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49 lines
1.7 KiB
Python
49 lines
1.7 KiB
Python
"""Device abstraction layer for GPG operations."""
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import logging
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from .. import formats, util
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from ..device import interface
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log = logging.getLogger(__name__)
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def create_identity(user_id, curve_name):
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"""Create GPG identity for hardware device."""
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result = interface.Identity(identity_str='gpg://', curve_name=curve_name)
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result.identity_dict['host'] = user_id
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return result
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class Client:
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"""Sign messages and get public keys from a hardware device."""
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def __init__(self, device):
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"""C-tor."""
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self.device = device
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def pubkey(self, identity, ecdh=False):
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"""Return public key as VerifyingKey object."""
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with self.device:
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pubkey = self.device.pubkey(ecdh=ecdh, identity=identity)
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return formats.decompress_pubkey(
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pubkey=pubkey, curve_name=identity.curve_name)
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def sign(self, identity, digest):
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"""Sign the digest and return a serialized signature."""
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log.info('please confirm GPG signature on %s for "%s"...',
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self.device, identity.to_string())
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if identity.curve_name == formats.CURVE_NIST256:
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digest = digest[:32] # sign the first 256 bits
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log.debug('signing digest: %s', util.hexlify(digest))
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with self.device:
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sig = self.device.sign(blob=digest, identity=identity)
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return (util.bytes2num(sig[:32]), util.bytes2num(sig[32:]))
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def ecdh(self, identity, pubkey):
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"""Derive shared secret using ECDH from remote public key."""
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log.info('please confirm GPG decryption on %s for "%s"...',
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self.device, identity.to_string())
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with self.device:
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return self.device.ecdh(pubkey=pubkey, identity=identity)
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