# 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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# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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# THE SOFTWARE.
"""Module for Nimiq address encoding/decoding."""
# Imports
from typing import Any, Union
from typing_extensions import override
from bip_utils.addr.addr_dec_utils import AddrDecUtils, ChecksumPositions
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 Blake2b256
from bip_utils.utils.misc import Base32Decoder, Base32Encoder
class NimAddrConst:
"""Class container for Nimiq address constants."""
# Length of an address group of characters
ADDR_GROUP_LEN: int = 4
# Encoded checksum length
CHECKSUM_ENC_LEN: int = 2
# Alphabet for base32
BASE32_ALPHABET: str = "0123456789ABCDEFGHJKLMNPQRSTUVXY"
# Hash length in bytes
HASH_BYTE_LEN: int = 20
# Encoded hah length
HASH_ENC_LEN: int = 32
class _NimAddrUtils:
"""Class container for Nimiq address utility functions."""
@classmethod
def ComputeChecksum(cls,
addr_base32: str) -> str:
"""
Compute checksum in Nimiq format.
Args:
addr_base32 (str): Address base32 encoded
Returns:
str: Computed checksum encoded to string
"""
# Compute checksum from address encoding
checksum = 0
for c in addr_base32:
val = ord(c) - ord("0") if c.isdigit() else ord(c) - ord("7")
checksum = cls.__AddChecksum(checksum, val)
# Finalize checksum
checksum = cls.__FinalizeChecksum(checksum)
# Convert it to string
return cls.__ChecksumToString(checksum)
@staticmethod
def __ChecksumToString(checksum: int) -> str:
"""
Convert checksum to string.
Args:
checksum (int): Checksum
Returns:
str: Checksum string
"""
return chr(ord("0") + int(checksum / 10)) + chr(ord("0") + (checksum % 10))
@classmethod
def __FinalizeChecksum(cls,
checksum: int) -> int:
"""
Finalize checksum.
Args:
checksum (int): Checksum
Returns:
int: Finalized checksum
"""
return 98 - cls.__AddChecksum(checksum, 232600)
@staticmethod
def __AddChecksum(checksum: int,
val: int) -> int:
"""
Add a value to the checksum.
Args:
checksum (int): Checksum
val (int) : Value to be added
Returns:
int: Resulting checksum
"""
if val == 0:
return (checksum * 10) % 97
remainder = val
while remainder > 0:
checksum *= 10
remainder = int(remainder / 10)
return (checksum + val) % 97
class NimAddrDecoder(IAddrDecoder):
"""
Nimiq address decoder class.
It allows the Nimiq address decoding.
"""
@override
@staticmethod
def DecodeAddr(addr: str,
**kwargs: Any) -> bytes:
"""
Decode an Nimiq address to bytes.
Args:
addr (str): Address string
**kwargs : Not used
Returns:
bytes: Public key hash bytes
Raises:
ValueError: If the address encoding is not valid
"""
# Remove all spaces
addr = addr.replace(" ", "")
# Validate and remove prefix
addr_no_prefix = AddrDecUtils.ValidateAndRemovePrefix(addr, CoinsConf.Nimiq.ParamByKey("addr_prefix"))
# Validate length
AddrDecUtils.ValidateLength(addr_no_prefix,
NimAddrConst.CHECKSUM_ENC_LEN + NimAddrConst.HASH_ENC_LEN)
# Get back checksum and public key hash
pub_key_hash_enc, checksum = AddrDecUtils.SplitPartsByChecksum(
addr_no_prefix,
NimAddrConst.CHECKSUM_ENC_LEN,
ChecksumPositions.BEGINNING
)
# Validate checksum
AddrDecUtils.ValidateChecksum(pub_key_hash_enc, checksum, _NimAddrUtils.ComputeChecksum)
return Base32Decoder.Decode(pub_key_hash_enc, NimAddrConst.BASE32_ALPHABET)
class NimAddrEncoder(IAddrEncoder):
"""
Nimiq address encoder class.
It allows the Nimiq address encoding.
"""
@override
@staticmethod
def EncodeKey(pub_key: Union[bytes, IPublicKey],
**kwargs: Any) -> str:
"""
Encode a public key to Nimiq address.
Args:
pub_key (bytes or IPublicKey): Public key bytes or object
**kwargs : Not used
Returns:
str: Address string
Raises:
ValueError: If the public key is not valid
TypeError: If the public key is not ed25519
"""
pub_key_obj = AddrKeyValidator.ValidateAndGetEd25519Key(pub_key)
pub_key_bytes = pub_key_obj.RawCompressed().ToBytes()[1:]
pub_key_hash_bytes = Blake2b256.QuickDigest(pub_key_bytes)[:NimAddrConst.HASH_BYTE_LEN]
pub_key_hash_enc = Base32Encoder.EncodeNoPadding(pub_key_hash_bytes, NimAddrConst.BASE32_ALPHABET)
pub_key_hash_enc_grouped = " ".join(
pub_key_hash_enc[i:i + NimAddrConst.ADDR_GROUP_LEN]
for i in range(0, len(pub_key_hash_enc), NimAddrConst.ADDR_GROUP_LEN)
)
checksum = _NimAddrUtils.ComputeChecksum(pub_key_hash_enc)
return CoinsConf.Nimiq.ParamByKey("addr_prefix") + checksum + " " + pub_key_hash_enc_grouped
# Deprecated: only for compatibility, Encoder class shall be used instead
NimAddr = NimAddrEncoder