Added libs

fspn/utils/ecdh_util.py

@@ -0,0 +1,36 @@
+from cryptography.hazmat.primitives import hashes
+from cryptography.hazmat.primitives.asymmetric import ec
+from cryptography.hazmat.primitives.kdf.hkdf import HKDF
+from cryptography.hazmat.primitives.serialization import PublicFormat, Encoding, load_pem_public_key
+
+def generate_keys():
+    private_key = ec.generate_private_key(
+        ec.SECP384R1()
+    )
+    public_key = private_key.public_key()
+    return public_key, private_key
+
+def generate_shared_key(private_key:ec.EllipticCurvePrivateKey, public_key:ec.EllipticCurvePublicKey):
+    shared_key = private_key.exchange(ec.ECDH(), public_key)
+    return shared_key
+
+def generate_derived_key(shared_key:bytes):
+    derived_key = HKDF(
+        algorithm=hashes.SHA256(),
+        length=32,
+        salt=None,
+        info=None,
+    ).derive(shared_key)
+    return derived_key
+
+def public_key_to_str(public_key:ec.EllipticCurvePublicKey, remove_header_and_footer=False):
+    public_key_str = public_key.public_bytes(Encoding.PEM, PublicFormat.SubjectPublicKeyInfo).decode()
+    if(remove_header_and_footer):
+        public_key_str = public_key_str.replace('-----BEGIN PUBLIC KEY-----\n','')
+        public_key_str = public_key_str.replace('\n-----END PUBLIC KEY-----\n','')
+    return public_key_str
+
+def load_public_key_str(public_key_str:str, removed_header_and_footer=False):
+    if(removed_header_and_footer):
+        public_key_str = f'-----BEGIN PUBLIC KEY-----\n{public_key_str}\n-----END PUBLIC KEY-----\n'
+    return load_pem_public_key(public_key_str.encode())