8166597: Crypto support for the EdDSA Signature Algorithm

Reviewed-by: weijun, mullan, wetmore

src/java.base/share/classes/java/security/spec/EdDSAParameterSpec.java

@@ -0,0 +1,110 @@
+/*
+ * Copyright (c) 2020, 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.spec;
+
+import java.security.InvalidParameterException;
+import java.util.Objects;
+import java.util.Optional;
+
+/**
+ * A class used to specify EdDSA signature and verification parameters. All
+ * algorithm modes in <a href="https://tools.ietf.org/html/rfc8032">RFC 8032:
+ * Edwards-Curve Digital Signature Algorithm (EdDSA)</a> can be specified using
+ * combinations of the settings in this class.
+ *
+ * <ul>
+ * <li>If prehash is true, then the mode is Ed25519ph or Ed448ph</li>
+ * <li>Otherwise, if a context is present, the mode is Ed25519ctx or Ed448</li>
+ * <li>Otherwise, the mode is Ed25519 or Ed448</li>
+ * </ul>
+ *
+ * @since 15
+ */
+
+public class EdDSAParameterSpec implements AlgorithmParameterSpec {
+
+    private final boolean prehash;
+    private final byte[] context;
+
+    /**
+     * Construct an {@code EdDSAParameterSpec} by specifying whether the prehash mode
+     * is used. No context is provided so this constructor specifies a mode
+     * in which the context is null. Note that this mode may be different
+     * than the mode in which an empty array is used as the context.
+     *
+     * @param prehash whether the prehash mode is specified.
+     */
+    public EdDSAParameterSpec(boolean prehash) {
+        this.prehash = prehash;
+        this.context = null;
+    }
+
+    /**
+     * Construct an {@code EdDSAParameterSpec} by specifying a context and whether the
+     * prehash mode is used. The context may not be null, but it may be an
+     * empty array. The mode used when the context is an empty array may not be
+     * the same as the mode used when the context is absent.
+     *
+     * @param prehash whether the prehash mode is specified.
+     * @param context the context is copied and bound to the signature.
+     * @throws NullPointerException if context is null.
+     * @throws InvalidParameterException if context length is greater than 255.
+     */
+    public EdDSAParameterSpec(boolean prehash, byte[] context) {
+
+        Objects.requireNonNull(context, "context may not be null");
+        if (context.length > 255) {
+            throw new InvalidParameterException("context length cannot be " +
+                "greater than 255");
+        }
+
+        this.prehash = prehash;
+        this.context = context.clone();
+    }
+
+    /**
+     * Get whether the prehash mode is specified.
+     *
+     * @return whether the prehash mode is specified.
+     */
+    public boolean isPrehash() {
+        return prehash;
+    }
+
+    /**
+     * Get the context that the signature will use.
+     *
+     * @return {@code Optional} contains a copy of the context or empty
+     * if context is null.
+     */
+    public Optional<byte[]> getContext() {
+        if (context == null) {
+            return Optional.empty();
+        } else {
+            return Optional.of(context.clone());
+        }
+    }
+}