Minor cleanups

src/key.rs

@@ -422,7 +422,6 @@ pub fn generate(
     pin_policy: PinPolicy,
     touch_policy: TouchPolicy,
 ) -> Result<GeneratedKey, Error> {
-    let mut templ = [0, Ins::GenerateAsymmetric.code(), 0, 0];
     let setting_roca: settings::BoolValue;
 
     match algorithm {
@@ -470,7 +469,7 @@ pub fn generate(
 
     let txn = yubikey.begin_transaction()?;
 
-    templ[3] = slot.into();
+    let templ = [0, Ins::GenerateAsymmetric.code(), 0, slot.into()];
 
     let mut in_data = [0u8; 11];
     in_data[0] = 0xac;
@@ -512,7 +511,7 @@ pub fn generate(
                 return Err(Error::AuthenticationError);
             }
             other => {
-                error!("{} (error {:x})", err_msg, other.code());
+                error!("{} (error {:?})", err_msg, other);
                 return Err(Error::GenericError);
             }
         }

src/yubikey.rs

@@ -227,10 +227,12 @@ impl YubiKey {
     pub fn authenticate(&mut self, mgm_key: MgmKey) -> Result<(), Error> {
         let txn = self.begin_transaction()?;
 
+        const TAG_DYN_AUTH: u8 = 0x7c;
+
         // get a challenge from the card
         let challenge = APDU::new(Ins::Authenticate)
             .params(YKPIV_ALGO_3DES, YKPIV_KEY_CARDMGM)
-            .data(&[0x7c, 0x02, 0x80, 0x00])
+            .data(&[TAG_DYN_AUTH, 0x02, 0x80, 0x00])
             .transmit(&txn, 261)?;
 
         if !challenge.is_success() || challenge.data().len() < 12 {
@@ -241,7 +243,7 @@ impl YubiKey {
         let response = mgm_key.decrypt(challenge.data()[4..12].try_into().unwrap());
 
         let mut data = [0u8; 22];
-        data[0] = 0x7c;
+        data[0] = TAG_DYN_AUTH;
         data[1] = 20; // 2 + 8 + 2 +8
         data[2] = 0x80;
         data[3] = 8;