Electronic billing with qualified digital signature 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 With support provided by phone by a secunet consultant, completed the installation and configuration itself. Invoices were electronically signed and issued that very same day. The electronic signature entitles customers of to deduct input tax.