The ADACOM qualified certificate with the usage of an SSCD (Secure Signature Creation Device) provides the highest level of guarantee since it supports the usage of digital signature equivalent to the physical signature in terms of legal effectiveness according to the Presidential Decree # 150/2001, EU/93/99 Directive, and the specifications in The Decision No.248/71 of the National Committee of Telecommunications & Post (EETT).

In parallel, the use of qualified digital certificates provides security, integrity and non-repudiation, critical attributes of an efficient communication through electronic means, since:

• They protect electronic messages from any counterfeiting and attempt of false impersonation and authentication.
• Add electronic signature as proof of identity.
• Encrypt messages and attached files to sageguard their contents from third party access.

How the electronic signature functions

The whole process of electronic signature is based on PKI, the puclic key infrastructure and assymetric cryptography techniques. Every subject that has at its disposal a qualified digital certificate has been awarded a couple of keys: a public key that can be widely referred to and distributed freely, and a private key, absolutely secret that resides at an SSCD (Secure Signature Creation Device).

A document will be signed with the public key of the recipient in such a manner that it can be decrypted only with its corresponding private key. In addition, one can electronically sign the document with its own private key in order to certify to the recipient the originallity of the message. These two processes can be combined together in order to guarantee simultaneously that the document's contents have been ensured and its origin has been substantiated.

All the major e-mail programs have integrated the function of electronic signature verification: a mechanism that is based on a hash algorithm that calculates the digital stamp of the text and is being compared to the corresponding hash algrithm that has been calculated and encrypted at the moment of sending.

ADACOM as a Certificate Authority

In order for the process of electronic signature to be considered legally valid it is necessary to ensure that any couple of keys (public and private) effectively corresponds to a well identified subject. This is accomplished through a Trusted Third Party. ADACOM as a Certificate Authority supervises the parties involved and guaranties their credibility undertaking all the responsibility for the life cycle of each individual certificate. In accordance with Greek and European law ADACOM has been registered at the National Committee of Telecommunications & Post (EETT), registry of Certification Services Providers for Qualified Certificates.