diff --git a/random.c b/random.c
index e5a61a8..f58740e 100644
--- a/random.c
+++ b/random.c
@@ -56,7 +56,7 @@ static void refill(struct random_state *state) {
 
 u16 get_random_u16(struct random_state *state) {
     u16 value;
-    size_t remaining = RANDOM_CACHE_SIZE - state->index;
+    unsigned remaining = RANDOM_CACHE_SIZE - state->index;
     if (remaining < sizeof(value)) {
         refill(state);
     }
@@ -83,7 +83,7 @@ u16 get_random_u16_uniform(struct random_state *state, u16 bound) {
 
 u64 get_random_u64(struct random_state *state) {
     u64 value;
-    size_t remaining = RANDOM_CACHE_SIZE - state->index;
+    unsigned remaining = RANDOM_CACHE_SIZE - state->index;
     if (remaining < sizeof(value)) {
         refill(state);
     }
diff --git a/random.h b/random.h
index 30672d4..420797d 100644
--- a/random.h
+++ b/random.h
@@ -4,12 +4,12 @@
 #include "chacha.h"
 #include "util.h"
 
-#define RANDOM_CACHE_SIZE 256ULL
-#define RANDOM_RESEED_SIZE 256ULL * 1024
+#define RANDOM_CACHE_SIZE 256U
+#define RANDOM_RESEED_SIZE (256U * 1024)
 
 struct random_state {
-    size_t index;
-    size_t reseed;
+    unsigned index;
+    unsigned reseed;
     chacha_ctx ctx;
     u8 cache[RANDOM_CACHE_SIZE];
 };