8298420: Implement JEP 470: PEM Encodings of Cryptographic Objects (Preview)

src/java.base/share/classes/java/security/AsymmetricKey.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2023, 2025, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -34,7 +34,7 @@
  *
  * @since 22
  */
-public interface AsymmetricKey extends Key {
+public non-sealed interface AsymmetricKey extends Key, DEREncodable {
     /**
      * Returns the parameters associated with this key.
      * The parameters are optional and may be either

src/java.base/share/classes/java/security/DEREncodable.java

@@ -0,0 +1,59 @@
+/*
+ * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package java.security;
+
+import jdk.internal.javac.PreviewFeature;
+
+import javax.crypto.EncryptedPrivateKeyInfo;
+import java.security.cert.X509CRL;
+import java.security.cert.X509Certificate;
+import java.security.spec.PKCS8EncodedKeySpec;
+import java.security.spec.X509EncodedKeySpec;
+
+/**
+ * This interface is implemented by security API classes that contain
+ * binary-encodable key or certificate material.
+ * These APIs or their subclasses typically provide methods to convert
+ * their instances to and from byte arrays in the Distinguished
+ * Encoding Rules (DER) format.
+ *
+ * @see AsymmetricKey
+ * @see KeyPair
+ * @see PKCS8EncodedKeySpec
+ * @see X509EncodedKeySpec
+ * @see EncryptedPrivateKeyInfo
+ * @see X509Certificate
+ * @see X509CRL
+ * @see PEMRecord
+ *
+ * @since 25
+ */
+
+@PreviewFeature(feature = PreviewFeature.Feature.PEM_API)
+public sealed interface DEREncodable permits AsymmetricKey, KeyPair,
+    PKCS8EncodedKeySpec, X509EncodedKeySpec, EncryptedPrivateKeyInfo,
+    X509Certificate, X509CRL, PEMRecord {
+}

src/java.base/share/classes/java/security/KeyPair.java

@@ -37,7 +37,7 @@
  * @since 1.1
  */
 
-public final class KeyPair implements java.io.Serializable {
+public final class KeyPair implements java.io.Serializable, DEREncodable {
 
     @java.io.Serial
     private static final long serialVersionUID = -7565189502268009837L;