diff --git a/pass-webauthn/src/impls.rs b/pass-webauthn/src/impls.rs
new file mode 100644
index 0000000..a60baba
--- /dev/null
+++ b/pass-webauthn/src/impls.rs
@@ -0,0 +1,39 @@
+use frame_support::Parameter;
+use traits_authn::{Challenger, DeviceChallengeResponse, UserChallengeResponse};
+use verifier::webauthn_verify;
+
+use crate::{Assertions, Attestation};
+
+impl AsRef<[u8]> for Assertions {
+    fn as_ref(&self) -> &[u8] {
+        // See https://www.w3.org/TR/webauthn/#clientdatajson-serialization for more details
+        todo!("Concatenate assertions into the desired `authenticator_data`")
+    }
+}
+
+impl<Cx> DeviceChallengeResponse<Cx> for Attestation<Cx>
+where
+    Cx: Parameter + Copy + 'static,
+{
+    fn is_valid(&self) -> bool {
+        webauthn_verify(
+            self.authenticator_data.as_ref(),
+            &self.client_data,
+            &self.signature,
+            &self.public_key,
+        )
+        .is_ok()
+    }
+
+    fn used_challenge(&self) -> (Cx, traits_authn::Challenge) {
+        (self.context, self.authenticator_data.challenge)
+    }
+
+    fn authority(&self) -> traits_authn::AuthorityId {
+        self.rp_id
+    }
+
+    fn device_id(&self) -> &traits_authn::DeviceId {
+        todo!()
+    }
+}
diff --git a/pass-webauthn/src/lib.rs b/pass-webauthn/src/lib.rs
index 8731421..2eef0ca 100644
--- a/pass-webauthn/src/lib.rs
+++ b/pass-webauthn/src/lib.rs
@@ -1 +1,37 @@
 #![cfg_attr(not(feature = "std"), no_std)]
+
+use codec::{Decode, Encode};
+use frame_support::{DebugNoBound, Parameter};
+use scale_info::TypeInfo;
+use traits_authn::{AuthorityId, Challenge, Challenger};
+
+#[cfg(test)]
+mod tests;
+
+mod impls;
+
+type CxOf<Ch> = <Ch as Challenger>::Context;
+
+#[derive(Encode, Decode, TypeInfo, Debug, PartialEq, Eq, Clone)]
+pub struct Assertions {
+    challenge: Challenge,
+}
+
+#[derive(Encode, Decode, TypeInfo, DebugNoBound, PartialEq, Eq, Clone)]
+pub struct Attestation<Cx: Parameter> {
+    pub(crate) rp_id: AuthorityId,
+    pub(crate) context: Cx,
+    pub(crate) authenticator_data: Assertions,
+    pub(crate) client_data: Vec<u8>,
+    pub(crate) signature: Vec<u8>,
+    pub(crate) public_key: Vec<u8>,
+}
+
+#[derive(Encode, Decode)]
+pub struct Credential<Cx: Parameter> {
+    pub(crate) rp_id: AuthorityId,
+    pub(crate) context: Cx,
+    pub(crate) authenticator_data: Assertions,
+    pub(crate) client_data: Vec<u8>,
+    pub(crate) signature: Vec<u8>,
+}
diff --git a/pass-webauthn/src/tests.rs b/pass-webauthn/src/tests.rs
new file mode 100644
index 0000000..e69de29