Cipherseks Double Plate can be found on github. Claims to be:

  • 2mm thick highly polished stainless steel
  • fireproof to 1,400°C / 2,550°F
  • waterproof
  • corrosion resistant


These plates already had some pre-etched markings though they weren’t as deep as a center punch would be. I center punched a few divots just to see how they would fare in comparison. Note that the written seed words are meant to be wiped off and are only supposed to be a temporary template. I’m not convinced that these temporary templates are worth the extra space they use on the device.

I’m a bit worried about the tiny screws because I often see tiny screws fail due to getting stripped or deformed.

Heat Stress Test

The device itself survived just fine, however my initial fears about the screws were proven justified. I was only able to unscrew half of the screws while the others got stripped. I’m sure the data inside is fine, but this is an annoying usability issue.

Corrosion Stress Test

In both a good and bad twist, the acid completely dissolved the screws that had seized up and prevented me from opening the device after the heat test. Now we can see that the straight punched divots are holding up well, though the other types of markings did not. What’s more concerning is that the template is completely gone. This would be very problematic if you were unable to find a replacement copy of this device’s template.

Crush Stress Test

No additional data loss after previous tests.