device: allow loading identities from a file (instead of argument)

trezor_agent/device/interface.py

@@ -45,20 +45,6 @@ def identity_to_string(identity_dict):
     return ''.join(result)
 
 
-def get_bip32_address(identity_dict, ecdh=False):
-    """Compute BIP32 derivation address according to SLIP-0013/0017."""
-    index = struct.pack('<L', identity_dict.get('index', 0))
-    addr = index + identity_to_string(identity_dict).encode('ascii')
-    log.debug('bip32 address string: %r', addr)
-    digest = hashlib.sha256(addr).digest()
-    s = io.BytesIO(bytearray(digest))
-
-    hardened = 0x80000000
-    addr_0 = [13, 17][bool(ecdh)]
-    address_n = [addr_0] + list(util.recv(s, '<LLLL'))
-    return [(hardened | value) for value in address_n]
-
-
 class Error(Exception):
     """Device-related error."""
 
@@ -71,18 +57,49 @@ class DeviceError(Error):
     """"Error during device operation."""
 
 
-class Device(object):
-    """Abstract cryptographic hardware device interface."""
+class Identity(object):
+    """Represent SLIP-0013 identity, together with a elliptic curve choice."""
 
     def __init__(self, identity_str, curve_name):
         """Configure for specific identity and elliptic curve usage."""
         self.identity_dict = string_to_identity(identity_str)
         self.curve_name = curve_name
-        self.conn = None
 
-    def identity_str(self):
+    def items(self):
+        """Return a copy of identity_dict items."""
+        return self.identity_dict.items()
+
+    def __str__(self):
         """Return identity serialized to string."""
-        return identity_to_string(self.identity_dict)
+        return '<{}|{}>'.format(identity_to_string(self.identity_dict), self.curve_name)
+
+    def get_bip32_address(self, ecdh=False):
+        """Compute BIP32 derivation address according to SLIP-0013/0017."""
+        index = struct.pack('<L', self.identity_dict.get('index', 0))
+        addr = index + identity_to_string(self.identity_dict).encode('ascii')
+        log.debug('bip32 address string: %r', addr)
+        digest = hashlib.sha256(addr).digest()
+        s = io.BytesIO(bytearray(digest))
+
+        hardened = 0x80000000
+        addr_0 = [13, 17][bool(ecdh)]
+        address_n = [addr_0] + list(util.recv(s, '<LLLL'))
+        return [(hardened | value) for value in address_n]
+
+    def get_curve_name(self, ecdh=False):
+        """Return correct curve name for device operations."""
+        if ecdh:
+            return formats.get_ecdh_curve_name(self.curve_name)
+        else:
+            return self.curve_name
+
+
+class Device(object):
+    """Abstract cryptographic hardware device interface."""
+
+    def __init__(self):
+        """C-tor."""
+        self.conn = None
 
     def connect(self):
         """Connect to device, otherwise raise NotFoundError."""
@@ -101,25 +118,18 @@ class Device(object):
             log.exception('close failed: %s', e)
         self.conn = None
 
-    def pubkey(self, ecdh=False):
+    def pubkey(self, identity, ecdh=False):
         """Get public key (as bytes)."""
         raise NotImplementedError()
 
-    def sign(self, blob):
+    def sign(self, identity, blob):
         """Sign given blob and return the signature (as bytes)."""
         raise NotImplementedError()
 
-    def ecdh(self, pubkey):
+    def ecdh(self, identity, pubkey):
         """Get shared session key using Elliptic Curve Diffie-Hellman."""
         raise NotImplementedError()
 
     def __str__(self):
         """Human-readable representation."""
         return '{}'.format(self.__class__.__name__)
-
-    def get_curve_name(self, ecdh=False):
-        """Return correct curve name for device operations."""
-        if ecdh:
-            return formats.get_ecdh_curve_name(self.curve_name)
-        else:
-            return self.curve_name