From 7cb20f83c59358e5e30ebde85c7e6d0c13533b31 Mon Sep 17 00:00:00 2001
From: Paul Schaub <vanitasvitae@fsfe.org>
Date: Sun, 2 Jun 2024 15:02:14 +0200
Subject: [PATCH] Test conversion of Ed448 keys with leading zero

---
 .../test/Ed448ConversionWithLeadingZero.java  | 81 +++++++++++++++++++
 1 file changed, 81 insertions(+)
 create mode 100644 pg/src/test/java/org/bouncycastle/openpgp/test/Ed448ConversionWithLeadingZero.java

diff --git a/pg/src/test/java/org/bouncycastle/openpgp/test/Ed448ConversionWithLeadingZero.java b/pg/src/test/java/org/bouncycastle/openpgp/test/Ed448ConversionWithLeadingZero.java
new file mode 100644
index 0000000000..4c083806ba
--- /dev/null
+++ b/pg/src/test/java/org/bouncycastle/openpgp/test/Ed448ConversionWithLeadingZero.java
@@ -0,0 +1,81 @@
+package org.bouncycastle.openpgp.test;
+
+import org.bouncycastle.bcpg.PublicKeyAlgorithmTags;
+import org.bouncycastle.bcpg.test.AbstractPacketTest;
+import org.bouncycastle.jce.provider.BouncyCastleProvider;
+import org.bouncycastle.openpgp.PGPException;
+import org.bouncycastle.openpgp.PGPKeyPair;
+import org.bouncycastle.openpgp.operator.jcajce.JcaPGPKeyConverter;
+import org.bouncycastle.openpgp.operator.jcajce.JcaPGPKeyPair;
+import org.bouncycastle.util.encoders.Hex;
+
+import java.io.IOException;
+import java.security.*;
+import java.security.spec.*;
+import java.util.Date;
+
+public class Ed448ConversionWithLeadingZero
+        extends AbstractPacketTest
+{
+    @Override
+    public String getName()
+    {
+        return "Ed448LeadingZero";
+    }
+
+    private static final String ED448_KEY_WITH_LEADING_ZERO = "308183020101300506032b6571043b0439fe2c82fd07b0e8b5da002ee4964e55a357bfdd2192fe43a40b150e6c5a8f8202f140dd34ede17dc10fef9a98bf8188425c14bd1a76a308cfb7813a0000728cbb07c590e2cb282834cc22d7a1f775f729986c4754e7035695dee34057403e98e94cf5012007c3236f4894af039e668acb746fcf8a00";
+    private static final String ED448_PUB_WITH_LEADING_ZERO = "3043300506032b6571033a0000728cbb07c590e2cb282834cc22d7a1f775f729986c4754e7035695dee34057403e98e94cf5012007c3236f4894af039e668acb746fcf8a00";
+
+    @Override
+    public void performTest()
+            throws Exception
+    {
+        testWithEd448KeyWithLeadingZero();
+    }
+
+    private void testWithEd448KeyWithLeadingZero()
+            throws NoSuchAlgorithmException, InvalidKeySpecException, PGPException, InvalidKeyException, SignatureException
+    {
+        JcaPGPKeyConverter jcaPGPKeyConverter = new JcaPGPKeyConverter().setProvider(new BouncyCastleProvider());
+
+        KeyFactory factory = KeyFactory.getInstance("EdDSA", new BouncyCastleProvider());
+
+        PublicKey pubKey = factory.generatePublic(new X509EncodedKeySpec(Hex.decode(ED448_PUB_WITH_LEADING_ZERO)));
+        PrivateKey privKey = factory.generatePrivate(new PKCS8EncodedKeySpec(Hex.decode(ED448_KEY_WITH_LEADING_ZERO)));
+        KeyPair keyPair = new KeyPair(pubKey, privKey);
+
+        Date creationDate = new Date();
+        PGPKeyPair jcaPgpPair = new JcaPGPKeyPair(PublicKeyAlgorithmTags.Ed448, keyPair, creationDate);
+        isTrue("public key encoding before conversion MUST have leading 0",
+                jcaPgpPair.getPublicKey().getPublicKeyPacket().getKey().getEncoded()[0] == 0); // leading 0
+
+        PublicKey cPubKey = jcaPGPKeyConverter.getPublicKey(jcaPgpPair.getPublicKey());
+        PrivateKey cPrivKey = jcaPGPKeyConverter.getPrivateKey(jcaPgpPair.getPrivateKey());
+
+        testSignature(cPrivKey, pubKey);
+        testSignature(privKey, cPubKey);
+
+        jcaPgpPair = new JcaPGPKeyPair(PublicKeyAlgorithmTags.Ed448, new KeyPair(cPubKey, cPrivKey), creationDate);
+        isTrue("public key encoding after conversion MUST have leading 0",
+                jcaPgpPair.getPublicKey().getPublicKeyPacket().getKey().getEncoded()[0] == 0); // leading 0 is preserved
+    }
+
+    private void testSignature(PrivateKey privateKey, PublicKey publicKey)
+            throws NoSuchAlgorithmException, SignatureException, InvalidKeyException
+    {
+        Signature signature = Signature.getInstance("Ed448", new BouncyCastleProvider());
+        signature.initSign(privateKey);
+        signature.update("Hello, World!\n".getBytes());
+        byte[] sig = signature.sign();
+
+        signature.initVerify(publicKey);
+        signature.update("Hello, World!\n".getBytes());
+        isTrue("Signature MUST verify", signature.verify(sig));
+    }
+
+    public static void main(String[] args)
+    {
+        Security.addProvider(new BouncyCastleProvider());
+        runTest(new Ed448ConversionWithLeadingZero());
+    }
+}