diff --git a/libagent/device/trezor.py b/libagent/device/trezor.py
index 50ace4a..7b57207 100644
--- a/libagent/device/trezor.py
+++ b/libagent/device/trezor.py
@@ -89,7 +89,7 @@ class Trezor(interface.Device):
         """Return public key."""
         curve_name = identity.get_curve_name(ecdh=ecdh)
         log.debug('"%s" getting public key (%s) from %s',
-                  identity, curve_name, self)
+                  identity.to_string(), curve_name, self)
         addr = identity.get_bip32_address(ecdh=ecdh)
         result = self.conn.get_public_node(n=addr,
                                            ecdsa_curve_name=curve_name)
@@ -106,7 +106,7 @@ class Trezor(interface.Device):
         """Sign given blob and return the signature (as bytes)."""
         curve_name = identity.get_curve_name(ecdh=False)
         log.debug('"%s" signing %r (%s) on %s',
-                  identity, blob, curve_name, self)
+                  identity.to_string(), blob, curve_name, self)
         try:
             result = self.conn.sign_identity(
                 identity=self._identity_proto(identity),
@@ -126,7 +126,7 @@ class Trezor(interface.Device):
         """Get shared session key using Elliptic Curve Diffie-Hellman."""
         curve_name = identity.get_curve_name(ecdh=True)
         log.debug('"%s" shared session key (%s) for %r from %s',
-                  identity, curve_name, pubkey, self)
+                  identity.to_string(), curve_name, pubkey, self)
         try:
             result = self.conn.get_ecdh_session_key(
                 identity=self._identity_proto(identity),
diff --git a/libagent/gpg/client.py b/libagent/gpg/client.py
index 1d20fb3..01ef46a 100644
--- a/libagent/gpg/client.py
+++ b/libagent/gpg/client.py
@@ -32,7 +32,7 @@ class Client(object):
     def sign(self, identity, digest):
         """Sign the digest and return a serialized signature."""
         log.info('please confirm GPG signature on %s for "%s"...',
-                 self.device, identity)
+                 self.device, identity.to_string())
         if identity.curve_name == formats.CURVE_NIST256:
             digest = digest[:32]  # sign the first 256 bits
         log.debug('signing digest: %s', util.hexlify(digest))
@@ -43,6 +43,6 @@ class Client(object):
     def ecdh(self, identity, pubkey):
         """Derive shared secret using ECDH from remote public key."""
         log.info('please confirm GPG decryption on %s for "%s"...',
-                 self.device, identity)
+                 self.device, identity.to_string())
         with self.device:
             return self.device.ecdh(pubkey=pubkey, identity=identity)