diff --git a/src/lib/pubkey/hss_lms/hss.cpp b/src/lib/pubkey/hss_lms/hss.cpp
index 45da5fd5404..c31749e1e54 100644
--- a/src/lib/pubkey/hss_lms/hss.cpp
+++ b/src/lib/pubkey/hss_lms/hss.cpp
@@ -57,11 +57,12 @@ constexpr bool is_supported_hash_function(std::string_view hash_name) {
 std::vector<LMS_Tree_Node_Idx> derive_lms_leaf_indices_from_hss_index(HSS_Sig_Idx hss_idx,
                                                                       const HSS_LMS_Params& hss_params) {
    std::vector<LMS_Tree_Node_Idx> q(hss_params.L().get());
-   for(int8_t layer_ctr = hss_params.L().get() - 1; layer_ctr >= 0; --layer_ctr) {
+   for(int32_t layer_ctr = hss_params.L().get() - 1; layer_ctr >= 0; --layer_ctr) {
       HSS_Level layer(layer_ctr);
       const HSS_LMS_Params::LMS_LMOTS_Params_Pair& layer_params = hss_params.params_at_level(layer);
       size_t layer_h = layer_params.lms_params().h();
-      q.at(layer.get()) = LMS_Tree_Node_Idx(hss_idx.get() % (1UL << layer_h));
+      auto tmp = hss_idx.get();
+      q.at(layer.get()) = LMS_Tree_Node_Idx(static_cast<uint32_t>(hss_idx.get() % (1UL << layer_h)));
       hss_idx = hss_idx >> layer_h;
    }
    BOTAN_ARG_CHECK(hss_idx == HSS_Sig_Idx(0), "HSS Tree is exhausted");
diff --git a/src/lib/pubkey/hss_lms/hss.h b/src/lib/pubkey/hss_lms/hss.h
index 4d9799d0c15..cb511545f10 100644
--- a/src/lib/pubkey/hss_lms/hss.h
+++ b/src/lib/pubkey/hss_lms/hss.h
@@ -37,7 +37,7 @@ using HSS_Level = Strong<uint32_t, struct HSS_Level_, EnableArithmeticWithPlainN
  *
  * See RFC 8554 Section 6.
  */
-class HSS_LMS_Params final {
+class BOTAN_TEST_API HSS_LMS_Params final {
    public:
       /**
        * @brief Represents a pair of LMS and LMOTS parameters associated with one LMS tree layer.
@@ -99,7 +99,7 @@ class HSS_LMS_Params final {
       /**
        * @brief Returns the number of layers the HSS tree has.
        */
-      HSS_Level L() const { return static_cast<HSS_Level>(m_lms_lmots_params.size()); }
+      HSS_Level L() const { return HSS_Level(m_lms_lmots_params.size()); }
 
       /**
        * @brief The maximal number of signatures allowed for these HSS parameters
@@ -122,7 +122,7 @@ class HSS_LMS_Params final {
  * Note that the format is not specified in the RFC 8554,
  * and is Botan specific.
  */
-class HSS_LMS_PrivateKeyInternal final {
+class BOTAN_TEST_API HSS_LMS_PrivateKeyInternal final {
    public:
       /**
        * @brief Create an internal HSS-LMS private key.
@@ -239,7 +239,7 @@ class HSS_Signature;
  * Format according to RFC 8554:
  * u32str(L) || pub[0]
  */
-class HSS_LMS_PublicKeyInternal final {
+class BOTAN_TEST_API HSS_LMS_PublicKeyInternal final {
    public:
       /**
        * @brief Create the public HSS-LMS key from its private key.
@@ -318,7 +318,7 @@ class HSS_LMS_PublicKeyInternal final {
  * Format according to RFC 8554:
  * u32str(Nspk) || sig[0] || pub[1] || ... || sig[Nspk-1] || pub[Nspk] || sig[Nspk]
  */
-class HSS_Signature final {
+class BOTAN_TEST_API HSS_Signature final {
    public:
       /**
        * @brief A LMS public key signed by the HSS layer above it.
diff --git a/src/lib/pubkey/hss_lms/lm_ots.h b/src/lib/pubkey/hss_lms/lm_ots.h
index 4063fb7299d..7be3bf6d071 100644
--- a/src/lib/pubkey/hss_lms/lm_ots.h
+++ b/src/lib/pubkey/hss_lms/lm_ots.h
@@ -99,7 +99,7 @@ enum class LMOTS_Algorithm_Type : uint32_t {
  *
  * See RFC 8554 Section 4.1.
  */
-class LMOTS_Params {
+class BOTAN_TEST_API LMOTS_Params {
    public:
       /**
        * @brief Create the LM-OTS parameters from a known algorithm type.
@@ -172,7 +172,7 @@ class LMOTS_Params {
 /**
  * @brief Representation of a LM-OTS signature.
  */
-class LMOTS_Signature {
+class BOTAN_TEST_API LMOTS_Signature {
    public:
       /**
        * @brief Parse a LM-OTS signature.
@@ -216,7 +216,7 @@ class LMOTS_Signature {
  * @brief Base class for LMOTS private and public key. Contains the parameters for
  *        the specific OTS instance
  */
-class OTS_Instance {
+class BOTAN_TEST_API OTS_Instance {
    public:
       /**
        * @brief Constructor storing the specific OTS parameters
@@ -251,7 +251,7 @@ class OTS_Instance {
  * Contains the OTS params, I, q, the secret LMS seed and its derived
  * secret chain inputs (x[] in RFC 8554 4.2)
  */
-class LMOTS_Private_Key : public OTS_Instance {
+class BOTAN_TEST_API LMOTS_Private_Key : public OTS_Instance {
    public:
       /**
        * @brief Derive a LMOTS private key for a given @p seed.
@@ -300,7 +300,7 @@ class LMOTS_Private_Key : public OTS_Instance {
  *
  * u32str(type) || I || u32str(q) || K
  */
-class LMOTS_Public_Key : public OTS_Instance {
+class BOTAN_TEST_API LMOTS_Public_Key : public OTS_Instance {
    public:
       /**
        * @brief Derivivation of an LMOTS public key using an LMOTS_Private_Key as defined
diff --git a/src/lib/pubkey/hss_lms/lms.h b/src/lib/pubkey/hss_lms/lms.h
index 52c94f53a2a..31a875e6fe6 100644
--- a/src/lib/pubkey/hss_lms/lms.h
+++ b/src/lib/pubkey/hss_lms/lms.h
@@ -86,7 +86,7 @@ using LMS_Signature_Bytes = Strong<std::vector<uint8_t>, struct LMS_Signature_By
  *
  * See RFC 8554 Section 5.1.
  */
-class LMS_Params {
+class BOTAN_TEST_API LMS_Params {
    public:
       /**
        * @brief Create the LMS parameters from a known algorithm type.
@@ -143,7 +143,7 @@ class LMS_Params {
  * @brief Base class for LMS private and public key. Contains public data associated with this
  *        LMS instance.
  */
-class LMS_Instance {
+class BOTAN_TEST_API LMS_Instance {
    public:
       /**
        * @brief Constructor storing the provided LMS data.
@@ -182,7 +182,7 @@ class LMS_PublicKey;
  * Contains the secret seed used for OTS key derivation
  * as described in RFC 8554 Appendix A.
  */
-class LMS_PrivateKey : public LMS_Instance {
+class BOTAN_TEST_API LMS_PrivateKey : public LMS_Instance {
    public:
       /**
        * @brief Construct storing the LMS instance data and the secret seed
@@ -217,7 +217,7 @@ class LMS_Signature;
  * Format according to RFC 8554:
  * u32str(type) || u32str(otstype) || I || T[1]
  */
-class LMS_PublicKey : public LMS_Instance {
+class BOTAN_TEST_API LMS_PublicKey : public LMS_Instance {
    public:
       /**
        * @brief Parse a public LMS key.
@@ -283,7 +283,7 @@ class LMS_PublicKey : public LMS_Instance {
  *
  * Contains a method for secure signature parsing.
  */
-class LMS_Signature {
+class BOTAN_TEST_API LMS_Signature {
    public:
       /**
        * @brief Parse the bytes of a lms signature into a LMS Signature object