You are quite wrong.
Data in RAM
Data remanence has been observed in
static random-access memory (SRAM), which is typically considered volatile (
i.e., the contents degrade with loss of external power). In one study, data retention was observed even at room temperature.
[11]
Data remanence has also been observed in
dynamic random-access memory (DRAM). Modern DRAM chips have a built-in self-refresh module, as they not only require a power supply to retain data, but must also be periodically refreshed to prevent their data contents from fading away from the capacitors in their integrated circuits. A study found data remanence in DRAM with data retention of seconds to minutes at room temperature and "a full week without refresh when cooled with liquid nitrogen."
[12] The study authors were able to use a
cold boot attack to recover cryptographic
keys for several popular
full disk encryption systems, including Microsoft
BitLocker, Apple
FileVault,
dm-crypt for Linux, and
TrueCrypt.
[12](p12)
Despite some memory degradation, authors of the above described study were able to take advantage of redundancy in the way keys are stored after they have been expanded for efficient use, such as in
key scheduling. The authors recommend that computers be powered down, rather than be left in a "
sleep" state, when not in physical control of the owner. In some cases, such as certain modes of the software program BitLocker, the authors recommend that a boot password or a key on a removable USB device be used.
[12](p12)
TRESOR is a
kernel patch for Linux specifically intended to prevent
cold boot attacks on RAM by ensuring encryption keys are neither user accessible nor stored in RAM.
