Add generic signautre verification

aeternity/signing.py

@@ -5,7 +5,7 @@
 import uuid
 
 from nacl.encoding import RawEncoder, HexEncoder
-from nacl.signing import SigningKey
+from nacl.signing import SigningKey, VerifyKey
 from nacl.exceptions import CryptoError
 from nacl.pwhash import argon2id
 from nacl import secret, utils as nacl_utils
@@ -213,3 +213,20 @@ def keystore_open(k, password):
     encrypted = bytes.fromhex(k.get("crypto", {}).get("ciphertext"))
     private_key = box.decrypt(encrypted, nonce=nonce, encoder=RawEncoder)
     return private_key
+
+
+def is_signature_valid(account_id, signature, data: bytes) -> bool:
+    """
+    Verify the signature of a message
+    :param account_id: the account id signing the message
+    :param signature: the signature of the messagfe
+    :param data: the message that has been signed
+    :return: true if the signature for the message is valid, false otherwise
+    """
+    try:
+        id = hashing.decode(account_id) if isinstance(account_id, str) else account_id
+        sg = hashing.decode(signature) if isinstance(signature, str) else signature
+        VerifyKey(id).verify(data, sg)
+        return True
+    except Exception as e:
+        return False

tests/test_signing.py

@@ -1,7 +1,8 @@
 from pytest import raises
 from tests import ACCOUNT, NODE_CLI, tempdir, TEST_FEE, TEST_TTL
-from aeternity.signing import Account
+from aeternity.signing import Account, is_signature_valid
 from aeternity.utils import is_valid_hash
+from aeternity import hashing
 import os
 
 
@@ -71,3 +72,26 @@ def test_signing_keystore_save_load_wrong_pwd():
         with raises(ValueError):
             a = Account.from_keystore(path, "nononon")
             assert a.get_address() == ACCOUNT.get_address()
+
+
+def test_signing_is_signature_valid():
+    sg_ae = "sg_6cXUU8rimh8B3byLHJA9SaG29uRggtyrpGi5YAFiL9cJUoVtMX4P4kpd4UPTjiGXYSaquSN3gidJ73U8CtfweQ14GFgsC"
+    account_id = "ak_axjxzUJpj9siJDQKZrBFNTvQLR2JwcZoVPjgdCQdnGUtwf66r"
+
+    sg_b64 = "KuZVJ8kK6xCmujLfd8AjU3IfENn1WwcQRA0hI/WWzyXp97zerFg9XRx/ICHcHRGmvxstsul/QEDma2uHf6DIAEcr8Vs="
+    account_b64 = "TRza0pA9oaZw7tltPULKlkRaGV2qXT9vJx9q2HGY4Lom4qR3"
+
+    msg = "aeternity".encode("utf-8")
+
+    assert is_signature_valid(account_id, sg_ae, msg)
+    assert is_signature_valid(
+        hashing._base64_decode(account_b64),
+        hashing._base64_decode(sg_b64),
+        msg)
+
+    msg = "wrong".encode("utf-8")
+    assert not is_signature_valid(account_id, sg_ae, msg)
+    assert not is_signature_valid(
+        hashing._base64_decode(account_b64),
+        hashing._base64_decode(sg_b64),
+        msg)