From b523a7574d015066628ba3f906b7c323bcbc4762 Mon Sep 17 00:00:00 2001
From: StNicolay <103897650+StNicolay@users.noreply.github.com>
Date: Mon, 26 Sep 2022 21:15:43 +0300
Subject: [PATCH] Created functions to encrypt and decrypt account info

---
 src/cryptography/other_accounts.py | 43 ++++++++++++++++++++++++++++++
 1 file changed, 43 insertions(+)
 create mode 100644 src/cryptography/other_accounts.py

diff --git a/src/cryptography/other_accounts.py b/src/cryptography/other_accounts.py
new file mode 100644
index 0000000..f89e12d
--- /dev/null
+++ b/src/cryptography/other_accounts.py
@@ -0,0 +1,43 @@
+import base64
+
+import bcrypt
+
+from cryptography.hazmat.backends import default_backend
+from cryptography.hazmat.primitives import hashes
+from cryptography.hazmat.primitives.kdf.pbkdf2 import PBKDF2HMAC
+from cryptography.fernet import Fernet
+
+
+def generate_key(salt: bytes, master_pass_hash: bytes) -> bytes:
+    kdf = PBKDF2HMAC(
+        algorithm=hashes.SHA256(),
+        length=32,
+        salt=salt,
+        iterations=100000,
+        backend=default_backend(),
+    )
+    key = base64.urlsafe_b64encode(kdf.derive(master_pass_hash))
+    return key
+
+
+def encrypt_account_info(
+    login: str, passwd: str, master_pass_hash: bytes
+) -> tuple[bytes, bytes, bytes]:
+    """Encrypts login and password of a user using hash of their master password as a key.
+    Returns a tuple of encrypted login password and salt"""
+    salt = bcrypt.gensalt()
+    key = generate_key(salt, master_pass_hash)
+    f = Fernet(key)
+    enc_login = f.encrypt(login.encode("utf-8"))
+    enc_passwd = f.encrypt(passwd.encode("utf-8"))
+    return (enc_login, enc_passwd, salt)
+
+
+def decrypt_account_info(
+    enc_login: bytes, enc_pass: bytes, master_pass_hash: bytes, salt: bytes
+) -> tuple[str, str]:
+    key = generate_key(salt, master_pass_hash)
+    f = Fernet(key)
+    login_bytes = f.decrypt(enc_login)
+    pass_bytes = f.decrypt(enc_pass)
+    return (login_bytes.decode("utf-8"), pass_bytes.decode("utf-8"))