ADSS Go>Sign Service


ADSS Go>Sign Service is a complete solution for browser-based document viewing, signing and verification.  It also provides advanced functionality such as PDF conversion, PDF form-filling, PKI key generation, certificate request handling and secure document upload.  ADSS Go>Sign Service consists of server-side logic, a small but powerful applet and an optimised HTML document viewer.

The following highlights just some of its main features. 

Ease of use

  • Full control over the user experience
    The web application developer has complete control over the look and feel of the ADSS Go>Sign Applet user interface. Ascertia provides sample source code web pages to show how a solution can quickly be deployed. The aim is to use language that are meaningful to the business and the end-user and eliminate confusing technical terms.
  • Controls signing location
    Often users do not know where to sign the document and end up signing in the wrong page or wrong place. The use of digital signature fields helps but even so sometimes users will sign in a field assigned for another party. ADSS Go>Sign Applet caters for these by guiding users which fields they must sign and also prevent them from signing in the wrong place. Where flexibility is needed ADSS Go>Sign Applet allows user to create the signing field anywhere they desire.
  • Enables greater trust
    In many cases business managers and citizens do not know how to choose the correct certificate for signing and do not wish to be asked to do this. Configurations can be used to instruct ADSS Go>Sign Applet to look for a specific certificate based on signer’s name, issuer name, key usage, policy or other criteria and thus select the right certificate automatically without involving the end-user. The application can retrieve details of the selected certificate to show to the user. It may also need to show messages such as ‘insert your eID card’ where no certificate exists.

Digital signature formats

  • Standard digital signature formats
    ADSS Go>Sign Applet supports the creation and verification of all basic and advanced digital signature formats according to PDF, CMS/PKCS#7, XML DSig and all ETSI CAdES, XAdES and PAdES profiles.
  • What You See is What You Sign (WYSIWYS)
    A built-in document viewer displays PDF documents to users as a flattened image within an HTML page (documents in other format are converted to PDF on the fly by ADSS Server). The viewer is optimised for viewing even large documents efficiently by streaming the page images when required. 
  • Advanced PDF signature support
    ADSS Go>Sign Applet supports all the different kinds of PDF signatures including: visible and invisible signatures, certifying (author) signatures, approval signatures, Adobe® CDS signatures, PAdES signatures and PDF/A compliant signatures. Note long-term digital signature formats which include embedded timestamp and revocation information are created via calls to ADSS Go>Sign Service to provide this evidence information.  This ensures the Go>Sign Applet size remain smalls and the complexity is hidden both from the applet and the business web application.  

Documents support for PDF conversion

  • Document formats
    ADSS Go>Sign Applet supports the conversion of following document formats to PDF before signing: .doc, .docx, .xls, .xlsx, .ppt, .pptx, .odt, .sxw, .rtf, .txt, .ods, .csv and .tsv

Multiple document sources

  • Server supplied documents
    If the web application holds the document which needs signing then this can be supplied to the ADSS Go>Sign Service for local signing.
  • Local documents
    If the end-user locally holds the document then this can be located (or fed from web page using javascript) and then signed by ADSS Go>Sign Applet before uploading to the web application on the server.

Secure upload options

  • Secure document upload
    Often end-users not only need to sign but also secure their documents as part of an upload process e.g. as part of an e-tendering response submission process. To cater for this ADSS Go>Sign Applets allows the encryption of payload using the certificate supplied by the web application.

Easy integration

  • ADSS client SDK
    We have made integrating advanced trust services using ADSS Go>Sign Applet so simple with high-level HTTP calls. A Java and .NET SDK is also available to make the integration easy. These provide a very high-level API so you could be going in just a couple of lines of code. The SDKs also include plenty of source code samples and demo applications.
  • Rapid development and retro-fitting
    ADSS Go>Sign Service make it easy for developers to add digital signature generation and verification options to existing web pages and document workflows. All signing complexities are handled by these products using simple high level calls.
  • Reduced application complexity
    For visible PDF signatures ADSS Server manages the other complexities that include digital signature appearance, obtaining a timestamp, obtaining certificate chain status information. The PDF can also be Certified and locked. All these parameters are configured within signing profiles on the ADSS Server. When using the Go>Sign Viewer, users can draw digital signature fields. Where a digital signature field is shown the user can click within it to initiate digital signature generation. For greater control over trust the status of the digital signature is displayed based on ADSS Server decisions rather than local desktop trust decisions.

Multiple keystore options

  • Local digital signatures using smart card / USB tokens
    End-users can apply personal digital signatures using locally held smartcards, USB tokens or software keys. This is an ideal solution where users already hold smartcards/tokens e.g. as part of a national citizen eID infrastructure. ADSS Go>Sign Applet supports Windows® CAPI/CNG, PKCS#11 and Applet Keychain specifications for accessing keystores on Windows, MAC and UNIX systems.
  • Local digital signatures using roaming credentials
    ADSS Go>Sign Applet also provides an option to sign using roaming credentials. These are signing keys held within a secure container stored centrally by ADSS Server and delivered to user whenever required. User authentication is performed locally by ADSS Go>Sign Applet. A very flexible, low-cost and secure solution which provides ability to sign from any machine anywhere!
  • Unique user digital signatures on server
    Yet another ADSS Go>Sign Applet signing option is for the document to be hashed locally and then sent to the ADSS Server for signing. In this case the user’s keys are held securely on the ADSS Server within a secure HSM or encrypted database. This is very much like corporate digital signatures, but this time ADSS Server holds unique signing keys for ever user! The HSM (or encrypted database) acts a global smartcard for everyone, hence this concept is often referred to as a Virtual Smart Card. This approach has major cost and ease of use benefits than deploying smartcards/tokens to every user.

Centralised verification

  • Centralised verification
    There are issues with end-users verifying documents using locally-installed software including complexity in understanding, trust anchor management and no centralised control on verification policy as well as no centralised logging. For these reasons ADSS Go>Sign Service uses centralised verification services of ADSS Server.
  • Quality assessments
    ADSS Server not only provides cryptographic digital signature verification capability but also performs quality assessment of the Certificate Authority policy and practises, algorithm strengths and key lengths to get an overall idea of how trustworthy a particular digital signature is. ADSS Server follows the latest PEPPOL digital signature and certificate quality rating scheme. This quality assessment results can be delivered to ADSS Go>Sign Service. 

Data Leakage Prevention (DLP)

  • Securely deliver your documents
    Maintain control over documents and intellectual property by keeping them secure using the built-in security of ADSS Go>Sign Viewer. The web application can set the ADSS Go>Sign Viewer GUI by enabling/disabling functionality no a per user/document basis. Examples include ability to sign, ability to create blank digital signature fields, ability to print, ability to save document locally etc. The document is shown as an image file so preventing cut and paste of your sensitive information.
  • Get notification of delivery
    Another advantage of ADSS Go>Sign Viewer for document delivery is that it can prove that the document was seen by the user and if necessary also acknowledged.

Security & admin

  • Secure communication with server
    The ADSS Go>Sign Service communicates with the web application using a secure SSL/TLS connection for authentication, confidentiality and data integrity of information exchanged.
  • Applet digital signature
    The ADSS Go>Sign Applet is signed to ensure it is trusted by the browser.

Legal compliance

  • Legal compliance
    ADSS Go>Sign Applet and Service has been designed to be compliant with a range of digital signature legislation and regulatory frameworks, including EU law (EU Directive for Electronic Signatures), EU Directive for E-Invoicing, IdenTrust, US Electronic Signatures in Global and National Commerce Act (E-Sign), The Health Insurance Portability and Accountability Act (HIPAA), 21 CFR Part 11 (a regulation governing the use of electronic signatures within the pharmaceutical industry), Sarbanes-Oxley Act (SOX) and others. A configurable legal statement can be shown to the user before signing to ensure the user understands the implications of their digital signature.

Platform independence

  • Operating system independence
    ADSS Go>Sign is 100% JAVA applet and supported on Windows, Mac and Unix.
  • Smart card / secure USB token independence
    Any CAPI/CNG, Applet Keychain or PKCS#11 crypto device (i.e. smartcard or USB token) can work with ADSS Go>Sign Applet to sign documents.
  • Browser independence
    ADSS Go>Sign has been successfully tested on various browsers including Internet Explorer®, FireFox, Safari, Opera and Chrome.


  • Multi-lingual interface
    Localize the Go>Sign Viewer to any language and cater to your local audience. Change the full viewer look & feel or change the tooltips and text to any language.
  • Look and feel flexibility
    ADSS Go>Sign has been designed such that the user interface can be defined completely by the web application developer. Thus all communication with the user can be made in whatever terms are required to make it easy to use. For example a signing action button could be presented as a Sign or Confirm or Accept button in whichever local language is appropriate. Certificate selection and other interactions can be fully controlled by the application.
  • Tablets support
    Go>Sign supports WACOM STU-500 and SignoTec ST-ME105-2-FT-100 tablets.
  • Form filling support
    Go>Sign allows PDF forms filling.

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