mirror of
https://github.com/trezor/trezor-firmware.git
synced 2025-05-04 16:09:05 +00:00
103 lines
3.2 KiB
Python
103 lines
3.2 KiB
Python
# Copyright (c) 2017 Pieter Wuille
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# Copyright (c) 2018 Oskar Hladky
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# Copyright (c) 2018 Pavol Rusnak
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#
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# Permission is hereby granted, free of charge, to any person obtaining a copy
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# of this software and associated documentation files (the "Software"), to deal
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# in the Software without restriction, including without limitation the rights
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# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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# copies of the Software, and to permit persons to whom the Software is
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# furnished to do so, subject to the following conditions:
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#
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# The above copyright notice and this permission notice shall be included in
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# all copies or substantial portions of the Software.
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#
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# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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# THE SOFTWARE.
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CHARSET = 'qpzry9x8gf2tvdw0s3jn54khce6mua7l'
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def cashaddr_polymod(values):
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generator = [0x98f2bc8e61, 0x79b76d99e2, 0xf33e5fb3c4, 0xae2eabe2a8, 0x1e4f43e470]
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chk = 1
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for value in values:
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top = chk >> 35
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chk = ((chk & 0x07ffffffff) << 5) ^ value
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for i in range(5):
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chk ^= generator[i] if (top & (1 << i)) else 0
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return chk ^ 1
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def prefix_expand(prefix):
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return [ord(x) & 0x1f for x in prefix] + [0]
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def calculate_checksum(prefix, payload):
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poly = cashaddr_polymod(prefix_expand(prefix) + payload + [0, 0, 0, 0, 0, 0, 0, 0])
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out = list()
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for i in range(8):
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out.append((poly >> 5 * (7 - i)) & 0x1f)
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return out
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def verify_checksum(prefix, payload):
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return cashaddr_polymod(prefix_expand(prefix) + payload) == 0
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def b32decode(inputs):
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out = list()
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for letter in inputs:
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out.append(CHARSET.find(letter))
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return out
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def b32encode(inputs):
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out = ''
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for char_code in inputs:
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out += CHARSET[char_code]
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return out
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def convertbits(data, frombits, tobits, pad=True):
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acc = 0
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bits = 0
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ret = []
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maxv = (1 << tobits) - 1
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max_acc = (1 << (frombits + tobits - 1)) - 1
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for value in data:
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if value < 0 or (value >> frombits):
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return None
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acc = ((acc << frombits) | value) & max_acc
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bits += frombits
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while bits >= tobits:
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bits -= tobits
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ret.append((acc >> bits) & maxv)
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if pad:
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if bits:
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ret.append((acc << (tobits - bits)) & maxv)
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elif bits >= frombits or ((acc << (tobits - bits)) & maxv):
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return None
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return ret
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def encode(prefix, version, payload):
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payload = bytes([version]) + payload
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payload = convertbits(payload, 8, 5)
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checksum = calculate_checksum(prefix, payload)
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return prefix + ':' + b32encode(payload + checksum)
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def decode(prefix, addr):
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addr = addr.lower()
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decoded = b32decode(addr)
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if not verify_checksum(prefix, decoded):
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raise ValueError('Bad cashaddr checksum')
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data = bytes(convertbits(decoded, 5, 8))
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return data[0], data[1:-6]
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