Adobe Sign service functionality, in the "Enterprise Plan 2" version, enables senders to request signatories to use digital certificates. Anyone with a digital certificate and Acrobat Reader (or higher) properly configured on their device can thus be incorporated in an ad-hoc workflow via Sign Service. Signatories need not even have Sign Service licensed or installed on their devices.
Adobe Sign Service leaves certain "server processing marks" on documents handled via Sign Service that are not fully recognized by the public validation services for digitally signed documents in Switzerland (validator.ch).
Neither is the Adobe Sign service fully aware of validator.ch nor vice versa. As a result, documents with perfectly valid qualified digital signatures processed via Sign service appear to be invalid when checked against validator.ch criteria.
If you intend to use Adobe DC eSign Services to apply multiple diigital signatures to PDF documents based on qualified personal certificates, make sure
1. Make sure your IT really understands how Adobe Sign Service integrates with e-mail service.
2. If you use digital certificates via Sign service, Acrobat MUST be used as the system PDF viewer. The tight integration of Adobe Sign service with Acrobat is instrumental to how Sign service works with digital certificates.
3. Signatories must have properly configured browsers with up-to-date Adobe Acrobat PDF plugins in order for Sign service to work with digital certificates.
Signatories using end-user devices with Acrobat (at least Reader) and browsers properly configured will have no problem using Sign service with qualified personal digital certificates.
THE ADMIN IN CHARGE OF SIGNATORIES' DEVICES MUST KNOW:
The difference between a simple "electronically signed" and a legally compliant "digitally signed" PDF document is fundamental.
(Only) PDF documents signed with qualified digital certificates, such as SuisseID or equivalent national eIDs, are legally fully equivalent to paper documents with handwritten signatures. At least according to Swiss law (ZertES, OR) and respective laws in EU countries (eIDAS).
The compliance of any signed PDF document with Swiss signature law (ZertES), which requires the use of qualified certificates in combination in combination with certified time stamp servers, may be checked via the validator.ch service. This requires uploading (the hash of) a signed document to validator.ch and choosing one of several predefined standards against which to validate the document. Within a few seconds validator.ch will provide a detailed validation report in secured PDF format, which can be downloaded and used as evidence for the validity of the digitally signed document.
At the time of this review (Oct 2015) PDF documents digitally signed by multiple signatories using qualified personal certificates via Adobe DC eSign Services show certain "Adobe DC eSIgn server processing marks" which are not recognized by the standards defined in the current implementation of validator.ch..
Work is currently in progress to ensure that public validation services such as validator.ch adequately interpret the presence of such processing marks. The objective is for anyone to be able to check the validity of a digitally signed document against validator.ch (and similar national public service sites) and get instant verification for the validity of the signed electronic document in form of a downloadable validation report in secured PDF format.
The ease, speed and teacking of internal documents requiring formal approval by more than one person is greatly improved.
Senders can incorporate practically any recipient as a signatory. In principle, signatories need to have no more than a properly configured Adobe Reader (V9 or higher) and a qualified personal digital certificate (or equivalent signing service) in order to participate in business transactions via Sign service.
This dramatically shortens the time to complete the signing of documents by multiple signatories, particularly in business transactions involving geographically dispersed individuals from more than one organisation.
Benefits from digitally executing business transactions are mainly due to reductions in transaction cycle time and improvements in quality through document process monitoring and control.