diff --git a/sop-java/src/main/java/sop/operation/InlineSign.java b/sop-java/src/main/java/sop/operation/InlineSign.java
new file mode 100644
index 0000000..ed1f90b
--- /dev/null
+++ b/sop-java/src/main/java/sop/operation/InlineSign.java
@@ -0,0 +1,9 @@
+// SPDX-FileCopyrightText: 2022 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package sop.operation;
+
+public interface InlineSign {
+
+}
diff --git a/sop-java/src/main/java/sop/operation/Sign.java b/sop-java/src/main/java/sop/operation/Sign.java
index 931c80a..f02e709 100644
--- a/sop-java/src/main/java/sop/operation/Sign.java
+++ b/sop-java/src/main/java/sop/operation/Sign.java
@@ -46,6 +46,20 @@ public interface Sign {
      */
     Sign key(InputStream key) throws SOPGPException.KeyIsProtected, SOPGPException.BadData, IOException;
 
+    /**
+     * Add one or more signing keys.
+     *
+     * @param key byte array containing encoded keys
+     * @return builder instance
+     *
+     * @throws sop.exception.SOPGPException.KeyIsProtected if the key is password protected
+     * @throws sop.exception.SOPGPException.BadData if the byte array does not contain an OpenPGP key
+     * @throws IOException in case of an IO error
+     */
+    default Sign key(byte[] key) throws SOPGPException.KeyIsProtected, SOPGPException.BadData, IOException {
+        return key(new ByteArrayInputStream(key));
+    }
+
     /**
      * Provide the decryption password for the secret key.
      *
@@ -64,20 +78,6 @@ public interface Sign {
      */
     Sign withKeyPassword(byte[] password);
 
-    /**
-     * Add one or more signing keys.
-     *
-     * @param key byte array containing encoded keys
-     * @return builder instance
-     *
-     * @throws sop.exception.SOPGPException.KeyIsProtected if the key is password protected
-     * @throws sop.exception.SOPGPException.BadData if the byte array does not contain an OpenPGP key
-     * @throws IOException in case of an IO error
-     */
-    default Sign key(byte[] key) throws SOPGPException.KeyIsProtected, SOPGPException.BadData, IOException {
-        return key(new ByteArrayInputStream(key));
-    }
-
     /**
      * Signs data.
      *