A method to generate Immutable Audit logs (IAL) using related computer means and/or computer programs. This method and system processes audit information by cryptographic means generating one immutable digital chains that will contain at least the audit information split among the links and optionally encrypted, and this immutable digital chain is stored in a massive storage media. Each immutable digital chain is generated by including at every link at least the data resulting to apply a MAC function using a secret session key K over the result of information at current link concatenated with a previous link MAC value. The method proposes adding specific links to said immutable digital chain at regular defined intervals (‘Metronome Entry’) that contain at least a timestamp and the data resulting to apply a digital signature using a private key that is always kept secret over the metronome timestamp concatenated with previous link results.