diff --git a/src/main/generated/Versions.java b/src/main/generated/Versions.java
index 3860dba..73f795a 100644
--- a/src/main/generated/Versions.java
+++ b/src/main/generated/Versions.java
@@ -30,6 +30,11 @@
  */
 @NullMarked
 public final class Versions {
+
+    private Versions() {
+        // Prevent instantiation
+    }
+
     /**
      * User agent value
      */
diff --git a/src/main/java/land/oras/LayoutRef.java b/src/main/java/land/oras/LayoutRef.java
index a3beca9..4bafc75 100644
--- a/src/main/java/land/oras/LayoutRef.java
+++ b/src/main/java/land/oras/LayoutRef.java
@@ -25,6 +25,7 @@
 import land.oras.exception.OrasException;
 import land.oras.utils.SupportedAlgorithm;
 import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
 
 /**
  * A referer of a container on a {@link OCILayout}.
@@ -43,7 +44,7 @@ public final class LayoutRef extends Ref<LayoutRef> {
      * Private constructor
      * @param tag The tag.
      */
-    private LayoutRef(Path folder, String tag) {
+    private LayoutRef(Path folder, @Nullable String tag) {
         super(tag);
         this.folder = folder;
     }
@@ -85,6 +86,25 @@ public static LayoutRef parse(String name) {
         return new LayoutRef(path, tag);
     }
 
+    /**
+     * Return a new layout reference for a path and digest or tag
+     * @param layout The OCI layout
+     * @param digest The digest
+     * @return The layout ref
+     */
+    public static LayoutRef of(OCILayout layout, String digest) {
+        return new LayoutRef(layout.getPath(), digest);
+    }
+
+    /**
+     * Return a new layout reference for a path and digest or tag
+     * @param layout The OCI layout
+     * @return The layout ref
+     */
+    public static LayoutRef of(OCILayout layout) {
+        return new LayoutRef(layout.getPath(), null);
+    }
+
     /**
      * Return a new layout reference for a path
      * @param path The path
diff --git a/src/main/java/land/oras/Ref.java b/src/main/java/land/oras/Ref.java
index b1903c0..7eb557e 100644
--- a/src/main/java/land/oras/Ref.java
+++ b/src/main/java/land/oras/Ref.java
@@ -40,7 +40,7 @@ public abstract sealed class Ref<T extends Ref<T>> permits ContainerRef, LayoutR
      * Constructor
      * @param tag The tag
      */
-    protected Ref(String tag) {
+    protected Ref(@Nullable String tag) {
         this.tag = tag;
     }
 
diff --git a/src/test/java/land/oras/OCILayoutTest.java b/src/test/java/land/oras/OCILayoutTest.java
index 6a02d25..8162e93 100644
--- a/src/test/java/land/oras/OCILayoutTest.java
+++ b/src/test/java/land/oras/OCILayoutTest.java
@@ -599,8 +599,8 @@ void shouldPushBlob() throws IOException {
         byte[] content = "hi".getBytes(StandardCharsets.UTF_8);
         String digest = SupportedAlgorithm.SHA256.digest(content);
 
-        LayoutRef layoutRef = LayoutRef.parse("%s@%s".formatted(path.toString(), digest));
         OCILayout ociLayout = OCILayout.Builder.builder().defaults(path).build();
+        LayoutRef layoutRef = LayoutRef.of(ociLayout, digest);
 
         // Push more blobs
         ociLayout.pushBlob(layoutRef, "hi".getBytes(StandardCharsets.UTF_8));
@@ -621,11 +621,12 @@ void cannotPushBlobWithoutTagOrDigest() throws IOException {
 
         Path invalidBlobPushDir = layoutPath.resolve("shouldPushArtifact");
 
-        LayoutRef noTagLayout = LayoutRef.parse("%s".formatted(invalidBlobPushDir.toString()));
-        LayoutRef noDigestLayout = LayoutRef.parse("%s:latest".formatted(invalidBlobPushDir.toString()));
         OCILayout ociLayout =
                 OCILayout.Builder.builder().defaults(invalidBlobPushDir).build();
 
+        LayoutRef noTagLayout = LayoutRef.of(ociLayout);
+        LayoutRef noDigestLayout = LayoutRef.of(ociLayout, "latest");
+
         // Push more blobs
         assertThrows(OrasException.class, () -> {
             ociLayout.pushBlob(noTagLayout, "hi".getBytes(StandardCharsets.UTF_8));
@@ -665,7 +666,7 @@ void testShouldCopyArtifactFromRegistryIntoOciLayout() throws IOException {
                 .build();
 
         OCILayout ociLayout = OCILayout.builder().defaults(layoutPath).build();
-        LayoutRef layoutRef = LayoutRef.parse("%s".formatted(ociLayout.getPath()));
+        LayoutRef layoutRef = LayoutRef.of(ociLayout);
 
         ContainerRef containerRef =
                 ContainerRef.parse("%s/library/artifact-oci-layout".formatted(this.registry.getRegistry()));