diff --git a/.beads/last-touched b/.beads/last-touched
index 6268903..cdadab4 100644
--- a/.beads/last-touched
+++ b/.beads/last-touched
@@ -1 +1 @@
-fotospiel-app-v00l
+fotospiel-app-e05
diff --git a/app/Console/Commands/MonitorStorageCommand.php b/app/Console/Commands/MonitorStorageCommand.php
index ec7cda9..89636c4 100644
--- a/app/Console/Commands/MonitorStorageCommand.php
+++ b/app/Console/Commands/MonitorStorageCommand.php
@@ -46,6 +46,12 @@ class MonitorStorageCommand extends Command
 
             $assetStats = $this->buildAssetStatistics();
             $thresholds = $this->capacityThresholds();
+            $checksumConfig = $this->checksumAlertConfig();
+            $checksumWindowMinutes = $checksumConfig['window_minutes'];
+            $checksumThresholds = $checksumConfig['thresholds'];
+            $checksumMismatches = $checksumConfig['enabled'] && $checksumWindowMinutes > 0
+                ? $this->checksumMismatchCounts($checksumWindowMinutes)
+                : [];
             $alerts = [];
             $snapshotTargets = [];
 
@@ -78,6 +84,7 @@ class MonitorStorageCommand extends Command
                     ];
                 }
 
+                $targetChecksumMismatches = $checksumMismatches[$target->id] ?? 0;
                 $snapshotTargets[] = [
                     'id' => $target->id,
                     'key' => $target->key,
@@ -85,13 +92,35 @@ class MonitorStorageCommand extends Command
                     'is_hot' => (bool) $target->is_hot,
                     'capacity' => $capacity,
                     'assets' => $assets,
+                    'checksum_mismatches' => [
+                        'count' => $targetChecksumMismatches,
+                        'window_minutes' => $checksumWindowMinutes,
+                    ],
                 ];
             }
 
+            if ($checksumConfig['enabled'] && $checksumWindowMinutes > 0) {
+                $totalMismatches = array_sum($checksumMismatches);
+                $checksumSeverity = $this->determineChecksumSeverity($totalMismatches, $checksumThresholds);
+
+                if ($checksumSeverity !== 'ok') {
+                    $alerts[] = [
+                        'type' => 'checksum_mismatch',
+                        'severity' => $checksumSeverity,
+                        'count' => $totalMismatches,
+                        'window_minutes' => $checksumWindowMinutes,
+                    ];
+                }
+            }
+
             $snapshot = [
                 'generated_at' => now()->toIso8601String(),
                 'targets' => $snapshotTargets,
                 'alerts' => $alerts,
+                'checksum' => [
+                    'window_minutes' => $checksumWindowMinutes,
+                    'mismatch_total' => array_sum($checksumMismatches),
+                ],
             ];
 
             $ttlMinutes = max(1, (int) config('storage-monitor.monitor.cache_minutes', 15));
@@ -191,4 +220,62 @@ class MonitorStorageCommand extends Command
 
         return 'ok';
     }
+
+    private function checksumAlertConfig(): array
+    {
+        $enabled = (bool) config('storage-monitor.checksum_validation.enabled', true);
+        $windowMinutes = max(0, (int) config('storage-monitor.checksum_validation.alert_window_minutes', 60));
+        $warning = (int) config('storage-monitor.checksum_validation.thresholds.warning', 1);
+        $critical = (int) config('storage-monitor.checksum_validation.thresholds.critical', 5);
+
+        if ($warning > $critical && $critical > 0) {
+            [$warning, $critical] = [$critical, $warning];
+        }
+
+        return [
+            'enabled' => $enabled,
+            'window_minutes' => $windowMinutes,
+            'thresholds' => [
+                'warning' => $warning,
+                'critical' => $critical,
+            ],
+        ];
+    }
+
+    private function checksumMismatchCounts(int $windowMinutes): array
+    {
+        $query = EventMediaAsset::query()
+            ->selectRaw('media_storage_target_id, COUNT(*) as total_count')
+            ->where('status', 'failed')
+            ->where('meta->checksum_status', 'mismatch');
+
+        if ($windowMinutes > 0) {
+            $query->where('updated_at', '>=', now()->subMinutes($windowMinutes));
+        }
+
+        return $query->groupBy('media_storage_target_id')
+            ->get()
+            ->mapWithKeys(fn ($row) => [(int) $row->media_storage_target_id => (int) $row->total_count])
+            ->all();
+    }
+
+    private function determineChecksumSeverity(int $count, array $thresholds): string
+    {
+        $warning = (int) ($thresholds['warning'] ?? 1);
+        $critical = (int) ($thresholds['critical'] ?? 5);
+
+        if ($count <= 0) {
+            return 'ok';
+        }
+
+        if ($critical > 0 && $count >= $critical) {
+            return 'critical';
+        }
+
+        if ($warning > 0 && $count >= $warning) {
+            return 'warning';
+        }
+
+        return 'ok';
+    }
 }
diff --git a/app/Jobs/ArchiveEventMediaAssets.php b/app/Jobs/ArchiveEventMediaAssets.php
index 33b9f37..1083ac5 100644
--- a/app/Jobs/ArchiveEventMediaAssets.php
+++ b/app/Jobs/ArchiveEventMediaAssets.php
@@ -71,12 +71,44 @@ class ArchiveEventMediaAssets implements ShouldQueue
 
                 Storage::disk($archiveDisk)->put($archivePath, $stream);
 
+                $checksumMeta = null;
+                $archiveChecksum = null;
+                if ($this->checksumValidationEnabled()) {
+                    $archiveChecksum = $this->computeChecksum($archiveDisk, $archivePath);
+                    if (! $archiveChecksum) {
+                        throw new \RuntimeException('Archive checksum unavailable');
+                    }
+
+                    $expectedChecksum = $asset->checksum;
+                    if ($expectedChecksum) {
+                        if (! hash_equals($expectedChecksum, $archiveChecksum)) {
+                            $this->handleChecksumMismatch($asset, $expectedChecksum, $archiveChecksum, $sourceDisk, $archiveDisk);
+                            $this->deleteArchiveCopy($archiveDisk, $archivePath);
+
+                            continue;
+                        }
+
+                        $checksumMeta = [
+                            'checksum_status' => 'verified',
+                            'checksum_verified_at' => now()->toIso8601String(),
+                        ];
+                    } else {
+                        $asset->checksum = $archiveChecksum;
+                        $checksumMeta = [
+                            'checksum_status' => 'seeded',
+                            'checksum_verified_at' => now()->toIso8601String(),
+                        ];
+                    }
+                }
+
                 $asset->fill([
                     'disk' => $archiveDisk,
                     'media_storage_target_id' => $archiveTargetId,
                     'status' => 'archived',
                     'archived_at' => now(),
                     'error_message' => null,
+                    'checksum' => $asset->checksum,
+                    'meta' => $this->mergeMeta($asset->meta, $checksumMeta),
                 ])->save();
 
                 if ($this->deleteSource) {
@@ -102,4 +134,92 @@ class ArchiveEventMediaAssets implements ShouldQueue
             }
         }
     }
+
+    private function checksumValidationEnabled(): bool
+    {
+        return (bool) config('storage-monitor.checksum_validation.enabled', true);
+    }
+
+    private function computeChecksum(string $disk, string $path): ?string
+    {
+        try {
+            $stream = Storage::disk($disk)->readStream($path);
+        } catch (\Throwable $e) {
+            Log::channel('storage-jobs')->warning('Failed to open stream for checksum', [
+                'disk' => $disk,
+                'path' => $path,
+                'error' => $e->getMessage(),
+            ]);
+
+            return null;
+        }
+
+        if (! $stream) {
+            return null;
+        }
+
+        try {
+            $context = hash_init('sha256');
+            $ok = hash_update_stream($context, $stream);
+            if ($ok === false) {
+                return null;
+            }
+
+            return hash_final($context);
+        } finally {
+            if (is_resource($stream)) {
+                fclose($stream);
+            }
+        }
+    }
+
+    private function handleChecksumMismatch(
+        EventMediaAsset $asset,
+        string $expectedChecksum,
+        string $actualChecksum,
+        string $sourceDisk,
+        string $archiveDisk,
+    ): void {
+        Log::channel('storage-jobs')->alert('Checksum mismatch detected during archive', [
+            'asset_id' => $asset->id,
+            'event_id' => $asset->event_id,
+            'source_disk' => $sourceDisk,
+            'archive_disk' => $archiveDisk,
+            'expected_checksum' => $expectedChecksum,
+            'actual_checksum' => $actualChecksum,
+        ]);
+
+        $asset->update([
+            'status' => 'failed',
+            'error_message' => 'checksum_mismatch',
+            'meta' => $this->mergeMeta($asset->meta, [
+                'checksum_status' => 'mismatch',
+                'checksum_verified_at' => now()->toIso8601String(),
+                'checksum_expected' => $expectedChecksum,
+                'checksum_actual' => $actualChecksum,
+            ]),
+        ]);
+    }
+
+    private function deleteArchiveCopy(string $archiveDisk, string $path): void
+    {
+        try {
+            Storage::disk($archiveDisk)->delete($path);
+        } catch (\Throwable $e) {
+            Log::channel('storage-jobs')->warning('Failed to clean up archive copy after checksum mismatch', [
+                'disk' => $archiveDisk,
+                'path' => $path,
+                'error' => $e->getMessage(),
+            ]);
+        }
+    }
+
+    private function mergeMeta(?array $meta, ?array $updates): ?array
+    {
+        if (! $updates) {
+            return $meta;
+        }
+
+        return array_merge($meta ?? [], $updates);
+    }
 }
diff --git a/config/storage-monitor.php b/config/storage-monitor.php
index 598c1bd..1c4101f 100644
--- a/config/storage-monitor.php
+++ b/config/storage-monitor.php
@@ -12,6 +12,15 @@ return [
         'critical' => (int) env('STORAGE_CAPACITY_CRITICAL', 90),
     ],
 
+    'checksum_validation' => [
+        'enabled' => (bool) env('STORAGE_CHECKSUM_VALIDATION', true),
+        'alert_window_minutes' => (int) env('STORAGE_CHECKSUM_ALERT_WINDOW_MINUTES', 60),
+        'thresholds' => [
+            'warning' => (int) env('STORAGE_CHECKSUM_WARNING', 1),
+            'critical' => (int) env('STORAGE_CHECKSUM_CRITICAL', 5),
+        ],
+    ],
+
     'monitor' => [
         'lock_seconds' => (int) env('STORAGE_MONITOR_LOCK_SECONDS', 300),
         'cache_minutes' => (int) env('STORAGE_MONITOR_CACHE_MINUTES', 15),
diff --git a/docs/ops/media-storage-spec.md b/docs/ops/media-storage-spec.md
index 04f37c4..2f40ad9 100644
--- a/docs/ops/media-storage-spec.md
+++ b/docs/ops/media-storage-spec.md
@@ -59,6 +59,7 @@ This document explains how customer photo uploads move through the Fotospiel pla
 | Security queue | `.env SECURITY_SCAN_QUEUE` & `config/security.php` | Defaults to `media-security`. |
 | Archive scheduling | `config/storage-monitor.php['archive']` | Controls grace days, chunk size, locking, and dispatch caps. |
 | Queue health alerts | `config/storage-monitor.php['queue_health']` | Warning/critical thresholds for `media-storage` and `media-security` queues. |
+| Checksum alerts | `config/storage-monitor.php['checksum_validation']` | Enables checksum verification alerts and thresholding window. |
 | Container volumes | `docker-compose.yml` | `app`, workers, and scheduler share the `app-code` volume so `/var/www/html/storage` is common. |
 
 ## Operational Checklist
@@ -72,6 +73,7 @@ This document explains how customer photo uploads move through the Fotospiel pla
   - Watch `storage:monitor` output (email or logs) for capacity warnings on hot disks.
   - Use Horizon or Redis metrics to verify `media-storage` queue depth; thresholds live in `config/storage-monitor.php`.
   - Review `/var/www/html/storage/logs/storage-jobs.log` (if configured) for archival failures.
+  - Checksum mismatches (hot→archive) are flagged by `storage:monitor` using `checksum_validation` thresholds.
   - Ensure `media-security` queue stays below critical thresholds so uploads aren’t blocked awaiting security scans.
 
 - **Troubleshooting uploads**
diff --git a/tests/Feature/ArchiveEventMediaAssetsTest.php b/tests/Feature/ArchiveEventMediaAssetsTest.php
new file mode 100644
index 0000000..ee2d98a
--- /dev/null
+++ b/tests/Feature/ArchiveEventMediaAssetsTest.php
@@ -0,0 +1,129 @@
+<?php
+
+namespace Tests\Feature;
+
+use App\Jobs\ArchiveEventMediaAssets;
+use App\Models\Event;
+use App\Models\EventMediaAsset;
+use App\Models\MediaStorageTarget;
+use App\Services\Storage\EventStorageManager;
+use Illuminate\Foundation\Testing\RefreshDatabase;
+use Illuminate\Support\Facades\Storage;
+use Tests\TestCase;
+
+class ArchiveEventMediaAssetsTest extends TestCase
+{
+    use RefreshDatabase;
+
+    public function test_archives_asset_and_verifies_checksum(): void
+    {
+        Storage::fake('hot-disk');
+        Storage::fake('archive-disk');
+
+        $hotTarget = MediaStorageTarget::create([
+            'key' => 'hot-disk',
+            'name' => 'Hot Disk',
+            'driver' => 'local',
+            'config' => [],
+            'is_hot' => true,
+            'is_default' => true,
+            'is_active' => true,
+            'priority' => 100,
+        ]);
+
+        MediaStorageTarget::create([
+            'key' => 'archive-disk',
+            'name' => 'Archive Disk',
+            'driver' => 'local',
+            'config' => [],
+            'is_hot' => false,
+            'is_default' => true,
+            'is_active' => true,
+            'priority' => 100,
+        ]);
+
+        $event = Event::factory()->create();
+        $path = 'events/'.$event->id.'/photo.jpg';
+        Storage::disk('hot-disk')->put($path, 'photo-body');
+
+        $checksum = hash('sha256', 'photo-body');
+
+        $asset = EventMediaAsset::create([
+            'event_id' => $event->id,
+            'media_storage_target_id' => $hotTarget->id,
+            'photo_id' => null,
+            'variant' => 'original',
+            'disk' => 'hot-disk',
+            'path' => $path,
+            'size_bytes' => 10,
+            'checksum' => $checksum,
+            'status' => 'hot',
+        ]);
+
+        (new ArchiveEventMediaAssets($event->id, true))->handle(app(EventStorageManager::class));
+
+        $asset->refresh();
+
+        $this->assertSame('archived', $asset->status);
+        $this->assertSame('archive-disk', $asset->disk);
+        $this->assertSame('verified', data_get($asset->meta, 'checksum_status'));
+        $this->assertNotEmpty(data_get($asset->meta, 'checksum_verified_at'));
+        Storage::disk('archive-disk')->assertExists($path);
+        Storage::disk('hot-disk')->assertMissing($path);
+    }
+
+    public function test_marks_asset_failed_on_checksum_mismatch(): void
+    {
+        Storage::fake('hot-disk');
+        Storage::fake('archive-disk');
+
+        $hotTarget = MediaStorageTarget::create([
+            'key' => 'hot-disk',
+            'name' => 'Hot Disk',
+            'driver' => 'local',
+            'config' => [],
+            'is_hot' => true,
+            'is_default' => true,
+            'is_active' => true,
+            'priority' => 100,
+        ]);
+
+        MediaStorageTarget::create([
+            'key' => 'archive-disk',
+            'name' => 'Archive Disk',
+            'driver' => 'local',
+            'config' => [],
+            'is_hot' => false,
+            'is_default' => true,
+            'is_active' => true,
+            'priority' => 100,
+        ]);
+
+        $event = Event::factory()->create();
+        $path = 'events/'.$event->id.'/photo.jpg';
+        Storage::disk('hot-disk')->put($path, 'photo-body');
+
+        $asset = EventMediaAsset::create([
+            'event_id' => $event->id,
+            'media_storage_target_id' => $hotTarget->id,
+            'photo_id' => null,
+            'variant' => 'original',
+            'disk' => 'hot-disk',
+            'path' => $path,
+            'size_bytes' => 10,
+            'checksum' => hash('sha256', 'different-body'),
+            'status' => 'hot',
+        ]);
+
+        (new ArchiveEventMediaAssets($event->id, true))->handle(app(EventStorageManager::class));
+
+        $asset->refresh();
+
+        $this->assertSame('failed', $asset->status);
+        $this->assertSame('checksum_mismatch', $asset->error_message);
+        $this->assertSame('mismatch', data_get($asset->meta, 'checksum_status'));
+        $this->assertSame('hot-disk', $asset->disk);
+        Storage::disk('hot-disk')->assertExists($path);
+        Storage::disk('archive-disk')->assertMissing($path);
+    }
+}
diff --git a/tests/Feature/Console/MonitorStorageCommandTest.php b/tests/Feature/Console/MonitorStorageCommandTest.php
index c76af3a..7763103 100644
--- a/tests/Feature/Console/MonitorStorageCommandTest.php
+++ b/tests/Feature/Console/MonitorStorageCommandTest.php
@@ -75,4 +75,62 @@ class MonitorStorageCommandTest extends TestCase
         $this->assertSame(2, $snapshot['targets'][0]['assets']['total']);
         $this->assertGreaterThanOrEqual(1, count($snapshot['alerts']));
     }
+
+    public function test_monitor_command_flags_checksum_mismatches(): void
+    {
+        config([
+            'storage-monitor.checksum_validation.enabled' => true,
+            'storage-monitor.checksum_validation.alert_window_minutes' => 60,
+            'storage-monitor.checksum_validation.thresholds.warning' => 1,
+            'storage-monitor.checksum_validation.thresholds.critical' => 5,
+        ]);
+
+        $target = MediaStorageTarget::create([
+            'key' => 'local-ssd',
+            'name' => 'Local SSD',
+            'driver' => 'local',
+            'config' => ['monitor_path' => storage_path('app')],
+            'is_hot' => true,
+            'is_default' => true,
+            'is_active' => true,
+            'priority' => 100,
+        ]);
+
+        $event = Event::factory()->create();
+
+        EventMediaAsset::create([
+            'event_id' => $event->id,
+            'media_storage_target_id' => $target->id,
+            'photo_id' => null,
+            'variant' => 'original',
+            'disk' => 'local-ssd',
+            'path' => 'events/'.$event->id.'/photo.jpg',
+            'size_bytes' => 2048,
+            'status' => 'failed',
+            'meta' => [
+                'checksum_status' => 'mismatch',
+                'checksum_verified_at' => now()->toIso8601String(),
+            ],
+        ]);
+
+        $health = Mockery::mock(StorageHealthService::class);
+        $health->shouldReceive('getCapacity')->andReturn([
+            'status' => 'ok',
+            'total' => 100,
+            'free' => 90,
+            'used' => 10,
+            'percentage' => 10,
+            'path' => storage_path('app'),
+        ]);
+        $this->app->instance(StorageHealthService::class, $health);
+
+        $this->artisan('storage:monitor')
+            ->assertExitCode(0);
+
+        $snapshot = Cache::get('storage:monitor:last');
+
+        $this->assertNotNull($snapshot);
+        $alerts = collect($snapshot['alerts'] ?? []);
+        $this->assertTrue($alerts->contains(fn ($alert) => ($alert['type'] ?? null) === 'checksum_mismatch'));
+    }
 }