degenbot.crypto
===============

.. py:module:: degenbot.crypto

.. autoapi-nested-parse::

   EVM hashing + selector helpers — the stable mirror home for crypto surfaces.

   Provides three public functions:

   - :func:`function_selector` — the 4-byte Solidity selector for a function
     signature. Delegates to :func:`degenbot.contract.get_function_selector`
     (alloy ``keccak256`` under the hood) so the selector computation is owned
     by Rust, not by a Python keccak re-export.
   - :func:`keccak256` — the full 32-byte keccak digest of a byte string.
     Delegates to the Rust FFI ``keccak256`` pyfunction; parity with the
     pre-removal eth_utils vectors is pinned in
     ``tests/test_crypto_parity.py``.
   - :func:`event_topic` — the 32-byte event topic hash for an ABI event entry.
     Computes ``keccak256(canonical_event_signature)`` in Rust from the ABI
     entry dict.





Package Contents
----------------

.. py:function:: function_selector(signature: str) -> bytes

   Return the 4-byte Solidity function selector for ``signature``.

   :param signature: A Solidity function signature, e.g.
                     ``"transfer(address,uint256)"``.

   :returns: The 4-byte selector (e.g. ``b"\\xa9\\x05\\x9c\\xbb"``).


.. py:function:: keccak256(data: bytes) -> bytes

   Return the 32-byte keccak256 digest of ``data``.

   :param data: The input bytes to hash.

   :returns: The 32-byte digest as plain ``bytes`` (callers wanting the 0x-prefixed string
             use :func:`degenbot.utils.bytes.to_0x_hex`).


.. py:function:: event_topic(event_abi_entry: degenbot.types.chain.ABIEvent) -> bytes

   Return the 32-byte event topic hash for an ABI event entry.

   Replaces ``Web3().eth.contract(abi=...).events.<Name>().topic``.
   Computes ``keccak256(canonical_event_signature)`` from the ABI entry
   (the canonical signature omits ``indexed`` markers and uses the
   parameter types in order), so the result is byte-identical to the
   web3-derived topic without importing web3.

   :param event_abi_entry: A single ABI dict with ``"type": "event"``.

   :returns: The 32-byte topic as plain ``bytes``.