diff --git a/setup.py b/setup.py
index a026bc1..fadf6ff 100644
--- a/setup.py
+++ b/setup.py
@@ -10,7 +10,7 @@ setup(
     url='http://github.com/romanz/trezor-agent',
     packages=['trezor_agent', 'trezor_agent.gpg'],
     scripts=['trezor_agent/gpg/trezor-git-gpg-wrapper.sh'],
-    install_requires=['ecdsa>=0.13', 'ed25519>=1.4', 'Cython>=0.23.4', 'trezor>=0.6.6', 'keepkey>=0.7.0', 'semver>=2.2'],
+    install_requires=['ecdsa>=0.13', 'ed25519>=1.4', 'Cython>=0.23.4', 'protobuf>=3.0.0b2.post2', 'trezor>=0.6.12', 'semver>=2.2'],
     platforms=['POSIX'],
     classifiers=[
         'Environment :: Console',
diff --git a/trezor_agent/__main__.py b/trezor_agent/__main__.py
index e6ad721..2926fc5 100644
--- a/trezor_agent/__main__.py
+++ b/trezor_agent/__main__.py
@@ -31,7 +31,7 @@ def create_parser():
     p = argparse.ArgumentParser()
     p.add_argument('-v', '--verbose', default=0, action='count')
 
-    curve_names = [name.decode('ascii') for name in formats.SUPPORTED_CURVES]
+    curve_names = [name for name in formats.SUPPORTED_CURVES]
     curve_names = ', '.join(sorted(curve_names))
     p.add_argument('-e', '--ecdsa-curve-name', metavar='CURVE',
                    default=formats.CURVE_NIST256,
@@ -128,7 +128,7 @@ def run_agent(client_factory=client.Client):
     args = create_agent_parser().parse_args()
     setup_logging(verbosity=args.verbose)
 
-    with client_factory(curve=args.ecdsa_curve_name.encode('ascii')) as conn:
+    with client_factory(curve=args.ecdsa_curve_name) as conn:
         label = args.identity
         command = args.command
 
@@ -156,7 +156,7 @@ def run_git(client_factory=client.Client):
     args = create_git_parser().parse_args()
     setup_logging(verbosity=args.verbose)
 
-    with client_factory(curve=args.ecdsa_curve_name.encode('ascii')) as conn:
+    with client_factory(curve=args.ecdsa_curve_name) as conn:
         label = git_host(args.remote, ['pushurl', 'url'])
         if not label:
             log.error('Could not find "%s" SSH remote in .git/config',
diff --git a/trezor_agent/formats.py b/trezor_agent/formats.py
index baa8ddd..de8ec82 100644
--- a/trezor_agent/formats.py
+++ b/trezor_agent/formats.py
@@ -12,8 +12,8 @@ from . import util
 log = logging.getLogger(__name__)
 
 # Supported ECDSA curves
-CURVE_NIST256 = b'nist256p1'
-CURVE_ED25519 = b'ed25519'
+CURVE_NIST256 = 'nist256p1'
+CURVE_ED25519 = 'ed25519'
 SUPPORTED_CURVES = {CURVE_NIST256, CURVE_ED25519}
 
 # SSH key types
diff --git a/trezor_agent/tests/test_client.py b/trezor_agent/tests/test_client.py
index b635b8e..7b9abd6 100644
--- a/trezor_agent/tests/test_client.py
+++ b/trezor_agent/tests/test_client.py
@@ -29,7 +29,7 @@ class FakeConnection(object):
     def get_public_node(self, n, ecdsa_curve_name=b'secp256k1'):
         assert not self.closed
         assert n == ADDR
-        assert ecdsa_curve_name in {b'secp256k1', b'nist256p1'}
+        assert ecdsa_curve_name in {'secp256k1', 'nist256p1'}
         result = mock.Mock(spec=[])
         result.node = mock.Mock(spec=[])
         result.node.public_key = PUBKEY
@@ -91,7 +91,7 @@ def test_ssh_agent():
                     client.identity_to_string(ident))
             assert challenge_hidden == BLOB
             assert challenge_visual == 'VISUAL'
-            assert ecdsa_curve_name == b'nist256p1'
+            assert ecdsa_curve_name == 'nist256p1'
 
             result = mock.Mock(spec=[])
             result.public_key = PUBKEY
diff --git a/trezor_agent/tests/test_formats.py b/trezor_agent/tests/test_formats.py
index ba28900..77a0491 100644
--- a/trezor_agent/tests/test_formats.py
+++ b/trezor_agent/tests/test_formats.py
@@ -29,7 +29,7 @@ def test_parse_public_key():
     assert key['name'] == b'home'
     assert key['point'] == _point
 
-    assert key['curve'] == b'nist256p1'
+    assert key['curve'] == 'nist256p1'
     assert key['fingerprint'] == '4b:19:bc:0f:c8:7e:dc:fa:1a:e3:c2:ff:6f:e0:80:a2'  # nopep8
     assert key['type'] == b'ecdsa-sha2-nistp256'
 
@@ -46,7 +46,7 @@ def test_parse_ed25519():
               'fSO8nLIi736is+f0erq28RTc7CkM11NZtTKR hello\n')
     p = formats.import_public_key(pubkey)
     assert p['name'] == b'hello'
-    assert p['curve'] == b'ed25519'
+    assert p['curve'] == 'ed25519'
 
     BLOB = (b'\x00\x00\x00\x0bssh-ed25519\x00\x00\x00 P]\x17kc}#'
             b'\xbc\x9c\xb2"\xef~\xa2\xb3\xe7\xf4z\xba\xb6\xf1\x14'