Lava lamps for secure encryption

Lava lamps for secure encryption

The importance of randomness in secure encryption

Secure encryption depends on randomness. The encryption keys used to encrypt and decrypt data must therefore be unpredictable. This helps to thwart unauthorised decryption attempts. Predictability, however slight, in these keys can be exploited by attackers to gain access to sensitive information.

The limits of computer randomness

Computers, by nature, are designed for logic and predictability. Their ability to generate true randomness is therefore intrinsically limited. Computer programmes can only produce “pseudo-random”, which is insufficient for advanced cryptographic needs.

Lava lamps: an ingenious solution

To overcome these limitations, Cloudflare resorted to an original method: the use of lava lamps. These objects are not only popular for their psychedelic aesthetics. They are also ideal for generating randomness:

  • Unpredictability: The lava in these lamps forms constantly changing and unpredictable patterns.
  • Use as a data source: By capturing images of these lava lamps, Cloudflare creates a reliable source of random data.

The technical process

Cameras positioned in front of a wall of lava lamps at Cloudflare’s headquarters regularly capture images. Once digitised, these images are transformed into sequences of numbers representing each pixel. These sequences of numbers serve as random seeds for cryptographically secure pseudo-random number generators (CSPRNGs).

CSPRNGs: at the heart of secure encryption

Based on the random data supplied by the lava lamps, these generators produce the necessary encryption keys. Unlike ordinary PRNGs, CSPRNGs have to pass rigorous randomness tests. They must resist prediction attempts, even if part of the process is exposed

The random seed: an essential starting point

Each sequence of numbers derived from the lava lamp images constitutes a unique random seed. These seeds are regularly refreshed to maintain a high level of security and unpredictability.

Diversification of entropy sources

Although lava lamps are a major source of entropy for Cloudflare, the company also uses other methods to generate random data, including the interactions of operating systems such as Linux.

System resilience

Even in the event of camera obstruction or other unforeseen events, Cloudflare’s system remains robust. It relies on its multiple sources of entropy and the ability of its teams to resolve problems quickly.

An idea that already exists

This creative use of lava lamps for cryptography is not new. In the 1990s, Silicon Graphics developed a similar system. The Lavarand demonstrated continuous innovation in the field of computer security.

Cloudflare’s approach combines cutting-edge technology with creativity. It just goes to show that the most effective solutions can sometimes come from the most unexpected ideas.


Source : cloudflare.com/fr-fr/learning/ssl/lava-lamp-encryption/