diff --git a/src/atom.c b/src/atom.c
index fdcf73a94b..202a219597 100644
--- a/src/atom.c
+++ b/src/atom.c
@@ -14,14 +14,14 @@ struct atom_entry {
 };
 
 static inline int atom_getter(struct cache *cache attr_unused, const char *atom_name,
-                              struct cache_handle **value, void *user_data) {
+                              size_t keylen, struct cache_handle **value, void *user_data) {
 	xcb_connection_t *c = user_data;
 	xcb_intern_atom_reply_t *reply = xcb_intern_atom_reply(
-	    c, xcb_intern_atom(c, 0, to_u16_checked(strlen(atom_name)), atom_name), NULL);
+	    c, xcb_intern_atom(c, 0, to_u16_checked(keylen), atom_name), NULL);
 
 	xcb_atom_t atom = XCB_NONE;
 	if (reply) {
-		log_debug("Atom %s is %d", atom_name, reply->atom);
+		log_debug("Atom %.*s is %d", (int)keylen, atom_name, reply->atom);
 		atom = reply->atom;
 		free(reply);
 	} else {
@@ -41,17 +41,17 @@ atom_entry_free(struct cache *cache attr_unused, struct cache_handle *handle) {
 	free(entry);
 }
 
-xcb_atom_t get_atom(struct atom *a, const char *key, xcb_connection_t *c) {
+xcb_atom_t get_atom(struct atom *a, const char *key, size_t keylen, xcb_connection_t *c) {
 	struct cache_handle *entry = NULL;
-	if (cache_get_or_fetch(&a->c, key, &entry, c, atom_getter) < 0) {
+	if (cache_get_or_fetch(&a->c, key, keylen, &entry, c, atom_getter) < 0) {
 		log_error("Failed to get atom %s", key);
 		return XCB_NONE;
 	}
 	return cache_entry(entry, struct atom_entry, entry)->atom;
 }
 
-xcb_atom_t get_atom_cached(struct atom *a, const char *key) {
-	return cache_entry(cache_get(&a->c, key), struct atom_entry, entry)->atom;
+xcb_atom_t get_atom_cached(struct atom *a, const char *key, size_t keylen) {
+	return cache_entry(cache_get(&a->c, key, keylen), struct atom_entry, entry)->atom;
 }
 
 /**
@@ -60,7 +60,7 @@ xcb_atom_t get_atom_cached(struct atom *a, const char *key) {
 struct atom *init_atoms(xcb_connection_t *c) {
 	auto atoms = ccalloc(1, struct atom);
 	atoms->c = CACHE_INIT;
-#define ATOM_GET(x) atoms->a##x = get_atom(atoms, #x, c)
+#define ATOM_GET(x) atoms->a##x = get_atom(atoms, #x, sizeof(#x) - 1, c)
 	LIST_APPLY(ATOM_GET, SEP_COLON, ATOM_LIST1);
 	LIST_APPLY(ATOM_GET, SEP_COLON, ATOM_LIST2);
 #undef ATOM_GET
diff --git a/src/atom.h b/src/atom.h
index 0cebe3a090..a04739149c 100644
--- a/src/atom.h
+++ b/src/atom.h
@@ -62,7 +62,14 @@ struct atom {
 /// a reference to the connection.
 struct atom *init_atoms(xcb_connection_t *c);
 
-xcb_atom_t get_atom(struct atom *a, const char *key, xcb_connection_t *c);
-xcb_atom_t get_atom_cached(struct atom *a, const char *key);
+xcb_atom_t get_atom(struct atom *a, const char *key, size_t keylen, xcb_connection_t *c);
+static inline xcb_atom_t
+get_atom_with_nul(struct atom *a, const char *key, xcb_connection_t *c) {
+	return get_atom(a, key, strlen(key), c);
+}
+xcb_atom_t get_atom_cached(struct atom *a, const char *key, size_t keylen);
+static inline xcb_atom_t get_atom_cached_with_nul(struct atom *a, const char *key) {
+	return get_atom_cached(a, key, strlen(key));
+}
 
 void destroy_atoms(struct atom *a);
diff --git a/src/c2.c b/src/c2.c
index 0ca74148f7..37cd61f338 100644
--- a/src/c2.c
+++ b/src/c2.c
@@ -1151,7 +1151,7 @@ static bool c2_l_postprocess(struct c2_state *state, xcb_connection_t *c, c2_l_t
 
 	// Get target atom if it's not a predefined one
 	if (pleaf->predef == C2_L_PUNDEFINED) {
-		pleaf->tgtatom = get_atom(state->atoms, pleaf->tgt, c);
+		pleaf->tgtatom = get_atom_with_nul(state->atoms, pleaf->tgt, c);
 		if (!pleaf->tgtatom) {
 			log_error("Failed to get atom for target \"%s\".", pleaf->tgt);
 			return false;
diff --git a/src/cache.c b/src/cache.c
index e4f2927f70..bc67f5b6af 100644
--- a/src/cache.c
+++ b/src/cache.c
@@ -2,27 +2,29 @@
 
 #include "cache.h"
 
-struct cache_handle *cache_get(struct cache *c, const char *key) {
+struct cache_handle *cache_get(struct cache *c, const char *key, size_t keylen) {
 	struct cache_handle *e;
-	HASH_FIND_STR(c->entries, key, e);
+	HASH_FIND(hh, c->entries, key, keylen, e);
 	return e;
 }
 
-int cache_get_or_fetch(struct cache *c, const char *key, struct cache_handle **value,
-                       void *user_data, cache_getter_t getter) {
-	*value = cache_get(c, key);
+int cache_get_or_fetch(struct cache *c, const char *key, size_t keylen,
+                       struct cache_handle **value, void *user_data, cache_getter_t getter) {
+	*value = cache_get(c, key, keylen);
 	if (*value) {
 		return 0;
 	}
 
-	int err = getter(c, key, value, user_data);
+	int err = getter(c, key, keylen, value, user_data);
 	assert(err <= 0);
 	if (err < 0) {
 		return err;
 	}
-	(*value)->key = strdup(key);
+	// Add a NUL terminator to make things easier
+	(*value)->key = cvalloc(keylen + 1);
+	memcpy((*value)->key, key, keylen);
 
-	HASH_ADD_STR(c->entries, key, *value);
+	HASH_ADD_KEYPTR(hh, c->entries, (*value)->key, keylen, *value);
 	return 1;
 }
 
diff --git a/src/cache.h b/src/cache.h
index 8c022cf44a..c0fa8df240 100644
--- a/src/cache.h
+++ b/src/cache.h
@@ -12,7 +12,7 @@ struct cache_handle;
 /// Should return 0 if the value is fetched successfully, and a negative number if the
 /// value cannot be fetched. Getter doesn't need to initialize fields of `struct
 /// cache_handle`.
-typedef int (*cache_getter_t)(struct cache *, const char *key,
+typedef int (*cache_getter_t)(struct cache *, const char *key, size_t keylen,
                               struct cache_handle **value, void *user_data);
 typedef void (*cache_free_t)(struct cache *, struct cache_handle *value);
 
@@ -31,12 +31,12 @@ struct cache_handle {
 /// getter will be called, and the returned value will be stored into the cache.
 /// Returns 0 if the value is already present in the cache, 1 if the value is fetched
 /// successfully, and a negative number if the value cannot be fetched.
-int cache_get_or_fetch(struct cache *, const char *key, struct cache_handle **value,
-                       void *user_data, cache_getter_t getter);
+int cache_get_or_fetch(struct cache *, const char *key, size_t keylen,
+                       struct cache_handle **value, void *user_data, cache_getter_t getter);
 
 /// Get a value from the cache. If the value doesn't present in the cache, NULL will be
 /// returned.
-struct cache_handle *cache_get(struct cache *, const char *key);
+struct cache_handle *cache_get(struct cache *, const char *key, size_t keylen);
 
 /// Invalidate all values in the cache. After this call, `struct cache` holds no allocated
 /// memory, and can be discarded.
diff --git a/src/picom.c b/src/picom.c
index 7f5e8df4ed..0ff437efe8 100644
--- a/src/picom.c
+++ b/src/picom.c
@@ -1345,7 +1345,7 @@ static int register_cm(session_t *ps) {
 			log_fatal("Failed to allocate memory");
 			return -1;
 		}
-		atom = get_atom(ps->atoms, buf, ps->c.c);
+		atom = get_atom_with_nul(ps->atoms, buf, ps->c.c);
 		free(buf);
 
 		xcb_get_selection_owner_reply_t *reply = xcb_get_selection_owner_reply(