diff --git a/openpgp-card-sequoia/src/lib.rs b/openpgp-card-sequoia/src/lib.rs
index 1dab6e2..a13f239 100644
--- a/openpgp-card-sequoia/src/lib.rs
+++ b/openpgp-card-sequoia/src/lib.rs
@@ -172,6 +172,7 @@ pub fn public_key_material_to_key(
                 panic!("unexpected algo {:?}", algo);
             }
         }
+        _ => unimplemented!("Unexpected PublicKeyMaterial type"),
     }
 }
 
diff --git a/openpgp-card/src/crypto_data.rs b/openpgp-card/src/crypto_data.rs
index 4b2d3bd..793adc3 100644
--- a/openpgp-card/src/crypto_data.rs
+++ b/openpgp-card/src/crypto_data.rs
@@ -12,6 +12,7 @@ use crate::card_do::{Fingerprint, KeyGenerationTime};
 use crate::errors::OpenpgpCardError;
 
 /// A hash value that can be signed by the card.
+#[non_exhaustive]
 pub enum Hash<'a> {
     SHA256([u8; 0x20]),
     SHA384([u8; 0x30]),
@@ -49,6 +50,7 @@ impl Hash<'_> {
 }
 
 /// Data that can be decrypted on the card.
+#[non_exhaustive]
 pub enum Cryptogram<'a> {
     // message/ciphertext
     RSA(&'a [u8]),
@@ -74,6 +76,7 @@ pub trait CardUploadableKey {
 
 /// Algorithm-independent container for private key material to upload to
 /// an OpenPGP card
+#[non_exhaustive]
 pub enum PrivateKeyMaterial {
     R(Box<dyn RSAKey>),
     E(Box<dyn EccKey>),
@@ -99,6 +102,7 @@ pub trait EccKey {
 /// Algorithm-independent container for public key material retrieved from
 /// an OpenPGP card
 #[derive(Debug)]
+#[non_exhaustive]
 pub enum PublicKeyMaterial {
     R(RSAPub),
     E(EccPub),
@@ -106,6 +110,7 @@ pub enum PublicKeyMaterial {
 
 /// RSA-specific container for public key material from an OpenPGP card.
 #[derive(Debug)]
+#[non_exhaustive]
 pub struct RSAPub {
     /// Modulus (a number denoted as n coded on x bytes)
     n: Vec<u8>,
@@ -130,6 +135,7 @@ impl RSAPub {
 
 /// ECC-specific container for public key material from an OpenPGP card.
 #[derive(Debug)]
+#[non_exhaustive]
 pub struct EccPub {
     data: Vec<u8>,
     algo: Algo,
@@ -151,6 +157,7 @@ impl EccPub {
 /// A marker to distinguish between elliptic curve algorithms (ECDH, ECDSA,
 /// EdDSA)
 #[derive(PartialEq, Eq, Debug, Clone, Copy)]
+#[non_exhaustive]
 pub enum EccType {
     ECDH,
     ECDSA,
diff --git a/openpgp-card/src/errors.rs b/openpgp-card/src/errors.rs
index 34cb972..d699dd2 100644
--- a/openpgp-card/src/errors.rs
+++ b/openpgp-card/src/errors.rs
@@ -14,6 +14,7 @@ use thiserror::Error;
 
 /// Enum that wraps the different error types that this crate can return
 #[derive(Error, Debug)]
+#[non_exhaustive]
 pub enum OpenpgpCardError {
     #[error("Error interacting with smartcard: {0}")]
     Smartcard(SmartcardError),
@@ -45,6 +46,7 @@ impl From<anyhow::Error> for OpenpgpCardError {
 
 /// OpenPGP card "Status Byte" errors
 #[derive(Error, Debug, PartialEq)]
+#[non_exhaustive]
 pub enum OcErrorStatus {
     #[error("Selected file or DO in termination state")]
     TerminationState,
@@ -150,6 +152,7 @@ impl From<(u8, u8)> for OcErrorStatus {
 
 /// Errors on the smartcard/reader layer
 #[derive(Error, Debug)]
+#[non_exhaustive]
 pub enum SmartcardError {
     #[error("Failed to create a pcsc smartcard context {0}")]
     ContextError(String),