mobile.de has been signing its invoices with the legally compliant mass signature multisign solution since 2008. The company opted for the secunet multisign Service version. Invoices are signed at a data centre of the Deutsche Post and sent back to mobile.de. With support provided by phone by a secunet consultant, mobile.de completed the installation and configuration itself. Invoices were electronically signed and issued that very same day. The electronic signature entitles customers of mobile.de to deduct input tax.