When a digital signature is generated, the signer does not incorporate in the document evidences that give the probative value of this signature. This digital evidence is picked up automatically during the verification process for each digital signature. For performing later verifications of the signatures, such evidences will be stored as fundamental data, that later can be extracted and used by third parties, as probative elements.

Service oriented architectures offer a fast and easy deployment method to add new functionalities to existing applications. In particular, digital signature generation and validation web services, offered in this site, can be used into the processing of commonly used formats of electronic invoices.

Article "How to sign using locally stored certificates (OpenSignX)" of this website introduced Safelayer's OpenSignX Java applet that is capable of electronically signing web forms and documents on top of several platforms and web browsers. The applet produces a basic Electronic Signature (enveloping XAdES format) using X.509v3 certificates (i.e. Spanish ID card "DNI electrónico", Verisign, Spanish Royal Mint "CERES-FNMT").

Every day  the amount of procedures and transactions that are offered on the Web grows more and more. They require users to electronically sign using certificates installed on their browsers or in smart-cards. Currently there is no widely used or standardized solution.