diff --git a/sop-java/src/main/java/sop/SigningResult.java b/sop-java/src/main/java/sop/SigningResult.java
deleted file mode 100644
index 1ea1ba8..0000000
--- a/sop-java/src/main/java/sop/SigningResult.java
+++ /dev/null
@@ -1,50 +0,0 @@
-// SPDX-FileCopyrightText: 2021 Paul Schaub <vanitasvitae@fsfe.org>
-//
-// SPDX-License-Identifier: Apache-2.0
-
-package sop;
-
-/**
- * This class contains various information about a signed message.
- */
-public final class SigningResult {
-
-    private final MicAlg micAlg;
-
-    private SigningResult(MicAlg micAlg) {
-        this.micAlg = micAlg;
-    }
-
-    /**
-     * Return a string identifying the digest mechanism used to create the signed message.
-     * This is useful for setting the micalg= parameter for the multipart/signed
-     * content type of a PGP/MIME object as described in section 5 of [RFC3156].
-     * <p>
-     * If more than one signature was generated and different digest mechanisms were used,
-     * the value of the micalg object is an empty string.
-     *
-     * @return micalg
-     */
-    public MicAlg getMicAlg() {
-        return micAlg;
-    }
-
-    public static Builder builder() {
-        return new Builder();
-    }
-
-    public static class Builder {
-
-        private MicAlg micAlg;
-
-        public Builder setMicAlg(MicAlg micAlg) {
-            this.micAlg = micAlg;
-            return this;
-        }
-
-        public SigningResult build() {
-            SigningResult signingResult = new SigningResult(micAlg);
-            return signingResult;
-        }
-    }
-}
diff --git a/sop-java/src/main/kotlin/sop/SigningResult.kt b/sop-java/src/main/kotlin/sop/SigningResult.kt
new file mode 100644
index 0000000..29304ea
--- /dev/null
+++ b/sop-java/src/main/kotlin/sop/SigningResult.kt
@@ -0,0 +1,28 @@
+// SPDX-FileCopyrightText: 2023 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package sop
+
+/**
+ * This class contains various information about a signed message.
+ *
+ * @param micAlg string identifying the digest mechanism used to create the signed message. This is
+ *   useful for setting the `micalg=` parameter for the multipart/signed content-type of a PGP/MIME
+ *   object as described in section 5 of [RFC3156]. If more than one signature was generated and
+ *   different digest mechanisms were used, the value of the micalg object is an empty string.
+ */
+data class SigningResult(val micAlg: MicAlg) {
+
+    class Builder internal constructor() {
+        private var micAlg = MicAlg.empty()
+
+        fun setMicAlg(micAlg: MicAlg) = apply { this.micAlg = micAlg }
+
+        fun build() = SigningResult(micAlg)
+    }
+
+    companion object {
+        @JvmStatic fun builder() = Builder()
+    }
+}