diff --git a/migrations/Version20260321230000.php b/migrations/Version20260321230000.php
new file mode 100644
index 0000000..1ee917b
--- /dev/null
+++ b/migrations/Version20260321230000.php
@@ -0,0 +1,26 @@
+<?php
+
+declare(strict_types=1);
+
+namespace DoctrineMigrations;
+
+use Doctrine\DBAL\Schema\Schema;
+use Doctrine\Migrations\AbstractMigration;
+
+final class Version20260321230000 extends AbstractMigration
+{
+    public function getDescription(): string
+    {
+        return 'Add security_key to billet_order';
+    }
+
+    public function up(Schema $schema): void
+    {
+        $this->addSql("ALTER TABLE billet_order ADD COLUMN IF NOT EXISTS security_key VARCHAR(16) DEFAULT '' NOT NULL");
+    }
+
+    public function down(Schema $schema): void
+    {
+        $this->addSql('ALTER TABLE billet_order DROP COLUMN IF EXISTS security_key');
+    }
+}
diff --git a/src/Entity/BilletOrder.php b/src/Entity/BilletOrder.php
index f28151a..ca27ef7 100644
--- a/src/Entity/BilletOrder.php
+++ b/src/Entity/BilletOrder.php
@@ -27,6 +27,9 @@ class BilletOrder
     #[ORM\Column(length: 255)]
     private ?string $billetName = null;
 
+    #[ORM\Column(length: 16)]
+    private string $securityKey = '';
+
     #[ORM\Column]
     private int $unitPriceHT = 0;
 
@@ -98,6 +101,23 @@ class BilletOrder
         return $this;
     }
 
+    public function getSecurityKey(): string
+    {
+        return $this->securityKey;
+    }
+
+    public function setSecurityKey(string $securityKey): static
+    {
+        $this->securityKey = $securityKey;
+
+        return $this;
+    }
+
+    public static function generateSecurityKey(string $reference, string $appSecret): string
+    {
+        return strtoupper(substr(hash_hmac('sha256', $reference, $appSecret), 0, 16));
+    }
+
     public function getUnitPriceHT(): int
     {
         return $this->unitPriceHT;
diff --git a/src/Service/BilletOrderService.php b/src/Service/BilletOrderService.php
index 3876d70..c367c44 100644
--- a/src/Service/BilletOrderService.php
+++ b/src/Service/BilletOrderService.php
@@ -25,6 +25,7 @@ class BilletOrderService
         private MailerService $mailer,
         private UrlGeneratorInterface $urlGenerator,
         #[Autowire('%kernel.project_dir%')] private string $projectDir,
+        #[Autowire('%kernel.secret%')] private string $appSecret,
     ) {
     }
 
@@ -37,6 +38,7 @@ class BilletOrderService
                 $ticket->setBillet($item->getBillet());
                 $ticket->setBilletName($item->getBilletName());
                 $ticket->setUnitPriceHT($item->getUnitPriceHT());
+                $ticket->setSecurityKey(BilletOrder::generateSecurityKey($ticket->getReference(), $this->appSecret));
 
                 $this->em->persist($ticket);
             }
diff --git a/templates/pdf/billet.html.twig b/templates/pdf/billet.html.twig
index 845c0d5..948a70f 100644
--- a/templates/pdf/billet.html.twig
+++ b/templates/pdf/billet.html.twig
@@ -306,6 +306,7 @@
                         <tr>
                             <td style="width: 140px;">
                                 <img src="{{ qrBase64 }}" alt="QR" class="qr-img">
+                                <div style="font-size: 6px; font-weight: bold; text-align: center; color: #999; margin-top: 4px; text-transform: uppercase;">Presentez ce QR code<br>pour valider votre ticket</div>
                             </td>
                             <td style="text-align: right;">
                                 <div class="ref-lbl">Reference billet</div>
@@ -313,6 +314,9 @@
                                 <br>
                                 <div class="ref-lbl">Commande</div>
                                 <div class="ref-val">{{ order.orderNumber }}</div>
+                                <br>
+                                <div class="ref-lbl">Cle de securite</div>
+                                <div class="ref-val" style="letter-spacing: 2px;">{{ ticket.securityKey }}</div>
                             </td>
                         </tr>
                     </table>
diff --git a/tests/Entity/BilletOrderTest.php b/tests/Entity/BilletOrderTest.php
index 3b006c8..e54343a 100644
--- a/tests/Entity/BilletOrderTest.php
+++ b/tests/Entity/BilletOrderTest.php
@@ -21,6 +21,7 @@ class BilletOrderTest extends TestCase
         self::assertSame(0.0, $ticket->getUnitPriceHTDecimal());
         self::assertSame(BilletOrder::STATE_VALID, $ticket->getState());
         self::assertTrue($ticket->isValid());
+        self::assertSame('', $ticket->getSecurityKey());
         self::assertNull($ticket->isInvitation());
         self::assertNull($ticket->getFirstScannedAt());
         self::assertMatchesRegularExpression('/^ETICKET-[A-Z0-9]{4}-[A-Z0-9]{4}-[A-Z0-9]{4}$/', $ticket->getReference());
@@ -83,6 +84,29 @@ class BilletOrderTest extends TestCase
         self::assertTrue($ticket->isValid());
     }
 
+    public function testSetAndGetSecurityKey(): void
+    {
+        $ticket = new BilletOrder();
+        $result = $ticket->setSecurityKey('ABC123');
+
+        self::assertSame('ABC123', $ticket->getSecurityKey());
+        self::assertSame($ticket, $result);
+    }
+
+    public function testGenerateSecurityKey(): void
+    {
+        $key = BilletOrder::generateSecurityKey('ETICKET-ABCD-1234-EFGH', 'my-secret');
+
+        self::assertSame(16, \strlen($key));
+        self::assertMatchesRegularExpression('/^[A-F0-9]{16}$/', $key);
+
+        $key2 = BilletOrder::generateSecurityKey('ETICKET-ABCD-1234-EFGH', 'my-secret');
+        self::assertSame($key, $key2);
+
+        $key3 = BilletOrder::generateSecurityKey('ETICKET-XXXX-YYYY-ZZZZ', 'my-secret');
+        self::assertNotSame($key, $key3);
+    }
+
     public function testSetAndGetIsInvitation(): void
     {
         $ticket = new BilletOrder();