Feature/issue 157

nostr-java-api/src/main/java/module-info.java

@@ -14,6 +14,7 @@
 
     requires lombok;
     requires java.logging;
+    requires nostr.crypto;
 
     exports nostr.api;
 }

nostr-java-api/src/main/java/nostr/api/Nostr.java

@@ -15,6 +15,7 @@
 import nostr.client.Client;
 import nostr.context.RequestContext;
 import nostr.context.impl.DefaultRequestContext;
+import nostr.crypto.schnorr.Schnorr;
 import nostr.event.BaseEvent;
 import nostr.event.BaseMessage;
 import nostr.event.BaseTag;
@@ -33,6 +34,7 @@
 import nostr.event.message.EventMessage;
 import nostr.event.message.ReqMessage;
 import nostr.id.Identity;
+import nostr.util.NostrUtil;
 
 import java.util.HashMap;
 import java.util.List;
@@ -146,6 +148,21 @@ public Nostr sign(@NonNull Identity identity, @NonNull ISignable signable) {
         return this;
     }
 
+    public boolean verify(@NonNull GenericEvent event) {
+        if (!event.isSigned()) {
+            throw new IllegalStateException("The event is not signed");
+        }
+
+        var signature = event.getSignature();
+
+        try {
+            var message = NostrUtil.sha256(event.get_serializedEvent());
+            return Schnorr.verify(message, event.getPubKey().getRawData(), signature.getRawData());
+        } catch (Exception e) {
+            throw new RuntimeException(e);
+        }
+    }
+
     private static Map<String, String> toMapRelays(List<Relay> relayList) {
         Map<String, String> relays = new HashMap<>();
         relayList.forEach(r -> relays.put(r.getName(), r.getUri()));

nostr-java-crypto/src/main/java/nostr/crypto/schnorr/Schnorr.java

@@ -1,5 +1,9 @@
 package nostr.crypto.schnorr;
 
+import nostr.crypto.Point;
+import nostr.util.NostrUtil;
+import org.bouncycastle.jce.provider.BouncyCastleProvider;
+
 import java.math.BigInteger;
 import java.security.InvalidAlgorithmParameterException;
 import java.security.KeyPair;
@@ -12,11 +16,6 @@
 import java.security.spec.ECGenParameterSpec;
 import java.util.Arrays;
 
-import org.bouncycastle.jce.provider.BouncyCastleProvider;
-
-import nostr.crypto.Point;
-import nostr.util.NostrUtil;
-
 public class Schnorr {
 
     /**
@@ -86,9 +85,11 @@ public static byte[] sign(byte[] msg, byte[] secKey, byte[] auxRand) throws Exce
      * @throws Exception
      */
     public static boolean verify(byte[] msg, byte[] pubkey, byte[] sig) throws Exception {
+
         if (msg.length != 32) {
             throw new Exception("The message must be a 32-byte array.");
         }
+
         if (pubkey.length != 32) {
             throw new Exception("The public key must be a 32-byte array.");
         }

nostr-java-test/src/test/java/nostr/test/crypto/CryptoTest.java

@@ -1,11 +1,18 @@
 package nostr.test.crypto;
 
-import org.junit.jupiter.api.Assertions;
-import org.junit.jupiter.api.Test;
-
 import nostr.crypto.bech32.Bech32;
 import nostr.crypto.bech32.Bech32Prefix;
+import nostr.crypto.schnorr.Schnorr;
+import nostr.event.impl.GenericEvent;
+import nostr.id.Identity;
 import nostr.util.NostrException;
+import nostr.util.NostrUtil;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+import static nostr.test.EntityFactory.Events.createTextNoteEvent;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 /**
  *
@@ -27,4 +34,25 @@ public void testBech32() {
             Assertions.fail(ex);
         }
     }
+
+    @Test
+    public void testVerifySignature() throws Exception {
+        System.out.println("testVerifySignature");
+
+        Identity identity = Identity.generateRandomIdentity();
+        GenericEvent event = createTextNoteEvent(identity.getPublicKey(), "Hello World");
+        event.update();
+        var message = NostrUtil.sha256(event.get_serializedEvent());
+        var signature = identity.sign(event);
+        var verification = Schnorr.verify(message, identity.getPublicKey().getRawData(), signature.getRawData());
+        assertTrue(verification);
+
+        event = createTextNoteEvent(identity.getPublicKey(), "Guten Tag");
+        event.update();
+        message = NostrUtil.sha256(event.get_serializedEvent());
+        verification = Schnorr.verify(message, identity.getPublicKey().getRawData(), signature.getRawData());
+
+        assertFalse(verification);
+    }
+
 }