Billing by fax/e-mail

Since November 2006 we have been sending invoices to customers via fax and e-mail.

From a legal perspective there is no cause for concern due to a "qualified electronic signature"

(see Bulletin of the German Federal Ministry of Finance dated 29.01.2004).

At first glance it seems unusual, the invoice has a gray matrix filed in the lower third (2D-barcode). This field contains the encoded original data, the certificate associated with it (electronic ID) and the qualified electronic signature, with which you can check the authenticity of the invoice. The issuer of the certificate is D-Trust GmbH, a 100% subsidiary of the German Deutschen Bundespressureerei (

The qualified electronic signature is prescribed in the following cases:

-Invoicing sent via e-mail

-Invoicing sent via fax, if it is certain that this transmission proceeds from a standard fax machine to a standard fax machine


The major advantage of both types of sending:

The signature barcode is directly applied to the invoice. This is a new development from the companies Eviatec Systems AG of Ludwigsburg ( and Secrypt GmbH of Berlin ( This innovative solution has already drawn great and very positive attention from the general public.


Sample Invoice:




But how can you, as the recipient of an electronic document, trust that the document’s content and form remain unaltered, exactly as the sender sent it? And how secure is the sender’s identity?

Traditionally, these functions are performed by the manual signature, which documents a statement of the signer’s intentions and demonstrates his/her identity. The electronic signature plays the role of a handwritten signature in electronic transactions.

The electronic signature makes it possible to check whether the contents have been altered after it was signed or not; it also allows for clear identification of the party who signed the data.

Due to these quality criteria, the legislatures in the EU have allotted the “qualified electronic signature” a legally binding character.

On the Legal Force of an Electronic Signature

Every declaration of intent that meets the usual legal preconditions (legal competence, etc.) and is not subject to a particular formal requirement is legally valid. In the framework of open consideration of evidence, its physical manifestation, e.g. as an e-mail, is admissible before a court.

The declaration of intent that is accompanied by a "qualified electronic signature" under the German Signature Act also meets the formal requirement of “legal written form” under certain conditions and has the status of “prima facie evidence” before a court.



Under §§126ff BGB (German Civil Code), the legal "qualified electronic signature" is considered equivalent to a hand-written signature in legal written form under private law if the signed document is supplemented with the name of the signing party (“electronic form”) and this electronic form is not explicitly prohibited under law. Such an exclusion applies at this time to the termination and modification of employment relationships (§623 BGB), the issue of performance reviews (§630 BGB) as well as life annuity guarantees (§761 BGB), declarations of surety (§766 BGB), promises (§780 BGB) and statements of recognition (§781 BGB).


Evidentiary Force:

Under §282a ZPO (German Code of Civil Procedure), a signature in electronic form is considered “apparently authentic” under §126 BGB, if a test under the signature act produces this result. This means that in cases of doubt before a court, it is not the authenticity of the signature that must be proved, but that serious doubts about the authenticity of this signature must be presented with facts, if the signature is shown to be authentic by signature software that conforms to legal requirements.


Test of the Signature:

Unusual at first glance, there is a gray matrix field (2D-bar code) in the lower third of every invoice from Mink-Brushes. This field contains the encoded original data, the certificate associated with it (electronic ID) and the qualified electronic signature, with which you can check the authenticity of the invoice.





Download the free testing programme digiSeal reader and install it

Scan the invoice if it is not already available in digital format: BMP, 300dpi, gray scale.


Test the invoice. Now the original document from which the 2D-bar code was generated and the matching signature will be automatically displayed.



Open the invoice as a file in the format BMP, 300dpi, gray scale or scan the record directly using the digiSeal reader.



The signature of the original document generated from the 2D-bar code will now be displayed. Using the function you can display the content of the certificate.



Using the function, the content of the bar code can be compared with the text area in the invoice.



You can get more information on the electronic signature as well as the digiSeal reader at To view our order confirmations and delivery notes you need the Adobe Reader; to test our invoices use the digiSeal reader.




Free Downloads:




(Text and explanation with the kind permission of Mink KG, Göppingen)




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