Add to_jwk static method to ECAlgorithm (#732)

* Add to_jwk static method to ECAlgorithm

* [pre-commit.ci] auto fixes from pre-commit.com hooks

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* Add in tests for ECAlgorithm.to_jwk

* [pre-commit.ci] auto fixes from pre-commit.com hooks

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* Add to_jwk pull request to changelog

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

1 files changed, 35 insertions, 0 deletions

diff --git a/jwt/algorithms.py b/jwt/algorithms.py
index 46a1a53..4c178a3 100644
--- a/jwt/algorithms.py
+++ b/jwt/algorithms.py
@@ -440,6 +440,41 @@ if has_crypto:
                 return False
 
         @staticmethod
+        def to_jwk(key_obj):
+
+            if isinstance(key_obj, EllipticCurvePrivateKey):
+                public_numbers = key_obj.public_key().public_numbers()
+            elif isinstance(key_obj, EllipticCurvePublicKey):
+                public_numbers = key_obj.public_numbers()
+            else:
+                raise InvalidKeyError("Not a public or private key")
+
+            if isinstance(key_obj.curve, ec.SECP256R1):
+                crv = "P-256"
+            elif isinstance(key_obj.curve, ec.SECP384R1):
+                crv = "P-384"
+            elif isinstance(key_obj.curve, ec.SECP521R1):
+                crv = "P-521"
+            elif isinstance(key_obj.curve, ec.SECP256K1):
+                crv = "secp256k1"
+            else:
+                raise InvalidKeyError(f"Invalid curve: {key_obj.curve}")
+
+            obj = {
+                "kty": "EC",
+                "crv": crv,
+                "x": to_base64url_uint(public_numbers.x).decode(),
+                "y": to_base64url_uint(public_numbers.y).decode(),
+            }
+
+            if isinstance(key_obj, EllipticCurvePrivateKey):
+                obj["d"] = to_base64url_uint(
+                    key_obj.private_numbers().private_value
+                ).decode()
+
+            return json.dumps(obj)
+
+        @staticmethod
         def from_jwk(jwk):
             try:
                 if isinstance(jwk, str):