diff --git a/src/taoensso/nippy.clj b/src/taoensso/nippy.clj
index 8087936..322841a 100644
--- a/src/taoensso/nippy.clj
+++ b/src/taoensso/nippy.clj
@@ -1253,7 +1253,7 @@
 
 (def ^:private head-meta-id (reduce-kv #(assoc %1 %3 %2) {} head-meta))
 (def ^:private get-head-ba
-  (enc/memoize_
+  (enc/fmemoize
     (fn [head-meta]
       (when-let [meta-id (get head-meta-id (assoc head-meta :version head-version))]
         (enc/ba-concat head-sig (byte-array [meta-id]))))))
diff --git a/src/taoensso/nippy/encryption.clj b/src/taoensso/nippy/encryption.clj
index ce8ae4e..a4e4e32 100644
--- a/src/taoensso/nippy/encryption.clj
+++ b/src/taoensso/nippy/encryption.clj
@@ -103,7 +103,7 @@
   (AES128Encryptor. :aes128-gcm-sha512
     crypto/cipher-kit-aes-gcm
     (do           (fn [ salt-ba pwd] (crypto/take-ba 16 (crypto/sha512-key-ba salt-ba pwd (* Short/MAX_VALUE 5)))))
-    (enc/memoize_ (fn [_salt-ba pwd] (crypto/take-ba 16 (crypto/sha512-key-ba nil     pwd (* Short/MAX_VALUE 64)))))))
+    (enc/fmemoize (fn [_salt-ba pwd] (crypto/take-ba 16 (crypto/sha512-key-ba nil     pwd (* Short/MAX_VALUE 64)))))))
 
 (def aes128-cbc-encryptor
   "Default 128bit AES-CBC encryptor with many-round SHA-512 key-gen.
@@ -111,7 +111,7 @@
   (AES128Encryptor. :aes128-cbc-sha512
     crypto/cipher-kit-aes-cbc
     (do           (fn [ salt-ba pwd] (crypto/take-ba 16 (crypto/sha512-key-ba salt-ba pwd (* Short/MAX_VALUE 5)))))
-    (enc/memoize_ (fn [_salt-ba pwd] (crypto/take-ba 16 (crypto/sha512-key-ba nil     pwd (* Short/MAX_VALUE 64)))))))
+    (enc/fmemoize (fn [_salt-ba pwd] (crypto/take-ba 16 (crypto/sha512-key-ba nil     pwd (* Short/MAX_VALUE 64)))))))
 
 ;;;; Default implementation