Add encryption class

src/encryptor.py

@@ -0,0 +1,57 @@
+import base64
+import os
+from Crypto.Cipher import AES
+from Crypto.Protocol.KDF import PBKDF2
+from Crypto.Random import get_random_bytes
+
+class Encryptor:
+    def __init__(self, password: str):
+        self.password = password.encode()
+        self.salt_size = 16
+        self.iv_size = 16
+        self.key_size = 32
+        self.iterations = 100_000
+
+    def _derive_key(self, salt: bytes) -> bytes:
+        """
+        Dérive une clé à partir du mot de passe et du sel.
+        """
+        return PBKDF2(self.password, salt, dkLen=self.key_size, count=self.iterations)
+
+    def encrypt(self, plaintext: str) -> str:
+        """
+        Encrypte une chaîne de texte en base64.
+        """
+        salt = get_random_bytes(self.salt_size)
+        key = self._derive_key(salt)
+        iv = get_random_bytes(self.iv_size)
+
+        # Padding (PKCS7)
+        pad_len = AES.block_size - (len(plaintext.encode()) % AES.block_size)
+        padded = plaintext + chr(pad_len) * pad_len
+
+        cipher = AES.new(key, AES.MODE_CBC, iv)
+        ciphertext = cipher.encrypt(padded.encode())
+
+        # Encodage final : salt + iv + ciphertext
+        encrypted_data = base64.b64encode(salt + iv + ciphertext).decode()
+        return encrypted_data
+
+    def decrypt(self, encrypted_text: str) -> str:
+        """
+        Décrypte une chaîne encodée en base64.
+        """
+        data = base64.b64decode(encrypted_text)
+        salt = data[:self.salt_size]
+        iv = data[self.salt_size:self.salt_size + self.iv_size]
+        ciphertext = data[self.salt_size + self.iv_size:]
+
+        key = self._derive_key(salt)
+        cipher = AES.new(key, AES.MODE_CBC, iv)
+        padded_plaintext = cipher.decrypt(ciphertext)
+
+        # Retrait du padding
+        pad_len = padded_plaintext[-1]
+        plaintext = padded_plaintext[:-pad_len].decode()
+
+        return plaintext