serializer: force serialization as array (iqlusioninc#546)

The implementation of array deserializer expects the payload to be
serialized as array. Sadly the serializer left the door open for the
underlying serializer to choice either bytes or array, if available.

This would only occur when the objects are used outside yubihsm.rs.

This change was tested on both mockhsm and yubihsm on usb.
rsa: when wrapped, the private does not carry the modulus

src/wrap/message.rs

@@ -149,10 +149,10 @@ impl Plaintext {
 
     /// Return the rsa key of this [`Plaintext`] if it was an RSA key.
     pub fn rsa(&self) -> Option<RsaPrivateKey> {
-        let (component_size, modulus_size) = match self.object_info.algorithm {
-            algorithm::Algorithm::Asymmetric(asymmetric::Algorithm::Rsa2048) => (128, 256),
-            algorithm::Algorithm::Asymmetric(asymmetric::Algorithm::Rsa3072) => (192, 384),
-            algorithm::Algorithm::Asymmetric(asymmetric::Algorithm::Rsa4096) => (256, 512),
+        let component_size = match self.object_info.algorithm {
+            algorithm::Algorithm::Asymmetric(asymmetric::Algorithm::Rsa2048) => 128,
+            algorithm::Algorithm::Asymmetric(asymmetric::Algorithm::Rsa3072) => 192,
+            algorithm::Algorithm::Asymmetric(asymmetric::Algorithm::Rsa4096) => 256,
             _ => return None,
         };
 
@@ -163,7 +163,6 @@ impl Plaintext {
         let _dp = BigUint::from_bytes_be(reader.read(component_size)?);
         let _dq = BigUint::from_bytes_be(reader.read(component_size)?);
         let _qinv = BigUint::from_bytes_be(reader.read(component_size)?);
-        let _n = BigUint::from_bytes_be(reader.read(modulus_size)?);
         const EXP: u64 = 65537;
         let e = BigUint::from_u64(EXP).expect("invalid static exponent");