diff --git a/src/oath/hotp.rs b/src/oath/hotp.rs
index 20aef29..ced5504 100644
--- a/src/oath/hotp.rs
+++ b/src/oath/hotp.rs
@@ -180,7 +180,7 @@ impl OtpAuth for HOTPContext {
                 .ok_or_else(|| "Otpauth uri is malformed, missing parameters".to_string())
                 .and_then(|param_it| {
                     let mut secret = Vec::<u8>::new();
-                    let mut counter = std::u64::MAX;
+                    let mut counter = u64::MAX;
                     let mut alg = OTP_DEFAULT_ALG_VALUE;
                     let mut digits = OTP_DEFAULT_DIGITS_VALUE;
 
@@ -226,7 +226,7 @@ impl OtpAuth for HOTPContext {
                         }
                     }
 
-                    if secret.is_empty() || counter == std::u64::MAX {
+                    if secret.is_empty() || counter == u64::MAX {
                         return Err("Otpauth uri is malformed".to_string());
                     }
 
diff --git a/src/webauthn/authenticator/mod.rs b/src/webauthn/authenticator/mod.rs
index 3353de3..dd150b3 100644
--- a/src/webauthn/authenticator/mod.rs
+++ b/src/webauthn/authenticator/mod.rs
@@ -144,7 +144,11 @@ impl WebauthnAuthenticator {
         let (attestation_object, private_key_response, der) =
             Self::generate_attestation_object(alg, aaguid, &credential_id, rp_id, attestation_flags)?;
 
-        let challenge = base64::decode(credential_creation_options.challenge)?;
+        let challenge = match base64::decode(credential_creation_options.challenge.as_str()) {
+            Ok(challenge) => challenge,
+            Err(_) => base64::decode_config(credential_creation_options.challenge, URL_SAFE_NO_PAD)?,
+        };
+
         let collected_client_data = CollectedClientData {
             request_type: WEBAUTHN_REQUEST_TYPE_CREATE.to_owned(),
             challenge: base64::encode_config(challenge, URL_SAFE_NO_PAD),