diff --git a/library/aesce.c b/library/aesce.c
index eaaa5b5..6a9e0a1 100644
--- a/library/aesce.c
+++ b/library/aesce.c
@@ -334,7 +334,7 @@
      *   - Section 5, Nr = Nk + 6
      *   - Section 5.2, the length of round keys is Nb*(Nr+1)
      */
-    const uint32_t key_len_in_words = key_bit_length / 32;  /* Nk */
+    const size_t key_len_in_words = key_bit_length / 32;    /* Nk */
     const size_t round_key_len_in_words = 4;                /* Nb */
     const size_t rounds_needed = key_len_in_words + 6;      /* Nr */
     const size_t round_keys_len_in_words =
diff --git a/library/lms.c b/library/lms.c
index 08fe753..8d3cae0 100644
--- a/library/lms.c
+++ b/library/lms.c
@@ -65,7 +65,8 @@
 #define H_TREE_HEIGHT_MAX                  10
 #define MERKLE_TREE_NODE_AM(type)          ((size_t) 1 << (MBEDTLS_LMS_H_TREE_HEIGHT(type) + 1u))
 #define MERKLE_TREE_LEAF_NODE_AM(type)     ((size_t) 1 << MBEDTLS_LMS_H_TREE_HEIGHT(type))
-#define MERKLE_TREE_INTERNAL_NODE_AM(type) ((size_t) 1 << MBEDTLS_LMS_H_TREE_HEIGHT(type))
+#define MERKLE_TREE_INTERNAL_NODE_AM(type) ((unsigned int) \
+                                            (1u << MBEDTLS_LMS_H_TREE_HEIGHT(type)))
 
 #define D_CONST_LEN           (2)
 static const unsigned char D_LEAF_CONSTANT_BYTES[D_CONST_LEN] = { 0x82, 0x82 };