Intercept data today and decipher it tomorrow - quantum makes this strategy even more enticing

Attackers cleverly exploit the need for long-term data protection. Quantum computers amplify the likelihood of a "Harvest Now Decrypt Later" attack success.

Data has a lifespan—sometimes stretching decades in the case of commercial secrets or research results. Consequently, the data must be protected for its entire life cycle.

A notable technique to exploit the longevity of the data is the "Harvest Now, Decrypt Later" attack. This strategy involves capturing and storing encrypted data, with the intent to decrypt it before it becomes obsolete. This could be due to advancements in computational power or the emergence of a novel mathematical method capable of breaking the encryption. Such an expectation isn't unfounded, given that current cryptographic methods rely on computational complexity assumptions. These are merely assumptions without rigorous proof, implying that some problems are very hard to solve.

Here's how the attack unfolds:

Initially, a document is encrypted, presumably ensuring its security. But what if current cryptographic methods don't guarantee security throughout the document's lifecycle? Operating on this premise, an attacker might intercept a document, be it a database backup, a virtual machine dump, or a ten-day stream of confidential file uploads. However, not all data is targeted. Since every attack needs to be cost-effective, attackers will likely prioritise intercepting large, structured datasets encrypted with a single key. But as the cost of initiating these attacks reduces, even smaller data sets might become vulnerable.

After interception, the attacker retains the document in its encrypted state. The underlying hope is for advancements in computational capabilities or the introduction of a groundbreaking mathematical method that will enable decryption before the data's value diminishes. If such a scenario unfolds, the attack is deemed successful.

One might question the influence of quantum computers in this scenario. While the "Harvest Now, Decrypt Later" tactic predated the rise of quantum computing, the essence of the attack is the anticipation of evolving decryption tools. Quantum computers epitomize this evolution, amplifying the likelihood of the attack's success.

Two characteristics distinguish the "Harvest Now, Decrypt Later" strategy from other cyber threats. For one, it's exceedingly difficult to identify. Think about someone just sniffing traffic directed at a specific application. Furthermore, in its culmination, it is impossible to stop attackers. Once data is lost, it is lost. This contrasts with contemporary practices where, following a breach, tools exist to mitigate further damage.