Digital Signature Service - DSS

What is DSS?

Purpose of the service

DSS (Digital Signature Services) is an open-source software library for electronic signature creation and validation. DSS supports the creation and verification of interoperable and secure electronic signatures in line with European legislation. In particular, DSS aims to follow the eIDAS Regulation and related standards closely.

DSS can be re-used in an IT solution for electronic signatures to ensure that signatures are created and verified in line with European legislation and standards. DSS allows re-use in a variety of different ways: in an applet, in a stand-alone application or in a server application. DSS can also be used as a reference implementation for IT solutions which do not directly re-use it. Demos are also available to assist the use of DSS as a reference implementation. DSS was developed by Nowina Solutions and is maintained up-to-date via new releases.

Users of the service

The Digital Europe eSignature DSS service is intended for Service Providers active in the implementation of e-signature solutions.

Benefits of the service 

Digital Europe eSignature's DSS open-source library delivers the following benefits to its users:

• Open-source software under LGPL 2.1, a non-viral open source license;
• Written in Java, guaranteeing portability on numerous platforms;
• Interoperability of the e-signatures;
• Supports both e-signatures and e-seals;
• Validation of countersignatures and multiple signatures;
• A flexible library, that can be:
  • Reused in different topologies: in an applet, as a stand-alone application, server-based, or any combination;
  • Used in its entirety or on a module-by-module basis;
  • Adapted to numerous usages via configuration files or extension points;
• Alignment with the eIDAS Regulation and related standards;
• Supports EU standards on:
  • Signature formats and packaging methods;
  • Signature validation procedures;
• Validation relying on Member States' trusted lists:
  • Status of trust service providers/trust service, compensation of information, path validation.

How can it be used?

The library, realised in Java, is open-source, available to all Member States, businesses and citizens for re-use in electronic signature solutions. It is continuously updated and maintained to anticipate and follow developments in regulations and standards. 

Anyone can integrate it and redistribute it under the terms of the Lesser General Public License (LGPL 2.1).

In accordance with ETSI standards, DSS supports various document and signature formats including PAdES, XAdES, CAdES and ASiC and is compliant with Implementing Decision 2015/1506/EU. A “cook-book” is also provided with documentation targeting implementers/developers and aiming at facilitating the integration and use of DSS in their applications.

Validation of qualified and advanced signatures and seals

In anticipation of the ETSI standard, TS 119 172-4, which is currently being drafted with the aim of standardising a “signature validation policy for European qualified electronic signatures/seals using trusted lists”, eSignature Building Block’s provides its interpretation of the eIDAS Regulation's requirements for the validation of qualified and advanced signatures and seals.

This algorithm has been designed following discussions and meetings with experts involved in the field, in the context of the Digital Europe eSignature Building Block. This algorithm is to be considered as guidelines for implementers, or parties interested in understanding how QES validation is implemented in DSS.

The algorithm (available below) focuses on determining 3 sub-conclusions:

- Whether the certificate is qualified

- What is the type of this certificate

- Whether the corresponding private key is protected by a QSCD.

Demonstration tool

Demos of DSS for electronic signature creation, extension and validation

The Digital Europe eSignature building block maintains a demonstration tool that allows everybody interested in the DSS functionalities to try them out.

The demo tool is a web application that, among others, allows users to:

• upload and sign a document
• upload and sign multiple documents
• access REST / SOAP webservices 
• extend an electronic signature
• validate an electronic signature

Releases and Bitbucket

DSS releases are part of the eSignature service offering. 

The Digital Europe eSignature building block collects all issues, bugs, or requests for change in the DSS project's JIRA. More information on how to use JIRA can be found here. 

Source code is also made available on the DSS Bitbucket repository.  

Please note that, due a Joinup migration, older versions of DSS need to be adapted in order to compile successfully. Practical details can be found here.

Documentation

Documentation is available in HTML, PDF and Javadoc.

Releases

Summary of current version

Bug

• [DSS-2513] - Certificates embedded into an OCSP response are not timestamped
• [DSS-2515] - JAdES : avoid exception on a detached LTA signature validation without original file
• [DSS-2522] - Unable to augment ASiC-E with CAdES LTA with expired signing certificate
• [DSS-2524] - JAdES : tstVD certificates are not reported within FoundCertificates
• [DSS-2526] - TL-Summary webPage : rows recalculated on a collapse
• [DSS-2530] - JAdES ValidationReport with multiple tstVD
• [DSS-2534] - SVC : check revocation data is known to contain information about certificate
• [DSS-2539] - JAdES : a new added signature with a higher level extends other signatures
• [DSS-2540] - PdfBox : cast exception when signing non-signature field
• [DSS-2545] - Wrong minimal key size for DSA in default validation policy
• [DSS-2547] - WebApp : unable to sign when the used encryption algorithm is different from the one used to sign the certificate
• [DSS-2551] - Revocation data is not acceptable warning is reported on LTV process when a valid revocation is available
• [DSS-2560] - Custom TokenIdentifierProvider duplicates SignerData objects in DiagnosticData

Improvement

• [DSS-2479] - SVG timeline : add support for independent timestamps validation
• [DSS-2518] - Deadlocks on TLAnalysis if analysis throws exception
• [DSS-2535] - WebApp : add dataLoader timeout configuration to properties file
• [DSS-2549] - WebApp : log exception stacktrace

Past releases

Security information

Following a security assessment from the Ruhr-Universität Bochum, we are delivering security patches for DSS versions 5.2 and 5.3.

Delivered patches are:

• 5.2 → 5.2.1
• 5.3.0 / 5.3.1 → 5.3.2

  Please consider that use of older versions should be discouraged.  

 XAdES / ASiC with XAdES / TL-based signature validation

If your DSS integration is using XAdES, ASiC with XAdES, or TL-based signature validation, it is strongly encouraged to upgrade your version.

The patches enforce signature validations against different kinds of attack: XML Signature Wrapping (XSW), XPath injections, Server Side Request Forgeries (SSRF) and XML External Entities (XEE).

While upgrading, be sure that your integration :

• doesn't use Xalan or XercesImpl dependencies
• uses a patched Java version (JDK7u40+, JDK8 or higher)

PAdES

If you use dss-pades, it is also strongly encouraged to upgrade your DSS version, as these releases include a fix of PdfBox to patch vulnerabilities.

Contribute

If you would like to speak to us about suggested improvement for Digital Europe eSignature, we would love to hear from you. Please contact us by clicking on the button below.

Contact us

Click here to see the DSS Jira project's current issue list.