Electronically filed tax returns and accountancy documentation must be encrypted and signed electronically. For security reasons the cryptographic protection of information (CIPF) is used. This is a set of hardware and software (encryption and qualified electronic signature) that ensure the protection of information with support of approved cryptography standards and certified by law.
The use of qualified electronic signature (QES) of the document and CIPF provides:
Confidentiality - to protect taxpayer’s identity or data from being read;
Authentication - to ensure that filed reports originate from a particular taxpayer;
Data integrity - to protect the report files from unauthorized changes.
Data encryption equipment used in e-filing is similar to encryption systems of law enforcement authorities, intelligence services, banks, etc.
Thus, the e-filing tax returns and accounting documentation are fully protected from unauthorized changes. Only the tax authority has the capability to read filed documents as it has the encryption keys to decrypt the message.