diff --git a/tox.ini b/tox.ini
index e9b50e3..9b2a98b 100644
--- a/tox.ini
+++ b/tox.ini
@@ -10,7 +10,7 @@ deps=
     semver
     pydocstyle
 commands=
-    pep8 trezor_agent
+    pep8 trezor_agent --max-line-length=100
     pylint --reports=no --rcfile .pylintrc trezor_agent
     pydocstyle trezor_agent
     coverage run --omit='trezor_agent/__main__.py' --source trezor_agent -m py.test -v trezor_agent
diff --git a/trezor_agent/gpg/decode.py b/trezor_agent/gpg/decode.py
index 1d771c6..8df20d7 100644
--- a/trezor_agent/gpg/decode.py
+++ b/trezor_agent/gpg/decode.py
@@ -320,7 +320,8 @@ def verify_digest(pubkey, digest, signature, label):
         raise
 
 
-def _remove_armor(armored_data):
+def remove_armor(armored_data):
+    """Decode armored data into its binary form."""
     stream = io.BytesIO(armored_data)
     lines = stream.readlines()[3:-1]
     data = base64.b64decode(b''.join(lines))
@@ -331,7 +332,7 @@ def _remove_armor(armored_data):
 
 def verify(pubkey, signature, original_data):
     """Verify correctness of public key and signature."""
-    stream = io.BytesIO(_remove_armor(signature))
+    stream = io.BytesIO(remove_armor(signature))
     signature, digest = load_signature(stream, original_data)
     verify_digest(pubkey=pubkey, digest=digest,
                   signature=signature['sig'], label='GPG signature')
diff --git a/trezor_agent/gpg/tests/test_decode.py b/trezor_agent/gpg/tests/test_decode.py
new file mode 100644
index 0000000..1958526
--- /dev/null
+++ b/trezor_agent/gpg/tests/test_decode.py
@@ -0,0 +1,59 @@
+import io
+
+from .. import decode
+from ... import util
+
+
+def test_subpackets():
+    s = io.BytesIO(b'\x00\x05\x02\xAB\xCD\x01\xEF')
+    assert decode.parse_subpackets(util.Reader(s)) == [b'\xAB\xCD', b'\xEF']
+
+
+def test_mpi():
+    s = io.BytesIO(b'\x00\x09\x01\x23')
+    assert decode.parse_mpi(util.Reader(s)) == 0x123
+
+
+def assert_subdict(d, s):
+    for k, v in s.items():
+        assert d[k] == v
+
+
+def test_primary_nist256p1():
+    # pylint: disable=line-too-long
+    data = b'''-----BEGIN PGP PUBLIC KEY BLOCK-----
+Version: GnuPG v2
+
+mFIEV0hI1hMIKoZIzj0DAQcCAwTXY7aq01xMPSU7gTHU9B7Z2CFoCk1Y4WYb8Tiy
+hurvIZ5la6+UEgAKF9HXpQo0yE+HQOgufoLlCpdE7NoEUb+HtAd0ZXN0aW5niHYE
+ExMIABIFAldISNYCGwMCFQgCFgACF4AAFgkQTcCehfpEIPILZFRSRVpPUi1HUEeV
+3QEApHKmBkbLVZNpsB8q9mBzKytxnOHNB3QWDuoKJu/ERi4A/1wRGZ/B0BDazHck
+zpR9luXTKwMEl+mlZmwEFKZXBmir
+=oyj0
+-----END PGP PUBLIC KEY BLOCK-----
+'''
+    stream = util.Reader(io.BytesIO(decode.remove_armor(data)))
+    pubkey, user_id, signature = list(decode.parse_packets(stream))
+    assert_subdict(pubkey, {
+        'created': 1464355030, 'type': 'pubkey', 'tag': 6,
+        'version': 4, 'algo': 19, 'key_id': b'M\xc0\x9e\x85\xfaD \xf2',
+        '_to_hash': b'\x99\x00R\x04WHH\xd6\x13\x08*\x86H\xce=\x03\x01\x07\x02\x03\x04\xd7c\xb6\xaa\xd3\\L=%;\x811\xd4\xf4\x1e\xd9\xd8!h\nMX\xe1f\x1b\xf18\xb2\x86\xea\xef!\x9eek\xaf\x94\x12\x00\n\x17\xd1\xd7\xa5\n4\xc8O\x87@\xe8.~\x82\xe5\n\x97D\xec\xda\x04Q\xbf\x87'  # nopep8
+    })
+    point = pubkey['verifying_key'].pubkey.point
+    assert point.x(), point.y() == (
+        97423441028100245505102979561460969898742433559010922791700160771755342491425,
+        71644624850142103522769833619875243486871666152651730678601507641225861250951
+    )
+    assert_subdict(user_id, {
+        'tag': 13, 'type': 'user_id', 'value': b'testing',
+        '_to_hash': b'\xb4\x00\x00\x00\x07testing'
+    })
+    assert_subdict(signature, {
+        'pubkey_alg': 19, '_is_custom': True, 'hash_alg': 8, 'tag': 2,
+        'sig_type': 19, 'version': 4, 'type': 'signature', 'hash_prefix': b'\x95\xdd',
+        'sig': (74381873592149178031432444136130575481350858387410643140628758456112511206958,
+                41642995320462795718437755373080464775445470754419831653624197847615308982443),
+        'hashed_subpackets': [b'\x02WHH\xd6', b'\x1b\x03', b'\x15\x08', b'\x16\x00', b'\x17\x80'],
+        'unhashed_subpackets': [b'\x10M\xc0\x9e\x85\xfaD \xf2', b'dTREZOR-GPG'],
+        '_to_hash': b'\x04\x13\x13\x08\x00\x12\x05\x02WHH\xd6\x02\x1b\x03\x02\x15\x08\x02\x16\x00\x02\x17\x80\x04\xff\x00\x00\x00\x18'  # nopep8
+    })