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signer: refactor a bit

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This commit is contained in:
Roman Zeyde
2016-04-18 22:10:00 +03:00
parent b2d078eec6
commit 96592269b6
1 changed files with 25 additions and 21 deletions
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46
gpg/signer.py
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@@ -9,8 +9,6 @@ import struct
import subprocess
import time
import ecdsa
import decode
import trezor_agent.client
import trezor_agent.formats
@@ -75,18 +73,18 @@ def hexlify(blob):
class Signer(object):
curve = ecdsa.NIST256p
ecdsa_curve_name = trezor_agent.formats.CURVE_NIST256
def __init__(self, user_id, created):
self.user_id = user_id
self.client_wrapper = trezor_agent.factory.load()
# This requires the following patch to trezor-mcu to work:
# This requires the following patch to trezor-mcu in order to work:
# https://gist.github.com/romanz/b66f5df1ca8ef15641df8ea5bb09fd47
self.identity = self.client_wrapper.identity_type()
self.identity.proto = 'gpg'
self.identity.host = user_id
addr = trezor_agent.client.get_address(self.identity)
public_node = self.client_wrapper.connection.get_public_node(
n=addr, ecdsa_curve_name=self.ecdsa_curve_name)
@@ -96,36 +94,41 @@ class Signer(object):
curve_name=self.ecdsa_curve_name)
self.created = int(created)
self.pubkey_point = verifying_key.pubkey.point
log.info('key %s created at %s',
hexlify(self._fingerprint()[-4:]), time_format(self.created))
def _pubkey_data(self):
header = struct.pack('>BLB',
4, # version
self.created, # creation
19) # ECDSA
# https://tools.ietf.org/html/rfc6637#section-11 (NIST P-256 OID)
oid = prefix_len('>B', b'\x2A\x86\x48\xCE\x3D\x03\x01\x07')
return header + oid + mpi((4 << 512) |
(self.pubkey_point.x() << 256) |
(self.pubkey_point.y()))
self._point = verifying_key.pubkey.point
self.pubkey_data = header + oid + mpi((4 << 512) |
(self._point.x() << 256) |
(self._point.y()))
def _pubkey_data_to_hash(self):
return b'\x99' + prefix_len('>H', self._pubkey_data())
self.data_to_hash = b'\x99' + prefix_len('>H', self.pubkey_data)
fingerprint = hashlib.sha1(self.data_to_hash).digest()
self.key_id = fingerprint[-8:]
log.info('key %s created at %s',
hexlify(fingerprint[-4:]), time_format(self.created))
def _fingerprint(self):
return hashlib.sha1(self._pubkey_data_to_hash()).digest()
def key_id(self):
return self._fingerprint()[-8:]
def close(self):
self.client_wrapper.connection.clear_session()
self.client_wrapper.connection.close()
def export(self):
pubkey_packet = packet(tag=6, blob=self.pubkey_data)
pubkey_packet = packet(tag=6, blob=self._pubkey_data())
user_id_packet = packet(tag=13, blob=self.user_id)
user_id_to_hash = user_id_packet[:1] + prefix_len('>L', self.user_id)
data_to_sign = self.data_to_hash + user_id_to_hash
key_id = hexlify(self.key_id[-4:])
data_to_sign = self._pubkey_data_to_hash() + user_id_to_hash
key_id = hexlify(self.key_id()[-4:])
log.info('signing public key "%s": %s', self.user_id, key_id)
hashed_subpackets = [
subpacket_time(self.created), # signature creaion time
@@ -148,7 +151,7 @@ class Signer(object):
log.info('signing message %r at %s', msg,
time_format(sign_time))
hashed_subpackets = [subpacket_time(sign_time)]
key_id = hexlify(self.key_id[-4:])
key_id = hexlify(self.key_id()[-4:])
blob = self._make_signature(
visual=key_id,
data_to_sign=msg, hashed_subpackets=hashed_subpackets)
@@ -163,7 +166,7 @@ class Signer(object):
8) # hash_alg (SHA256)
hashed = subpackets(*hashed_subpackets)
unhashed = subpackets(
subpacket(16, self.key_id) # issuer key id
subpacket(16, self.key_id()) # issuer key id
)
tail = b'\x04\xff' + struct.pack('>L', len(header) + len(hashed))
data_to_hash = data_to_sign + header + hashed + tail
@@ -180,7 +183,8 @@ class Signer(object):
sig = result.signature[1:]
sig = [trezor_agent.util.bytes2num(sig[:32]),
trezor_agent.util.bytes2num(sig[32:])]
decode.verify_digest(pubkey={'point': (self._point.x(), self._point.y())},
decode.verify_digest(pubkey={'point': (self.pubkey_point.x(),
self.pubkey_point.y())},
digest=digest,
signature=sig, label='GPG signature')
@@ -233,7 +237,7 @@ def main():
else:
pubkey = load_from_gpg(args.user_id)
s = Signer(user_id=user_id, created=pubkey['created'])
assert s.key_id == pubkey['key_id']
assert s.key_id() == pubkey['key_id']
data = open(args.filename, 'rb').read()
sig, ext = s.sign(data), '.sig'