diff --git a/src/XML/ds/AbstractKeyInfoType.php b/src/XML/ds/AbstractKeyInfoType.php
new file mode 100644
index 00000000..b266045f
--- /dev/null
+++ b/src/XML/ds/AbstractKeyInfoType.php
@@ -0,0 +1,117 @@
+<?php
+
+declare(strict_types=1);
+
+namespace SimpleSAML\XMLSecurity\XML\ds;
+
+use DOMElement;
+use SimpleSAML\Assert\Assert;
+use SimpleSAML\XML\Exception\SchemaViolationException;
+use SimpleSAML\XML\ExtendableElementTrait;
+use SimpleSAML\XML\SerializableElementInterface;
+use SimpleSAML\XML\XsNamespace as NS;
+use SimpleSAML\XMLSecurity\Constants as C;
+use SimpleSAML\XMLSecurity\Exception\InvalidArgumentException;
+use SimpleSAML\XMLSecurity\XML\ds\AbstractDsElement;
+
+/**
+ * Abstract class representing the KeyInfoType.
+ *
+ * @package simplesamlphp/xml-security
+ */
+abstract class AbstractKeyInfoType extends AbstractDsElement
+{
+    use ExtendableElementTrait;
+
+    /** @var \SimpleSAML\XML\XsNamespace */
+    public const XS_ANY_ELT_NAMESPACE = NS::OTHER;
+
+
+    /**
+     * Initialize a KeyInfo element.
+     *
+     * @param (
+     *     \SimpleSAML\XMLSecurity\XML\ds\KeyName|
+     *     \SimpleSAML\XMLSecurity\XML\ds\KeyValue|
+     *     \SimpleSAML\XMLSecurity\XML\ds\RetrievalMethod|
+     *     \SimpleSAML\XMLSecurity\XML\ds\X509Data|
+     *     \SimpleSAML\XML\SerializableElementInterface
+     * )[] $info
+     * @param string|null $Id
+     */
+    final public function __construct(
+        protected array $info,
+        protected ?string $Id = null,
+    ) {
+        Assert::notEmpty(
+            $info,
+            sprintf(
+                '%s:%s cannot be empty',
+                static::getNamespacePrefix(),
+                static::getLocalName(),
+            ),
+            InvalidArgumentException::class,
+        );
+        Assert::maxCount($info, C::UNBOUNDED_LIMIT);
+        Assert::allIsInstanceOf(
+            $info,
+            SerializableElementInterface::class,
+            InvalidArgumentException::class,
+        );
+        Assert::nullOrValidNCName($Id);
+
+        foreach ($info as $item) {
+            if ($item instanceof AbstractDsElement) {
+                Assert::isInstanceOfAny(
+                    $item,
+                    [KeyName::class, KeyValue::class, RetrievalMethod::class, X509Data::class],
+                    SchemaViolationException::class,
+                );
+            }
+        }
+    }
+
+
+    /**
+     * Collect the value of the Id-property
+     *
+     * @return string|null
+     */
+    public function getId(): ?string
+    {
+        return $this->Id;
+    }
+
+
+    /**
+     * Collect the value of the info-property
+     *
+     * @return list<\SimpleSAML\XML\SerializableElementInterface>
+     */
+    public function getInfo(): array
+    {
+        return $this->info;
+    }
+
+
+    /**
+     * Convert this KeyInfo to XML.
+     *
+     * @param \DOMElement|null $parent The element we should append this KeyInfo to.
+     * @return \DOMElement
+     */
+    public function toXML(DOMElement $parent = null): DOMElement
+    {
+        $e = $this->instantiateParentElement($parent);
+
+        if ($this->getId() !== null) {
+            $e->setAttribute('Id', $this->getId());
+        }
+
+        foreach ($this->getInfo() as $elt) {
+            $elt->toXML($e);
+        }
+
+        return $e;
+    }
+}
diff --git a/src/XML/ds/KeyInfo.php b/src/XML/ds/KeyInfo.php
index 1c013590..5f499345 100644
--- a/src/XML/ds/KeyInfo.php
+++ b/src/XML/ds/KeyInfo.php
@@ -7,86 +7,16 @@
 use DOMElement;
 use SimpleSAML\Assert\Assert;
 use SimpleSAML\XML\Exception\InvalidDOMElementException;
-use SimpleSAML\XML\Exception\SchemaViolationException;
-use SimpleSAML\XML\ExtendableElementTrait;
-use SimpleSAML\XML\SerializableElementInterface;
-use SimpleSAML\XML\XsNamespace as NS;
-use SimpleSAML\XMLSecurity\Constants as C;
-use SimpleSAML\XMLSecurity\Exception\InvalidArgumentException;
-use SimpleSAML\XMLSecurity\XML\ds\AbstractDsElement;
+
+use function array_merge;
 
 /**
  * Class representing a ds:KeyInfo element.
  *
  * @package simplesamlphp/xml-security
  */
-final class KeyInfo extends AbstractDsElement
+final class KeyInfo extends AbstractKeyInfoType
 {
-    use ExtendableElementTrait;
-
-    /** @var \SimpleSAML\XML\XsNamespace */
-    public const XS_ANY_ELT_NAMESPACE = NS::OTHER;
-
-
-    /**
-     * Initialize a KeyInfo element.
-     *
-     * @param (
-     *     \SimpleSAML\XMLSecurity\XML\ds\KeyName|
-     *     \SimpleSAML\XMLSecurity\XML\ds\KeyValue|
-     *     \SimpleSAML\XMLSecurity\XML\ds\RetrievalMethod|
-     *     \SimpleSAML\XMLSecurity\XML\ds\X509Data|
-     *     \SimpleSAML\XML\SerializableElementInterface
-     * )[] $info
-     * @param string|null $Id
-     */
-    public function __construct(
-        protected array $info,
-        protected ?string $Id = null,
-    ) {
-        Assert::notEmpty($info, 'ds:KeyInfo cannot be empty', InvalidArgumentException::class);
-        Assert::maxCount($info, C::UNBOUNDED_LIMIT);
-        Assert::allIsInstanceOf(
-            $info,
-            SerializableElementInterface::class,
-            InvalidArgumentException::class,
-        );
-        Assert::nullOrValidNCName($Id);
-
-        foreach ($info as $item) {
-            if ($item instanceof AbstractDsElement) {
-                Assert::isInstanceOfAny(
-                    $item,
-                    [KeyName::class, KeyValue::class, RetrievalMethod::class, X509Data::class],
-                    SchemaViolationException::class,
-                );
-            }
-        }
-    }
-
-
-    /**
-     * Collect the value of the Id-property
-     *
-     * @return string|null
-     */
-    public function getId(): ?string
-    {
-        return $this->Id;
-    }
-
-
-    /**
-     * Collect the value of the info-property
-     *
-     * @return list<\SimpleSAML\XML\SerializableElementInterface>
-     */
-    public function getInfo(): array
-    {
-        return $this->info;
-    }
-
-
     /**
      * Convert XML into a KeyInfo
      *
@@ -125,26 +55,4 @@ public static function fromXML(DOMElement $xml): static
 
         return new static($info, $Id);
     }
-
-
-    /**
-     * Convert this KeyInfo to XML.
-     *
-     * @param \DOMElement|null $parent The element we should append this KeyInfo to.
-     * @return \DOMElement
-     */
-    public function toXML(DOMElement $parent = null): DOMElement
-    {
-        $e = $this->instantiateParentElement($parent);
-
-        if ($this->getId() !== null) {
-            $e->setAttribute('Id', $this->getId());
-        }
-
-        foreach ($this->getInfo() as $elt) {
-            $elt->toXML($e);
-        }
-
-        return $e;
-    }
 }