diff --git a/shadowaead_2022/xor.go b/shadowaead_2022/xor.go
index 3e09591..007742f 100644
--- a/shadowaead_2022/xor.go
+++ b/shadowaead_2022/xor.go
@@ -1,7 +1,7 @@
+//go:build go1.20
+
 package shadowaead_2022
 
-import _ "unsafe"
+import "crypto/subtle"
 
-//go:linkname xorWords crypto/cipher.xorWords
-//go:noescape
-func xorWords(dst, a, b []byte)
+var xorWords = subtle.XORBytes
diff --git a/shadowaead_2022/xor_go119.go b/shadowaead_2022/xor_go119.go
new file mode 100644
index 0000000..35fb48c
--- /dev/null
+++ b/shadowaead_2022/xor_go119.go
@@ -0,0 +1,9 @@
+//go:build !go1.20
+
+package shadowaead_2022
+
+import _ "unsafe"
+
+//go:linkname xorWords crypto/cipher.xorWords
+//go:noescape
+func xorWords(dst, a, b []byte)