[enh] #123 add authentication from Scuttlebutt .ssb/secret file

add test and example

duniterpy/key/signing_key.py

@@ -3,6 +3,7 @@ duniter public and private keys
 
 @author: inso, vtexier, Moul
 """
+import base64
 import re
 from typing import Optional, Union, TypeVar, Type
 
@@ -469,3 +470,30 @@ Data: {data}""".format(
                     version=version, data=ewif_key
                 )
             )
+
+    @classmethod
+    def from_ssb_file(cls: Type[SigningKeyType], path: str) -> SigningKeyType:
+        """
+        Return SigningKey instance from ScuttleButt .ssb/secret file
+
+        :param path: Path to Scuttlebutt secret file
+        """
+        with open(path, "r") as fh:
+            ssb_content = fh.read()
+
+        # check data field
+        regex = re.compile(
+            '{\\s*"curve": "ed25519",\\s*"public": "(.+)\\.ed25519",\\s*"private":\\s*"(.+)\\.ed25519",\\s*"id":\\s*"@\\1.ed25519"\\s*}',
+            re.MULTILINE,
+        )
+        match = re.search(regex, ssb_content)
+        if not match:
+            raise Exception("Error: Bad scuttlebutt secret file")
+
+        # capture ssb secret key
+        secret = match.groups()[1]
+
+        # extract seed from secret
+        seed = bytes(base64.b64decode(secret)[0:32])
+
+        return cls(seed)

examples/load_scuttlebutt_file.py

+import sys
+
+from duniterpy.key import SigningKey
+
+if __name__ == "__main__":
+
+    if len(sys.argv) < 2:
+        print(
+            """
+        Usage:
+            python load_scuttlebutt_file.py FILEPATH
+        """
+        )
+
+    # capture filepath argument
+    scuttlebutt_filepath = sys.argv[1]
+
+    # create SigningKey instance from file
+    signing_key_instance = SigningKey.from_ssb_file(
+        scuttlebutt_filepath
+    )  # type: SigningKey
+
+    # print pubkey
+    print("Public key from scuttlebutt file: {}".format(signing_key_instance.pubkey))

tests/key/test_signing_key.py

@@ -93,3 +93,37 @@ class TestSigningKey(unittest.TestCase):
         self.assertEqual(sign_key_test.sk, sign_key_load.sk)
         self.assertEqual(sign_key_test.pubkey, sign_key_load.pubkey)
         self.assertEqual(sign_key_test.vk, sign_key_load.vk)
+
+    def test_load_ssb_file(self):
+        dummy_content = """
+        # comments
+        #
+        #
+        
+        {
+            "curve": "ed25519",
+            "public": "dGVzdHRlc3R0ZXN0dGV0c3RldHN0dGV0c3RldGV0ZXRldHN0ZXR0c3RldHN0dGV0c3Q=.ed25519",
+            "private": "dGVzdHRlc3R0ZXN0dGV0c3RldHN0dGV0c3RldGV0ZXRldHN0ZXR0c3RldHN0dGV0c3Q==.ed25519",
+            "id": "@qJ8qVfXU2mIWG9WfKIRsd6GDscQlErzPHsxzHcyQMWQ=.ed25519"
+        }
+        
+        #
+        # comments
+        """
+
+        # create dummy .ssb/secret file
+        with open(TEST_FILE_PATH, "w") as fh:
+            fh.write(dummy_content)
+        # test load file
+        sign_key_load = SigningKey.from_credentials_file(TEST_FILE_PATH)
+        self.assertEqual(
+            sign_key_load.pubkey, "FAhCeyWq2Ni2xZS3hmYk5w95f8ELxNhUVvU5VB2LXy49"
+        )
+        self.assertEqual(
+            sign_key_load.sk.hex(),
+            "f2f7ae68635dba3455390a74ca0811e4c06142229bb58556aaa37d5598548c9ed27f4cb2bfadbaf45b61714b896d4639ab90db035aee746611cdd342bdaa8996",
+        )
+        self.assertEqual(
+            sign_key_load.vk.hex(),
+            "d27f4cb2bfadbaf45b61714b896d4639ab90db035aee746611cdd342bdaa8996",
+        )