An Garda Síochána has said Commissioner Nóirín O'Sullivan is aware of her obligations to protect national security and would not compromise it under any circumstances.
The claim is part of a statement defending Commissioner O'Sullivan's "occasional" use of Gmail for official business.
Yesterday's Sunday Times reported the email was linked to a Dropbox account that was hacked in 2012.
Today, the Gardaí said the Commissioner's devices have secure connections and utilise strong encryption technologies.
It also claimed the Commissioner needs to use her own email as the Garda system does not have sufficient email size or storage.
Commissioner O'Sullivan will shortly submit a report on the matter to the Department of Justice and the Policing Authority.