fix: improve NanoTDF support

src/otdf_python/cli.py

@@ -201,6 +201,13 @@ def create_nano_tdf_config(sdk: SDK, args) -> NanoTDFConfig:
         kas_endpoints = parse_kas_endpoints(args.kas_endpoint)
         kas_info_list = [KASInfo(url=kas_url) for kas_url in kas_endpoints]
         config.kas_info_list.extend(kas_info_list)
+    elif args.platform_url:
+        # If no explicit KAS endpoint provided, derive from platform URL
+        # This matches the default KAS path convention
+        kas_url = args.platform_url.rstrip("/") + "/kas"
+        logger.debug(f"Deriving KAS endpoint from platform URL: {kas_url}")
+        kas_info = KASInfo(url=kas_url)
+        config.kas_info_list.append(kas_info)
 
     if hasattr(args, "policy_binding") and args.policy_binding:
         if args.policy_binding.lower() == "ecdsa":

src/otdf_python/ecc_mode.py

@@ -1,4 +1,14 @@
+from typing import ClassVar
+
+
 class ECCMode:
+    _CURVE_MAP: ClassVar[dict[str, int]] = {
+        "secp256r1": 0,
+        "secp384r1": 1,
+        "secp521r1": 2,
+        "secp256k1": 3,
+    }
+
     def __init__(self, curve_mode: int = 0, use_ecdsa_binding: bool = False):
         self.curve_mode = curve_mode
         self.use_ecdsa_binding = use_ecdsa_binding
@@ -15,18 +25,43 @@ def set_elliptic_curve(self, curve_mode: int):
     def get_elliptic_curve_type(self) -> int:
         return self.curve_mode
 
+    def get_curve_name(self) -> str:
+        """Get the curve name as a string (e.g., 'secp256r1')."""
+        for name, mode in self._CURVE_MAP.items():
+            if mode == self.curve_mode:
+                return name
+        # Default to secp256r1 if not found
+        return "secp256r1"
+
     @staticmethod
     def get_ec_compressed_pubkey_size(curve_type: int) -> int:
-        # 0: secp256r1, 1: secp384r1, 2: secp521r1
+        # 0: secp256r1, 1: secp384r1, 2: secp521r1, 3: secp256k1
         if curve_type == 0:
-            return 33
+            return 33  # secp256r1
         elif curve_type == 1:
-            return 49
+            return 49  # secp384r1
         elif curve_type == 2:
-            return 67
+            return 67  # secp521r1
+        elif curve_type == 3:
+            return 33  # secp256k1 (same size as secp256r1)
         else:
             raise ValueError("Unsupported ECC algorithm.")
 
     def get_ecc_mode_as_byte(self) -> int:
         # Most significant bit: use_ecdsa_binding, lower 3 bits: curve_mode
         return ((1 if self.use_ecdsa_binding else 0) << 7) | (self.curve_mode & 0x07)
+
+    @staticmethod
+    def from_string(curve_str: str) -> "ECCMode":
+        """Create ECCMode from curve string like 'secp256r1' or 'secp384r1', or policy binding type like 'gmac' or 'ecdsa'."""
+        # Handle policy binding types
+        if curve_str.lower() == "gmac":
+            return ECCMode(0, False)  # GMAC binding with default secp256r1 curve
+        elif curve_str.lower() == "ecdsa":
+            return ECCMode(0, True)  # ECDSA binding with default secp256r1 curve
+
+        # Handle curve names
+        curve_mode = ECCMode._CURVE_MAP.get(curve_str.lower())
+        if curve_mode is None:
+            raise ValueError(f"Unsupported curve string: '{curve_str}'")
+        return ECCMode(curve_mode, False)