verify method for json strings (#37)

nostrver-se · Nov 16, 2023 · 7ba76da · 7ba76da
1 parent bd9f4d8
commit 7ba76da
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Showing 2 changed files with 93 additions and 1 deletion.
diff --git a/src/Event/Event.php b/src/Event/Event.php
@@ -2,6 +2,7 @@
 
 namespace swentel\nostr\Event;
 
+use Mdanter\Ecc\Crypto\Signature\SchnorrSignature;
 use swentel\nostr\EventInterface;
 
 class Event implements EventInterface
@@ -68,6 +69,60 @@ public function __construct()
         $this->setKind($this->kind);
     }
 
+    /**
+     * Returns true if $json encodes a valid Nostr event.
+     */
+    public static function verify(string $json): bool
+    {
+        try {
+            $event = json_decode($json, flags: \JSON_UNESCAPED_SLASHES | \JSON_UNESCAPED_UNICODE | \JSON_THROW_ON_ERROR);
+        } catch (\JsonException) {
+            return false;
+        }
+
+        if (!$event instanceof \stdClass
+            || !property_exists($event, 'id')
+            || !property_exists($event, 'pubkey')
+            || !property_exists($event, 'created_at')
+            || !property_exists($event, 'kind')
+            || !property_exists($event, 'tags')
+            || !property_exists($event, 'content')
+            || !property_exists($event, 'sig')
+            || !is_string($event->id)
+            || !is_string($event->pubkey)
+            || !is_int($event->created_at)
+            || !is_int($event->kind)
+            || !is_array($event->tags)
+            || !is_string($event->content)
+            || !is_string($event->sig)
+        ) {
+            return false;
+        }
+
+        foreach ($event->tags as $tag) {
+            if (!is_array($tag)) {
+                return false;
+            }
+
+            foreach ($tag as $value) {
+                if (!is_string($value)) {
+                    return false;
+                }
+            }
+        }
+
+        $computedId = hash('sha256', json_encode(
+            [0, $event->pubkey, $event->created_at, $event->kind, $event->tags, $event->content],
+            \JSON_UNESCAPED_SLASHES | \JSON_UNESCAPED_UNICODE
+        ));
+
+        if (!hash_equals($computedId, $event->id)) {
+            return false;
+        }
+
+        return (new SchnorrSignature())->verify($event->pubkey, $event->sig, $event->id);
+    }
+
     /**
      * {@inheritdoc}
      */
@@ -212,4 +267,4 @@ public function toArray(array $ignore_properties = []): array
         return $array;
     }
 
-}
+}
diff --git a/tests/VerifyTest.php b/tests/VerifyTest.php
@@ -0,0 +1,37 @@
+<?php
+
+use PHPUnit\Framework\TestCase;
+use swentel\nostr\Event\Event;
+
+class VerifyTest extends TestCase
+{
+    public function testValidEventValidation()
+    {
+        $json = '{"id":"ac21a6c4cb128a27c0b9a229bc1fa8e7167660664354d5e5a481825d01188108","pubkey":"7543c184ff776be3c13d2437894494173cfea4e9919d48fb2934216a13a53c58","created_at":1697800339,"kind":1,"tags":[["e","5361bb83c899cf75589a25c32cea5b868d4990da41fd4dba84144eede5ad1359"],["p","d4dea80c64ebd3f9bc8271893191dbc851ecd2b7bcb811bb87386b5158ee735d"]],"content":"Gm ☕️⚡️🌅","sig":"46a9d4f4470bdf685d4fc4f664d1d4c8576e501cfe0ccf044ba65d36c3ee66eab3f261d524a4bdbde71bc2d921c13829a5ac596538ded74125f5060d4f3f805d"}';
+
+        $this->assertTrue(Event::verify($json));
+    }
+
+    /**
+     * @dataProvider invalidEventsProvider
+     */
+    public function testInvalidEventsValidation(string $json)
+    {
+        $this->assertFalse(Event::verify($json));
+    }
+
+    public static function invalidEventsProvider(): array
+    {
+        return [
+            'not json'          => ['Craig Wright is not Satoshi Nakamoto'],
+            'non object'        => ['[1,2,3'],
+            'empty json'        => ['{}'],
+            'meaningless json'  => ['{"foo":"bar"}'],
+            'missing fields'    => ['{"id":"ac21a6c4cb128a27c0b9a229bc1fa8e7167660664354d5e5a481825d01188108","pubkey":"7543c184ff776be3c13d2437894494173cfea4e9919d48fb2934216a13a53c58","created_at":1697800339,"kind":1}'],
+            'invalid tag'       => ['{"id":"ac21a6c4cb128a27c0b9a229bc1fa8e7167660664354d5e5a481825d01188108","pubkey":"7543c184ff776be3c13d2437894494173cfea4e9919d48fb2934216a13a53c58","created_at":1697800339,"kind":1,"tags":[1234,["p","d4dea80c64ebd3f9bc8271893191dbc851ecd2b7bcb811bb87386b5158ee735d"]],"content":"Gm ☕️⚡️🌅","sig":"46a9d4f4470bdf685d4fc4f664d1d4c8576e501cfe0ccf044ba65d36c3ee66eab3f261d524a4bdbde71bc2d921c13829a5ac596538ded74125f5060d4f3f805d"}'],
+            'invalid tag value' => ['{"id":"ac21a6c4cb128a27c0b9a229bc1fa8e7167660664354d5e5a481825d01188108","pubkey":"7543c184ff776be3c13d2437894494173cfea4e9919d48fb2934216a13a53c58","created_at":1697800339,"kind":1,"tags":[[123,"5361bb83c899cf75589a25c32cea5b868d4990da41fd4dba84144eede5ad1359"],["p","d4dea80c64ebd3f9bc8271893191dbc851ecd2b7bcb811bb87386b5158ee735d"]],"content":"Gm ☕️⚡️🌅","sig":"46a9d4f4470bdf685d4fc4f664d1d4c8576e501cfe0ccf044ba65d36c3ee66eab3f261d524a4bdbde71bc2d921c13829a5ac596538ded74125f5060d4f3f805d"}'],
+            'invalid id'        => ['{"id":"bc21a6c4cb128a27c0b9a229bc1fa8e7167660664354d5e5a481825d01188108","pubkey":"7543c184ff776be3c13d2437894494173cfea4e9919d48fb2934216a13a53c58","created_at":1697800339,"kind":1,"tags":[["e","5361bb83c899cf75589a25c32cea5b868d4990da41fd4dba84144eede5ad1359"],["p","d4dea80c64ebd3f9bc8271893191dbc851ecd2b7bcb811bb87386b5158ee735d"]],"content":"Gm ☕️⚡️🌅","sig":"46a9d4f4470bdf685d4fc4f664d1d4c8576e501cfe0ccf044ba65d36c3ee66eab3f261d524a4bdbde71bc2d921c13829a5ac596538ded74125f5060d4f3f805d"}'],
+            'invalid sig'       => ['{"id":"ac21a6c4cb128a27c0b9a229bc1fa8e7167660664354d5e5a481825d01188108","pubkey":"7543c184ff776be3c13d2437894494173cfea4e9919d48fb2934216a13a53c58","created_at":1697800339,"kind":1,"tags":[["e","5361bb83c899cf75589a25c32cea5b868d4990da41fd4dba84144eede5ad1359"],["p","d4dea80c64ebd3f9bc8271893191dbc851ecd2b7bcb811bb87386b5158ee735d"]],"content":"Gm ☕️⚡️🌅","sig":"56a9d4f4470bdf685d4fc4f664d1d4c8576e501cfe0ccf044ba65d36c3ee66eab3f261d524a4bdbde71bc2d921c13829a5ac596538ded74125f5060d4f3f805d"}']
+        ];
+    }
+}