A research team at Princeton University has found a method to break into an encrypted hard drive to access protected information.

The method involves freezing the DRAM or Dynamic Random Access Memory in a computer. Freezing the memory can be easily done by spraying the memory chips with the cold canned air found in duster spray. Researchers said in a report published on Thursday that doing this, allows the chip to retain data for minutes or even hours after the computer is out of power.

Software used to encrypt hard drive information stores security keys in the computer's DRAM memory. After freezing the chip, Hackers are able to access the key information by restarting the computer and copying the memory contents with a simple program. The keys can then be used to access the hard drive.

Ultimately, it might become necessary to treat DRAM as untrusted, and to avoid storing sensitive confidential data there, but this will not be feasible until architectures are changed to give software a safe place to keep its keys, wrote the researchers in the report.

The report was published on Thursday was by researchers at Princeton, the Electronic Frontier Foundation digital rights group, and Wind River Systems software company.

Although researchers affirmed that it was known since the 1970s that the memory chips could retain information when the DRAM is frozen, they said this study is the first security paper to focus on the phenomenon.