On the basis of the principles of integrity, authenticity, confidentiality non rejection and has built a significant infrastructure getting provide all these added values to electronic communications.

Thus, security viewed from a technical level is given by the asymmetrical key cryptography applied to the electronic signature of documents.

There is another level, the legal, with the necessary security. In the case of Spain is guaranteed by the Law 6 / 2020 , 11 november, which regulates certain aspects of electronic services, which repealed the law 59 / 2003 , 19 december, of electronic signature and regulation (EU) No 910 / 2014 of the european parliament and of the security council 23 july 2014 on the electronic identification and confidence to electronic transactions in the internal market and repealing Directive 1999 / 93 EC.

The Regulation (EU) 910 / 2014 of the european parliament and of the security council 23 july 2014 the electronic signature distinguishing three kinds:

• The electronic signature, are “ data in electronic form annexed to other electronic data or logically associated with them to use the signatory for the purpose of signing ”.
• The advanced electronic signature is "the electronic signature is linked to the signatory singly, identifying the signatory, which has been created using data of creating an electronic signature that the author can, with a high level of confidence, within its exclusive control and is linked with signed data for the same fashion such that any modification thereof is detectable. ”
• The electronic signature is a qualified “ advanced electronic signature created by a qualified, creation of electronic signatures and that is based on a qualified certificate of electronic signature ”. An electronic signature will have a qualified legal effect equivalent to that of a handwritten signature.

The legislation in force on electronic signatures at european level and state levels is as follows:

• At european level:
  • Regulation (EU) 910 / 2014 of the european parliament and of the security council 23 july 2014 on the electronic identification and confidence to electronic transactions in the internal market and repealing Directive 1999 / 93 /EC.
  • Directive 2000 / 31 /Ec of the european parliament and the council, 8 june 2000 on certain legal aspects of the information society services, including e-commerce in the internal market (Directive on electronic commerce).
  • Regulation (EU) 2016 / 679 of the european parliament and of the security council 27 april 2016 on the protection of individuals with regard to the treatment of personal data and the free movement of such data and repealing directive 95 / 46 /EC.

• At the state level:
  • Law 59 / 2003 , 19 december, of electronic signature.
  • Law 34 / 2002 , 11 july, of the information society and electronic commerce.
  • Law 56 / 2007 , 28 major emphasis of the information society.
  • Organization Act 3 / 2018 , 5 december on Personal data protection and guarantee of the digital rights.