Add support for asset fingerprint (CIP14) (#294)

* Added extended signing key support for cip8

* Fixed unused imports, flake8 checks pass.

* Fixed mypy error for overloaded variable

* Remove extraneous parameter for verify

* Added ByteString to _restored_typed_primitive

* Added type checking

* Added support for CIP 14

* Added support for ScriptHash and AssetName

* Add import to cips and docs

---------

Co-authored-by: Niels Mündler <[email protected]>

Author: theeldermillenial

docs/source/api/pycardano.cip.rst

@@ -7,3 +7,8 @@ Implementation of Cardano Improvement Proposals (CIPs)
    :members:
    :undoc-members:
    :show-inheritance:
+
+.. automodule:: pycardano.cip.cip14
+   :members:
+   :undoc-members:
+   :show-inheritance:

pycardano/cip/__init__.py

@@ -1,3 +1,4 @@
 # flake8: noqa
 
 from .cip8 import *
+from .cip14 import *

pycardano/cip/cip14.py

@@ -0,0 +1,41 @@
+from typing import Union
+
+from nacl.encoding import RawEncoder
+from nacl.hash import blake2b
+from pycardano.crypto.bech32 import encode
+from pycardano.hash import ScriptHash
+from pycardano.transaction import AssetName
+
+
+def encode_asset(
+    policy_id: Union[ScriptHash, bytes, str], asset_name: Union[AssetName, bytes, str]
+) -> str:
+    """Implementation of CIP14 asset fingerprinting
+
+    This function encodes the asset policy and name into an asset fingerprint, which is
+    bech32 compliant.
+
+    For more information:
+    https://developers.cardano.org/docs/governance/cardano-improvement-proposals/cip-0014/
+
+    Args:
+        policy_id: The asset policy as `ScriptHash`, `bytes`, or a hex `str`
+        asset_name: The asset name as `AssetName`, `bytes`, or a hex `str`
+    """
+    if isinstance(policy_id, str):
+        policy_id = bytes.fromhex(policy_id)
+    elif isinstance(policy_id, ScriptHash):
+        policy_id = policy_id.payload
+
+    if isinstance(asset_name, str):
+        asset_name = bytes.fromhex(asset_name)
+    elif isinstance(asset_name, AssetName):
+        asset_name = asset_name.payload
+
+    asset_hash = blake2b(
+        policy_id + asset_name,
+        digest_size=20,
+        encoder=RawEncoder,
+    )
+
+    return encode("asset", asset_hash)

test/pycardano/test_cip14.py

@@ -0,0 +1,72 @@
+import pytest
+
+from pycardano.cip.cip14 import encode_asset
+from pycardano.hash import ScriptHash
+from pycardano.transaction import AssetName
+
+
+@pytest.mark.parametrize(
+    "input_types", [(str, str), (bytes, bytes), (ScriptHash, AssetName)]
+)
+@pytest.mark.parametrize(
+    "asset",
+    [
+        {
+            "policy_id": "7eae28af2208be856f7a119668ae52a49b73725e326dc16579dcc373",
+            "asset_name": "",
+            "asset_fingerprint": "asset1rjklcrnsdzqp65wjgrg55sy9723kw09mlgvlc3",
+        },
+        {
+            "policy_id": "7eae28af2208be856f7a119668ae52a49b73725e326dc16579dcc37e",
+            "asset_name": "",
+            "asset_fingerprint": "asset1nl0puwxmhas8fawxp8nx4e2q3wekg969n2auw3",
+        },
+        {
+            "policy_id": "1e349c9bdea19fd6c147626a5260bc44b71635f398b67c59881df209",
+            "asset_name": "",
+            "asset_fingerprint": "asset1uyuxku60yqe57nusqzjx38aan3f2wq6s93f6ea",
+        },
+        {
+            "policy_id": "7eae28af2208be856f7a119668ae52a49b73725e326dc16579dcc373",
+            "asset_name": "504154415445",
+            "asset_fingerprint": "asset13n25uv0yaf5kus35fm2k86cqy60z58d9xmde92",
+        },
+        {
+            "policy_id": "1e349c9bdea19fd6c147626a5260bc44b71635f398b67c59881df209",
+            "asset_name": "504154415445",
+            "asset_fingerprint": "asset1hv4p5tv2a837mzqrst04d0dcptdjmluqvdx9k3",
+        },
+        {
+            "policy_id": "1e349c9bdea19fd6c147626a5260bc44b71635f398b67c59881df209",
+            "asset_name": "7eae28af2208be856f7a119668ae52a49b73725e326dc16579dcc373",
+            "asset_fingerprint": "asset1aqrdypg669jgazruv5ah07nuyqe0wxjhe2el6f",
+        },
+        {
+            "policy_id": "7eae28af2208be856f7a119668ae52a49b73725e326dc16579dcc373",
+            "asset_name": "1e349c9bdea19fd6c147626a5260bc44b71635f398b67c59881df209",
+            "asset_fingerprint": "asset17jd78wukhtrnmjh3fngzasxm8rck0l2r4hhyyt",
+        },
+        {
+            "policy_id": "7eae28af2208be856f7a119668ae52a49b73725e326dc16579dcc373",
+            "asset_name": "0000000000000000000000000000000000000000000000000000000000000000",
+            "asset_fingerprint": "asset1pkpwyknlvul7az0xx8czhl60pyel45rpje4z8w",
+        },
+    ],
+)
+def test_encode_asset(asset, input_types):
+    if isinstance(input_types[0], bytes):
+        policy_id = bytes.fromhex(asset["policy_id"])
+        asset_name = bytes.fromhex(asset["asset_name"])
+    elif isinstance(input_types[0], str):
+        policy_id = asset["policy_id"]
+        asset_name = asset["asset_name"]
+
+    if isinstance(input_types[0], ScriptHash):
+        policy_id = ScriptHash(policy_id)
+        asset_name = AssetName(asset_name)
+
+    fingerprint = encode_asset(
+        policy_id=asset["policy_id"], asset_name=asset["asset_name"]
+    )
+
+    assert fingerprint == asset["asset_fingerprint"]