Merge branch 'Protocol_00' of git.gmoker.com:icing/monorepo into Protocol_00

protocol_prototype/IcingProtocol.drawio

@@ -1,4 +1,4 @@
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@@ -260,7 +260,7 @@
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protocol_prototype/crypto_utils.py

@@ -1,11 +1,8 @@
 import os
-from cryptography.hazmat.primitives import hashes
-from cryptography.hazmat.primitives.asymmetric import ec
-from cryptography.hazmat.primitives.asymmetric.ec import ECDH
-from cryptography.hazmat.primitives import serialization
-from cryptography.hazmat.primitives.asymmetric import utils
 from cryptography.exceptions import InvalidSignature
-
+from cryptography.hazmat.primitives import hashes, serialization
+from cryptography.hazmat.primitives.asymmetric import ec, utils
+from cryptography.hazmat.primitives.asymmetric.utils import decode_dss_signature, encode_dss_signature
 
 def generate_identity_keys():
     """
@@ -79,3 +76,26 @@ def compute_ecdh_shared_key(private_key, peer_pubkey_bytes: bytes) -> bytes:
     peer_public_key = peer_public_numbers.public_key()
     shared_key = private_key.exchange(ec.ECDH(), peer_public_key)
     return shared_key
+
+
+def der_to_raw(der_sig: bytes) -> bytes:
+    """
+    Convert a DER-encoded ECDSA signature to a raw 64-byte signature (r||s),
+    where each component is padded to 32 bytes.
+    """
+    r, s = decode_dss_signature(der_sig)
+    r_bytes = r.to_bytes(32, byteorder='big')
+    s_bytes = s.to_bytes(32, byteorder='big')
+    return r_bytes + s_bytes
+
+
+def raw_signature_to_der(raw_sig: bytes) -> bytes:
+    """
+    Convert a raw signature (64 bytes, concatenated r||s) to DER-encoded signature.
+    """
+    if len(raw_sig) != 64:
+        raise ValueError("Raw signature must be 64 bytes (r||s).")
+    from cryptography.hazmat.primitives.asymmetric.utils import encode_dss_signature
+    r = int.from_bytes(raw_sig[:32], 'big')
+    s = int.from_bytes(raw_sig[32:], 'big')
+    return encode_dss_signature(r, s)

protocol_prototype/protocol.py

@@ -2,6 +2,7 @@ import random
 import time
 import threading
 from typing import List, Dict, Any
+from crypto_utils import raw_signature_to_der
 
 from crypto_utils import (
     generate_identity_keys,
@@ -306,9 +307,8 @@ class IcingProtocol:
 
     def generate_ecdhe(self, index: int):
         """
-        Formerly 'respond_to_handshake' - this verifies the inbound ephemeral signature
-        and computes the ECDH shared secret, storing it in self.shared_secret.
-        It does NOT send a handshake back.
+        Formerly 'respond_to_handshake'. Verifies the inbound ephemeral signature
+        and computes the ECDH shared secret, updating PFS history.
         """
         if index < 0 or index >= len(self.inbound_messages):
             print(f"{RED}[ERROR]{RESET} Invalid index {index}.")
@@ -321,23 +321,30 @@ class IcingProtocol:
         ephemeral_pub = msg["parsed"]["ephemeral_pub"]
         ephemeral_sig = msg["parsed"]["ephemeral_sig"]
 
-        # Verify ephemeral signature
-        if not self.peer_identity_pubkey_obj:
-            print(f"{RED}[ERROR]{RESET} Peer identity not set, cannot verify ephemeral signature.")
-            return
-        ok = verify_signature(self.peer_identity_pubkey_obj, ephemeral_sig, ephemeral_pub)
-        if not ok:
-            print(f"{RED}[ERROR]{RESET} Ephemeral signature is invalid.")
-            return
-        print(f"{GREEN}[OK]{RESET} Ephemeral signature verified successfully.")
-
-        # If we have ephemeral_privkey, compute ECDH shared key
-        if self.ephemeral_privkey:
-            shared = compute_ecdh_shared_key(self.ephemeral_privkey, ephemeral_pub)
-            self.shared_secret = shared.hex()
-            print(f"{GREEN}[OK]{RESET} Derived ECDH shared key = {self.shared_secret}")
+        # Use our raw_signature_to_der wrapper only if signature is 64 bytes.
+        # Otherwise, assume the signature is already DER-encoded.
+        from crypto_utils import raw_signature_to_der
+        if len(ephemeral_sig) == 64:
+            sig_der = raw_signature_to_der(ephemeral_sig)
         else:
-            print(f"{YELLOW}[WARN]{RESET} No ephemeral_privkey available, cannot compute ECDH shared key.")
+            sig_der = ephemeral_sig
+
+        ok = verify_signature(self.peer_identity_pubkey_obj, sig_der, ephemeral_pub)
+        if not ok:
+            print(f"{RED}[ERROR]{RESET} Ephemeral signature invalid.")
+            return
+        print(f"{GREEN}[OK]{RESET} Ephemeral signature verified.")
+
+        if not self.ephemeral_privkey:
+            print(f"{YELLOW}[WARN]{RESET} No ephemeral_privkey available, cannot compute shared secret.")
+            return
+        shared = compute_ecdh_shared_key(self.ephemeral_privkey, ephemeral_pub)
+        self.shared_secret = shared.hex()
+        print(f"{GREEN}[OK]{RESET} Computed ECDH shared key = {self.shared_secret}")
+
+        old_session, _ = self.pfs_history.get(self.peer_identity_pubkey_bytes, (-1, ""))
+        new_session = 1 if old_session < 0 else old_session + 1
+        self.pfs_history[self.peer_identity_pubkey_bytes] = (new_session, self.shared_secret)
 
     # -------------------------------------------------------------------------
     # Utility