UmbralPublicKeys allow hex serialization

tests/unit/test_umbral_keys.py

@@ -133,6 +133,14 @@ def test_key_encoder_decoder(random_ec_curvebn1):
     assert decoded_key.to_bytes() == umbral_key.to_bytes()
 
 
+def test_public_key_as_hex(random_ec_curvebn1):
+    pubkey = UmbralPrivateKey(random_ec_curvebn1, default_params()).get_pubkey()
+    hex_string = pubkey.hex()
+    decoded_pubkey = UmbralPublicKey.from_hex(hex_string)
+
+    assert pubkey == decoded_pubkey
+
+
 def test_umbral_key_to_cryptography_keys():
     umbral_priv_key = UmbralPrivateKey.gen_key()
     umbral_pub_key = umbral_priv_key.get_pubkey()

umbral/keys.py

@@ -321,6 +321,16 @@ class UmbralPublicKey:
 
         return umbral_pubkey
 
+    def hex(self, is_compressed: bool = True) -> str:
+        """
+        Returns an Umbral public key as hex string.
+        """
+        return self.to_bytes(is_compressed=is_compressed).hex()
+
+    @classmethod
+    def from_hex(cls, hex_string: str) -> 'UmbralPublicKey':
+        return cls.from_bytes(key_bytes=hex_string, decoder=bytes.fromhex)
+
     def to_cryptography_pubkey(self) -> _EllipticCurvePublicKey:
         """
         Returns a cryptography.io EllipticCurvePublicKey from the Umbral key.