_pwd():
+	# create a 100mb file to encrypt
+	os.system("dd if=/dev/urandom of=test.txt bs=1024 count=100000  >/dev/null 2>&1")
+
+	# generate a key pair
+	generate_key_pair('public.pem', 'private.pem', '2048')
+
+	# load the public and private keys
+	public_key = load_public_key("public.pem")
+	private_key = load_private_key("private.pem")
+
+	# encrypt the file
+	encrypt_file(public_key, "test.txt", "test.enc")
+
+	# decrypt the file
+	decrypt_file(private_key, "test.enc", "test.dec")
+
+	# check that the decrypted file is the same as the original
+	assert open("test.txt", "rb").read() == open("test.dec", "rb").read()
+
+	# remove the files
+	os.remove("test.txt")
+	os.remove("test.enc")
+	os.remove("test.dec")
+	os.remove("public.pem")
+	os.remove("private.pem")