[Cryptography] Lava Lamps Can Actually Create Secure File Encryptions - Here's How

[Steven M. Bellovin]

On 4 Mar 2026, at 14:31, Dan McDonald wrote:

>
> On Tue, Mar 03, 2026 at 02:36:11PM -0600, Aram Perez via cryptography wrote:
>>
>> As far as data encryption goes, you wouldn't expect a bunch of lights to
>> help secure anything — certainly not some '70s-style lava lamps. But as it
>> turns out, the exact opposite is true. Cloudflare, the major infrastructure
>> company that props up large portions of the internet, actually uses 100
>> lava lamps for SSL encryption. The blueprint, integral to secure
>> encryption, is randomness. The encryption "key" is what unlocks the data
>> for secure systems and allows it to be read. By keeping keys random, you
>> can essentially keep would-be hackers guessing, preventing unauthorized
>> parties from accessing the systems or data the encryption protects. This is
>> a lot like how encrypted messaging apps work, minus the psychedelic decor.
>
> 30 years and 2 months ago I interviewed at SGI and got to see the original
> "LavaRand" farm.
>

Yup: old concept. Here's the patent, filed in 1996: https://patents.google.com/patent/US5732138A/en?oq=US5732138A

        —Steve Bellovin, https://www.cs.columbia.edu/~smb