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trezor-firmware/tools/keyctl

72 lines
2.0 KiB
Python
Executable File

#!/usr/bin/env python3
import binascii
import struct
import click
import pyblake2
from trezorlib import ed25519raw, ed25519cosi
indexmap = {
'bootloader': 0,
'vendorheader': 1,
'firmware': 2,
}
def header_digest(index, filename):
data = open(filename, 'rb').read()
z = bytes(65 * [0x00])
if index == 'bootloader':
header = data[:0x03BF] + z
elif index == 'vendorheader':
header = data[:-65] + z
elif index == 'firmware':
vhdrlen = struct.unpack('<I', data[4:8])[0]
header = data[vhdrlen:vhdrlen + 0x03BF] + z
else:
raise ValueError('Unknown index "%s"' % index)
return pyblake2.blake2s(header).digest()
@click.group()
def cli():
pass
@cli.command(help='')
@click.argument('index', type=click.Choice(indexmap.keys()))
@click.argument('filename')
@click.argument('seckeys', nargs=-1)
def sign(index, filename, seckeys):
# compute header digest
digest = header_digest(index, filename)
# collect commits
pks, Rs = [], []
for ctr, seckey in enumerate(seckeys):
sk = binascii.unhexlify(seckey)
pk = ed25519raw.publickey(sk)
_, R = ed25519cosi.get_nonce(sk, digest, ctr)
pks.append(pk)
Rs.append(R)
# compute global commit
global_pk = ed25519cosi.combine_keys(pks)
global_R = ed25519cosi.combine_keys(Rs)
# collect signatures
sigs = []
for ctr, seckey in enumerate(seckeys):
sk = binascii.unhexlify(seckey)
r, _ = ed25519cosi.get_nonce(sk, digest, ctr)
h = ed25519raw.H(sk)
b = ed25519raw.b
a = 2 ** (b - 2) + sum(2 ** i * ed25519raw.bit(h, i) for i in range(3, b - 2))
S = (r + ed25519raw.Hint(global_R + global_pk + digest) * a) % ed25519raw.l
sig = ed25519raw.encodeint(S)
sigs.append(sig)
# compute global signature
sig = ed25519cosi.combine_sig(global_R, sigs)
ed25519raw.checkvalid(sig, digest, global_pk)
print(binascii.hexlify(sig).decode())
if __name__ == '__main__':
cli()