diff --git a/src/Entity/UserSystem/U2FKey.php b/src/Entity/UserSystem/U2FKey.php
index 151fa980..f9dd301f 100644
--- a/src/Entity/UserSystem/U2FKey.php
+++ b/src/Entity/UserSystem/U2FKey.php
@@ -59,15 +59,15 @@ class U2FKey implements TwoFactorKeyInterface
     use TimestampTrait;
 
     /**
-     * @ORM\Column(type="string", length=64)
-     *
+     * We have to restrict the length here, as InnoDB only supports key index with max. 767 Bytes.
+     * Max length of keyhandles should be 128. (According to U2F_MAX_KH_SIZE in FIDO example C code).
+     * @ORM\Column(type="string", length=128)
      * @var string
      **/
     public $keyHandle;
 
     /**
      * @ORM\Column(type="string")
-     *
      * @var string
      **/
     public $publicKey;
diff --git a/src/Migrations/Version20200409130946.php b/src/Migrations/Version20200409130946.php
new file mode 100644
index 00000000..64bf246f
--- /dev/null
+++ b/src/Migrations/Version20200409130946.php
@@ -0,0 +1,35 @@
+<?php
+
+declare(strict_types=1);
+
+namespace DoctrineMigrations;
+
+use Doctrine\DBAL\Schema\Schema;
+use Doctrine\Migrations\AbstractMigration;
+
+/**
+ * Auto-generated Migration: Please modify to your needs!
+ */
+final class Version20200409130946 extends AbstractMigration
+{
+    public function getDescription() : string
+    {
+        return '';
+    }
+
+    public function up(Schema $schema) : void
+    {
+        // this up() migration is auto-generated, please modify it to your needs
+        $this->abortIf($this->connection->getDatabasePlatform()->getName() !== 'mysql', 'Migration can only be executed safely on \'mysql\'.');
+
+        $this->addSql('ALTER TABLE u2f_keys CHANGE key_handle key_handle VARCHAR(128) NOT NULL');
+    }
+
+    public function down(Schema $schema) : void
+    {
+        // this down() migration is auto-generated, please modify it to your needs
+        $this->abortIf($this->connection->getDatabasePlatform()->getName() !== 'mysql', 'Migration can only be executed safely on \'mysql\'.');
+
+        $this->addSql('ALTER TABLE u2f_keys CHANGE key_handle key_handle VARCHAR(64) CHARACTER SET utf8mb4 NOT NULL COLLATE `utf8mb4_unicode_ci`');
+    }
+}