diff --git a/CHANGELOG.md b/CHANGELOG.md
index f512718..a1ef17b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,10 @@
 # @digitalbazaar/http-digest-header Changelog
 
+## 2.2.1 - 2025-10-dd
+
+### Fixed
+- Prevent making an unnecessary copy when encoding bytes.
+
 ## 2.2.0 - 2025-10-08
 
 ### Changed
diff --git a/lib/util.js b/lib/util.js
index c524a16..fb43b54 100644
--- a/lib/util.js
+++ b/lib/util.js
@@ -2,9 +2,11 @@
  * Copyright (c) 2021-2025 Digital Bazaar, Inc. All rights reserved.
  */
 export function base64Encode(bytes) {
-  return Buffer.from(bytes).toString('base64');
+  return Buffer.from(bytes.buffer, bytes.offset, bytes.length)
+    .toString('base64');
 }
 
 export function base64urlEncode(bytes) {
-  return Buffer.from(bytes).toString('base64url');
+  return Buffer.from(bytes.buffer, bytes.offset, bytes.length)
+    .toString('base64url');
 }