The President-elect also stated that couriers should be used instead of computers
Donald Trump has refuted claims that Russia was involved in hacking which may have influenced the outcome of the Presidential election in November.
In October, the US government formally accused Russia of cyberattacks, while President Obama ordered a review by intelligence agencies into interference in the election.
Earlier this week, President Obama announced that the United States would expel 35 Russian diplomats in response to the interference as well as the "harassment" of American diplomats in Moscow.
Speaking ahead of his New Year's Eve party in the Mar-a-Lago resort, Trump denied Russian involvement and questioned the findings of the US intelligence agencies, saying that he needed to be sure that they were correct.
"If you look at the weapons of mass destruction, that was a disaster, and they were wrong," the Preisdent-elect told a pool of reporters.
"Hacking is a very hard thing to prove," added Trump, "so it could be somebody else. And I also know things that other people don’t know, and so they cannot be sure of the situation."
Pressed to reveal what information he had that was pertinent to the story, Mr Trump refused, adding: "You’ll find out on Tuesday or Wednesday."
He also expressed concerns over the safety of digital communications of any sort, stating that: "I don't care what they say. No computer is safe."
He added that messages and important information should be sent by courier: "You know, if you have something really important, write it out and have it delivered by courier, the old-fashioned way."