feat: protected header by construction kwarg and small linting

pyproject.toml

@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "sd-jwt"
-version = "0.9.1"
+version = "0.10.0"
 description = "The reference implementation of the IETF SD-JWT specification."
 authors = ["Daniel Fett <[email protected]>"]
 readme = "README.md"

src/sd_jwt/__init__.py

@@ -1 +1 @@
-__version__ = "0.9.1"
+__version__ = "0.10.0"

src/sd_jwt/common.py

@@ -33,7 +33,7 @@ def __init__(self, error_location: any):
 
 
 class SDJWTCommon:
-    SD_JWT_TYP_HEADER = None  # "sd+jwt"
+    SD_JWT_HEADER = "sd+jwt"
     KB_JWT_TYP_HEADER = "kb+jwt"
     JWS_KEY_DISCLOSURES = "disclosures"
     JWS_KEY_KB_JWT = "kb_jwt"
@@ -91,14 +91,14 @@ def _create_hash_mappings(self, disclosurses_list: List):
             decoded_disclosure = loads(
                 self._base64url_decode(disclosure).decode("utf-8")
             )
-            hash = self._b64hash(disclosure.encode("ascii"))
-            if hash in self._hash_to_decoded_disclosure:
+            _hash = self._b64hash(disclosure.encode("ascii"))
+            if _hash in self._hash_to_decoded_disclosure:
                 raise ValueError(
-                    f"Duplicate disclosure hash {hash} for disclosure {decoded_disclosure}"
+                    f"Duplicate disclosure hash {_hash} for disclosure {decoded_disclosure}"
                 )
 
-            self._hash_to_decoded_disclosure[hash] = decoded_disclosure
-            self._hash_to_disclosure[hash] = disclosure
+            self._hash_to_decoded_disclosure[_hash] = decoded_disclosure
+            self._hash_to_disclosure[_hash] = disclosure
 
     def _check_for_sd_claim(self, the_object):
         # Recursively check for the presence of the _sd claim, also

src/sd_jwt/holder.py

@@ -94,7 +94,7 @@ def _select_disclosures_list(self, sd_jwt_claims, claims_to_disclose):
             zip_longest(claims_to_disclose, sd_jwt_claims, fillvalue=None)
         ):
             if (
-                type(element) is dict
+                isinstance(element, dict)
                 and len(element) == 1
                 and SD_LIST_PREFIX in element
                 and type(element[SD_LIST_PREFIX]) is str
@@ -116,11 +116,11 @@ def _select_disclosures_list(self, sd_jwt_claims, claims_to_disclose):
                     continue
 
                 self.hs_disclosures.append(self._hash_to_disclosure[digest_to_check])
-                if type(disclosure_value) is dict:
+                if isinstance(disclosure_value, dict):
                     if claims_to_disclose_element is True:
                         # Tolerate a "True" for a disclosure of an object
                         claims_to_disclose_element = {}
-                    if not type(claims_to_disclose_element) is dict:
+                    if not isinstance(claims_to_disclose_element, dict):
                         raise ValueError(
                             f"To disclose object elements in arrays, provide an object (can be empty).\n"
                             f"Found {claims_to_disclose_element} instead.\n"
@@ -130,11 +130,11 @@ def _select_disclosures_list(self, sd_jwt_claims, claims_to_disclose):
                     self._select_disclosures(
                         disclosure_value, claims_to_disclose_element
                     )
-                elif type(disclosure_value) is list:
+                elif isinstance(disclosure_value, list):
                     if claims_to_disclose_element is True:
                         # Tolerate a "True" for a disclosure of an array
                         claims_to_disclose_element = []
-                    if not type(claims_to_disclose_element) is list:
+                    if not isinstance(claims_to_disclose_element, list):
                         raise ValueError(
                             f"To disclose array elements nested in arrays, provide an array (can be empty).\n"
                             f"Found {claims_to_disclose_element} instead.\n"
@@ -155,7 +155,7 @@ def _select_disclosures_dict(self, sd_jwt_claims, claims_to_disclose):
         if claims_to_disclose is True:
             # Tolerate a "True" for a disclosure of an object
             claims_to_disclose = {}
-        if not type(claims_to_disclose) is dict:
+        if not isinstance(claims_to_disclose, dict):
             raise ValueError(
                 f"To disclose object elements, an object must be provided as disclosure information.\n"
                 f"Found {claims_to_disclose} (type {type(claims_to_disclose)}) instead.\n"

src/sd_jwt/issuer.py

@@ -36,7 +36,7 @@ def __init__(
         sign_alg=None,
         add_decoy_claims: bool = False,
         serialization_format: str = "compact",
-        extra_header_parameters: Dict = None,
+        extra_header_parameters: dict = {},
     ):
         super().__init__(serialization_format=serialization_format)
 
@@ -78,21 +78,20 @@ def _create_sd_claims(self, user_claims):
         #
         # If the user claims are a list, apply this function
         # to each item in the list.
-        if type(user_claims) is list:
+        if isinstance(user_claims, list):
             return self._create_sd_claims_list(user_claims)
 
         # If the user claims are a dictionary, apply this function
         # to each key/value pair in the dictionary.
-        elif type(user_claims) is dict:
+        elif isinstance(user_claims, dict):
             return self._create_sd_claims_object(user_claims)
 
         # For other types, assume that the value can be disclosed.
-        else:
-            if isinstance(user_claims, SDObj):
-                raise ValueError(
-                    f"SDObj found in illegal place.\nThe claim value '{user_claims}' should not be wrapped by SDObj."
-                )
-            return user_claims
+        elif isinstance(user_claims, SDObj):
+            raise ValueError(
+                f"SDObj found in illegal place.\nThe claim value '{user_claims}' should not be wrapped by SDObj."
+            )
+        return user_claims
 
     def _create_sd_claims_list(self, user_claims: List):
         # Walk through all elements in the list.
@@ -168,12 +167,13 @@ def _create_signed_jws(self):
 
         self.sd_jwt = JWS(payload=dumps(self.sd_jwt_payload))
 
-        # Assemble protected headers
-        _protected_headers = {"alg": self._sign_alg}
-        if self.SD_JWT_TYP_HEADER:
-            _protected_headers["typ"] = self.SD_JWT_TYP_HEADER
-        if self._extra_header_parameters:
-            _protected_headers.update(self._extra_header_parameters)
+        # Assemble protected headers starting with default
+        _protected_headers = {
+            "alg": self._sign_alg,
+            "typ": self.SD_JWT_HEADER
+        }
+        # override if any
+        _protected_headers.update(self.extra_header_parameters)
 
         self.sd_jwt.add_signature(
             self._issuer_key,