mirror of
https://github.com/trezor/trezor-firmware.git
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51 lines
1.4 KiB
Python
51 lines
1.4 KiB
Python
import ustruct
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from trezor.crypto import base32
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from trezor.wire import ProcessError
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def public_key_from_address(address: str) -> bytes:
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"""Extracts public key from an address
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Stellar address is in format:
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<1-byte version> <32-bytes ed25519 public key> <2-bytes CRC-16 checksum>
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"""
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b = base32.decode(address)
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_crc16_checksum_verify(b[:-2], b[-2:])
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return b[1:-2]
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def address_from_public_key(pubkey: bytes):
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"""Returns the base32-encoded version of public key bytes (G...)"""
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address = bytearray()
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address.append(6 << 3) # version -> 'G'
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address.extend(pubkey)
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address.extend(_crc16_checksum(bytes(address))) # checksum
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return base32.encode(address)
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def _crc16_checksum_verify(data: bytes, checksum: bytes):
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if _crc16_checksum(data) != checksum:
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raise ProcessError("Invalid address checksum")
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def _crc16_checksum(data: bytes) -> bytes:
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"""Returns the CRC-16 checksum of bytearray bytes
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Ported from Java implementation at: http://introcs.cs.princeton.edu/java/61data/CRC16CCITT.java.html
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Initial value changed to 0x0000 to match Stellar configuration.
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"""
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crc = 0x0000
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polynomial = 0x1021
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for byte in data:
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for i in range(8):
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bit = (byte >> (7 - i) & 1) == 1
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c15 = (crc >> 15 & 1) == 1
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crc <<= 1
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if c15 ^ bit:
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crc ^= polynomial
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return ustruct.pack("<H", crc & 0xFFFF)
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