# Copyright (c) 2026 Emanuele Bellocchia
#
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# of this software and associated documentation files (the "Software"), to deal
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# furnished to do so, subject to the following conditions:
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# THE SOFTWARE.
"""Module for Ethereum address encoding/decoding."""
# Imports
from typing import Any, Union
from typing_extensions import override
from bip_utils.addr.addr_dec_utils import AddrDecUtils
from bip_utils.addr.addr_key_validator import AddrKeyValidator
from bip_utils.addr.iaddr_decoder import IAddrDecoder
from bip_utils.addr.iaddr_encoder import IAddrEncoder
from bip_utils.coin_conf import CoinsConf
from bip_utils.ecc import IPublicKey
from bip_utils.utils.crypto import Kekkak256
from bip_utils.utils.misc import BytesUtils
class EthAddrConst:
"""Class container for Ethereum address constants."""
# Start byte
START_BYTE: int = 24
# Address length
ADDR_LEN: int = 40
class _EthAddrUtils:
"""Class container for Ethereum address utility functions."""
@staticmethod
def ChecksumEncode(addr: str) -> str:
"""
Checksum encode the specified address.
Args:
addr (str): Address string
Returns:
str: Checksum encoded address
"""
# Compute address digest
addr_hex_digest = BytesUtils.ToHexString(Kekkak256.QuickDigest(addr.lower()))
# Encode it
enc_addr = [c.upper() if (int(addr_hex_digest[i], 16) >= 8) else c.lower() for i, c in enumerate(addr)]
return "".join(enc_addr)
class EthAddrDecoder(IAddrDecoder):
"""
Ethereum address decoder class.
It allows the Ethereum address decoding.
"""
@override
@staticmethod
def DecodeAddr(addr: str,
**kwargs: Any) -> bytes:
"""
Decode an Ethereum address to bytes.
Args:
addr (str): Address string
Other Parameters:
skip_chksum_enc (bool, optional): True to skip checksum encoding verification, false otherwise (default)
Returns:
bytes: Public key hash bytes
Raises:
ValueError: If the address encoding is not valid
"""
skip_chksum_enc = kwargs.get("skip_chksum_enc", False)
# Validate and remove prefix
addr_no_prefix = AddrDecUtils.ValidateAndRemovePrefix(addr,
CoinsConf.Ethereum.ParamByKey("addr_prefix"))
# Validate length
AddrDecUtils.ValidateLength(addr_no_prefix, EthAddrConst.ADDR_LEN)
# Check checksum encoding
if not skip_chksum_enc and addr_no_prefix != _EthAddrUtils.ChecksumEncode(addr_no_prefix):
raise ValueError("Invalid checksum encoding")
return BytesUtils.FromHexString(addr_no_prefix)
class EthAddrEncoder(IAddrEncoder):
"""
Ethereum address encoder class.
It allows the Ethereum address encoding.
"""
@override
@staticmethod
def EncodeKey(pub_key: Union[bytes, IPublicKey],
**kwargs: Any) -> str:
"""
Encode a public key to Ethereum address.
Args:
pub_key (bytes or IPublicKey): Public key bytes or object
Other Parameters:
skip_chksum_enc (bool, optional): True to skip checksum encoding, false otherwise (default)
Returns:
str: Address string
Raises:
ValueError: If the public key is not valid
TypeError: If the public key is not secp256k1
"""
skip_chksum_enc = kwargs.get("skip_chksum_enc", False)
pub_key_obj = AddrKeyValidator.ValidateAndGetSecp256k1Key(pub_key)
# First byte of the uncompressed key (i.e. 0x04) is not needed
kekkak_hex = BytesUtils.ToHexString(Kekkak256.QuickDigest(pub_key_obj.RawUncompressed().ToBytes()[1:]))
addr = kekkak_hex[EthAddrConst.START_BYTE:]
return CoinsConf.Ethereum.ParamByKey("addr_prefix") + (_EthAddrUtils.ChecksumEncode(addr)
if not skip_chksum_enc
else addr)
# Deprecated: only for compatibility, Encoder class shall be used instead
EthAddr = EthAddrEncoder