Added option for modifying JWT header (#5)

* Added option for modifying JWT header Signed-off-by: Daniel Fett <[email protected]> * Make exception for JSON serialization; add test case Signed-off-by: Daniel Fett <[email protected]> * Revert "Make exception for JSON serialization; add test case" This reverts commit 06ca411. Signed-off-by: Daniel Fett <[email protected]> --------- Signed-off-by: Daniel Fett <[email protected]> Co-authored-by: Daniel Fett <[email protected]>
openwallet-foundation-labs · Oct 4, 2023 · 23f9d1d · 23f9d1d
1 parent 0d857bf
commit 23f9d1d
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Showing 7 changed files with 71 additions and 8 deletions.
diff --git a/src/sd_jwt/bin/generate.py b/src/sd_jwt/bin/generate.py
@@ -39,6 +39,7 @@ def generate_test_case_data(settings: Dict, testcase_path: Path, type: str):
     use_decoys = testcase.get("add_decoy_claims", False)
     serialization_format = testcase.get("serialization_format", "compact")
     include_default_claims = testcase.get("include_default_claims", True)
+    extra_header_parameters = testcase.get("extra_header_parameters", None)
 
     claims = {}
     if include_default_claims:
@@ -58,6 +59,7 @@ def generate_test_case_data(settings: Dict, testcase_path: Path, type: str):
         demo_keys["holder_key"] if testcase.get("key_binding", False) else None,
         add_decoy_claims=use_decoys,
         serialization_format=serialization_format,
+        extra_header_parameters=extra_header_parameters,
     )
 
     ### Produce SD-JWT-R for selected example
@@ -81,7 +83,7 @@ def generate_test_case_data(settings: Dict, testcase_path: Path, type: str):
 
     # Define a function to check the issuer and retrieve the
     # matching public key
-    def cb_get_issuer_key(issuer):
+    def cb_get_issuer_key(issuer, header_parameters):
         # Do not use in production - this allows to use any issuer name for demo purposes
         if issuer == claims.get("iss", None):
             return demo_keys["issuer_public_key"]

diff --git a/src/sd_jwt/common.py b/src/sd_jwt/common.py
@@ -33,7 +33,7 @@ def __init__(self, error_location: any):
 
 
 class SDJWTCommon:
-    SD_JWT_HEADER = None  # "sd+jwt"
+    SD_JWT_TYP_HEADER = None  # "sd+jwt"
     KB_JWT_TYP_HEADER = "kb+jwt"
     JWS_KEY_DISCLOSURES = "disclosures"
     JWS_KEY_KB_JWT = "kb_jwt"

diff --git a/src/sd_jwt/issuer.py b/src/sd_jwt/issuer.py
@@ -36,6 +36,7 @@ def __init__(
         sign_alg=None,
         add_decoy_claims: bool = False,
         serialization_format: str = "compact",
+        extra_header_parameters: Dict = None,
     ):
         super().__init__(serialization_format=serialization_format)
 
@@ -44,6 +45,7 @@ def __init__(
         self._holder_key = holder_key
         self._sign_alg = sign_alg or DEFAULT_SIGNING_ALG
         self._add_decoy_claims = add_decoy_claims
+        self._extra_header_parameters = extra_header_parameters
 
         self.ii_disclosures = []
         self.decoy_digests = []
@@ -168,8 +170,10 @@ def _create_signed_jws(self):
 
         # Assemble protected headers
         _protected_headers = {"alg": self._sign_alg}
-        if self.SD_JWT_HEADER:
-            _protected_headers["typ"] = self.SD_JWT_HEADER
+        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)
 
         self.sd_jwt.add_signature(
             self._issuer_key,

diff --git a/src/sd_jwt/verifier.py b/src/sd_jwt/verifier.py
@@ -21,7 +21,7 @@ class SDJWTVerifier(SDJWTCommon):
     def __init__(
         self,
         sd_jwt_presentation: str,
-        cb_get_issuer_key: Callable[[str], str],
+        cb_get_issuer_key: Callable[[str, Dict], str],
         expected_aud: Union[str, None] = None,
         expected_nonce: Union[str, None] = None,
         serialization_format: str = "compact",
@@ -57,7 +57,8 @@ def _verify_sd_jwt(
         parsed_input_sd_jwt.deserialize(self._unverified_input_sd_jwt)
 
         unverified_issuer = self._unverified_input_sd_jwt_payload.get("iss", None)
-        issuer_public_key = cb_get_issuer_key(unverified_issuer)
+        unverified_header_parameters = parsed_input_sd_jwt.jose_header
+        issuer_public_key = cb_get_issuer_key(unverified_issuer, unverified_header_parameters)
         parsed_input_sd_jwt.verify(issuer_public_key, alg=sign_alg)
 
         self._sd_jwt_payload = loads(parsed_input_sd_jwt.payload.decode("utf-8"))

diff --git a/tests/test_disclose_all_shortcut.py b/tests/test_disclose_all_shortcut.py
@@ -10,6 +10,7 @@ def test_e2e(testcase, settings):
     demo_keys = get_jwk(settings["key_settings"], True, seed)
     use_decoys = testcase.get("add_decoy_claims", False)
     serialization_format = testcase.get("serialization_format", "compact")
+    extra_header_parameters = testcase.get("extra_header_parameters", None)
 
     # Issuer: Produce SD-JWT and issuance format for selected example
 
@@ -23,6 +24,7 @@ def test_e2e(testcase, settings):
         demo_keys["holder_key"] if testcase.get("key_binding", False) else None,
         add_decoy_claims=use_decoys,
         serialization_format=serialization_format,
+        extra_header_parameters=extra_header_parameters,
     )
 
     output_issuance = sdjwt_at_issuer.sd_jwt_issuance
@@ -32,9 +34,12 @@ def test_e2e(testcase, settings):
     output_holder = output_issuance
 
     # Verifier
-    def cb_get_issuer_key(issuer):
+    sdjwt_header_parameters = {}
+    def cb_get_issuer_key(issuer, header_parameters):
+        sdjwt_header_parameters.update(header_parameters)
         return demo_keys["issuer_public_key"]
 
+
     sdjwt_at_verifier = SDJWTVerifier(
         output_holder,
         cb_get_issuer_key,
@@ -52,3 +57,10 @@ def cb_get_issuer_key(issuer):
         expected_claims["cnf"] = {"jwk": demo_keys["holder_key"].export_public(as_dict=True)}
 
     assert verified == expected_claims
+
+    expected_header_parameters = {
+        "alg": testcase.get("sign_alg", "ES256")
+    }
+    expected_header_parameters.update(extra_header_parameters or {})
+
+    assert sdjwt_header_parameters == expected_header_parameters
diff --git a/tests/test_e2e_testcases.py b/tests/test_e2e_testcases.py
@@ -10,6 +10,7 @@ def test_e2e(testcase, settings):
     demo_keys = get_jwk(settings["key_settings"], True, seed)
     use_decoys = testcase.get("add_decoy_claims", False)
     serialization_format = testcase.get("serialization_format", "compact")
+    extra_header_parameters = testcase.get("extra_header_parameters", None)
 
     # Issuer: Produce SD-JWT and issuance format for selected example
 
@@ -23,6 +24,7 @@ def test_e2e(testcase, settings):
         demo_keys["holder_key"] if testcase.get("key_binding", False) else None,
         add_decoy_claims=use_decoys,
         serialization_format=serialization_format,
+        extra_header_parameters=extra_header_parameters,
     )
 
     output_issuance = sdjwt_at_issuer.sd_jwt_issuance
@@ -45,7 +47,9 @@ def test_e2e(testcase, settings):
     output_holder = sdjwt_at_holder.sd_jwt_presentation
 
     # Verifier
-    def cb_get_issuer_key(issuer):
+    sdjwt_header_parameters = {}
+    def cb_get_issuer_key(issuer, header_parameters):
+        sdjwt_header_parameters.update(header_parameters)
         return demo_keys["issuer_public_key"]
 
     sdjwt_at_verifier = SDJWTVerifier(
@@ -68,3 +72,10 @@ def cb_get_issuer_key(issuer):
         }
 
     assert verified == expected_claims
+
+    expected_header_parameters = {
+        "alg": testcase.get("sign_alg", "ES256")
+    }
+    expected_header_parameters.update(extra_header_parameters or {})
+
+    assert sdjwt_header_parameters == expected_header_parameters
diff --git a/tests/testcases/header_mod/specification.yml b/tests/testcases/header_mod/specification.yml
@@ -0,0 +1,33 @@
+user_claims:
+  !sd sub: john_doe_42
+  !sd given_name: John
+  !sd family_name: Doe
+  !sd email: [email protected]
+  !sd phone_number: +1-202-555-0101
+  !sd address:
+    street_address: 123 Main St
+    locality: Anytown
+    region: Anystate
+    country: US
+  !sd birthdate: "1940-01-01"
+
+holder_disclosed_claims:
+  given_name: true
+  family_name: true
+  address: true
+
+extra_header_parameters:
+  kid: 42
+
+expect_verified_user_claims:
+  given_name: John
+  family_name: Doe
+  address: 
+    street_address: 123 Main St
+    locality: Anytown
+    region: Anystate
+    country: US
+
+key_binding: True
+
+serialization_format: compact