Added identity here

dragonion_core/proto/encryption/__init__.py

@@ -0,0 +1 @@
+pass

dragonion_core/proto/encryption/identity.py

@@ -0,0 +1,28 @@
+from attrs import define
+from cryptography.hazmat.primitives.asymmetric import rsa
+from cryptography.hazmat.primitives import serialization
+import base64
+
+
+@define
+class Identity:
+    """
+    Valid identity has fields
+    username - in most cases same as filename, represents identity's username
+    private_key - key to decrypt incoming messages and get public key,
+                  shouldn't be sent anywhere, generated via generate function
+    """
+    username: str
+    private_key: rsa.RSAPrivateKey = None
+
+    def generate(self):
+        self.private_key = rsa.generate_private_key(
+            public_exponent=65537,
+            key_size=4096
+        )
+
+    def public_key(self):
+        return base64.urlsafe_b64encode(self.private_key.public_key().public_bytes(
+            encoding=serialization.Encoding.DER,
+            format=serialization.PublicFormat.PKCS1
+        ))