diff --git a/tests/pico-fido/test_blob.py b/tests/pico-fido/test_blob.py
new file mode 100644
index 0000000..7458fb7
--- /dev/null
+++ b/tests/pico-fido/test_blob.py
@@ -0,0 +1,69 @@
+import pytest
+from fido2.ctap import CtapError
+from fido2.ctap2.pin import PinProtocolV2, ClientPin
+from utils import verify
+import os
+
+PIN='12345678'
+SMALL_BLOB=b"A"*32
+
+@pytest.fixture(scope="function")
+def MCCredBlob(device):
+    res = device.doMC(extensions={'credBlob': SMALL_BLOB})['res'].attestation_object
+    return res
+
+@pytest.fixture(scope="function")
+def GACredBlob(device, MCCredBlob):
+    res = device.doGA(allow_list=[
+            {"id": MCCredBlob.auth_data.credential_data.credential_id, "type": "public-key"}
+        ], extensions={'getCredBlob': True})
+
+    assertions = res['res'].get_assertions()
+    for a in assertions:
+        verify(MCCredBlob, a, res['req']['client_data'].hash)
+    return assertions[0]
+
+def test_supports_credblob(info):
+    assert info.extensions
+    assert 'credBlob' in info.extensions
+    assert info.max_cred_blob_length
+    assert info.max_cred_blob_length > 0
+
+def test_mc_credblob(MCCredBlob):
+    assert MCCredBlob.auth_data.extensions
+    assert "credBlob" in MCCredBlob.auth_data.extensions
+    assert MCCredBlob.auth_data.extensions['credBlob'] is True
+
+def test_ga_credblob(GACredBlob):
+    assert GACredBlob.auth_data.extensions
+    assert "credBlob" in GACredBlob.auth_data.extensions
+    assert GACredBlob.auth_data.extensions['credBlob'] == SMALL_BLOB
+
+def test_wrong_credblob(device, info):
+    device.reset()
+    cdh = os.urandom(32)
+    ClientPin(device.client()._backend.ctap2).set_pin(PIN)
+    pin_token = ClientPin(device.client()._backend.ctap2).get_pin_token(PIN, permissions=ClientPin.PERMISSION.MAKE_CREDENTIAL | ClientPin.PERMISSION.AUTHENTICATOR_CFG)
+    protocol = PinProtocolV2()
+    MC = device.MC(
+        client_data_hash=cdh,
+        extensions={'credBlob': b'A'*(info.max_cred_blob_length+1)},
+        pin_uv_protocol=protocol.VERSION,
+        pin_uv_param=protocol.authenticate(pin_token, cdh)
+        )['res']
+
+    assert MC.auth_data.extensions
+    assert "credBlob" in MC.auth_data.extensions
+    assert MC.auth_data.extensions['credBlob'] is False
+
+    res = device.doGA(allow_list=[
+            {"id": MC.auth_data.credential_data.credential_id, "type": "public-key"}
+        ], extensions={'getCredBlob': True})
+
+    assertions = res['res'].get_assertions()
+    for a in assertions:
+        verify(MC, a, res['req']['client_data'].hash)
+
+    assert assertions[0].auth_data.extensions
+    assert "credBlob" in assertions[0].auth_data.extensions
+    assert len(assertions[0].auth_data.extensions['credBlob']) == 0