Exactly which key types does the Librem Key support?

I reached out to support about this in December and wanted to see if anyone who owns a Librem Key could give a more definitive answer. The Librem Key is based on the Nitrokey Pro v2, which according to page 3 of its datasheet has slots for “3 x RSA 2048-4096 bit or 3 x ECC 256-521 bit, 1 x AES-128 or AES-256” keys.

The Librem Key technical specs list the key slots as “Three key slots supporting RSA 2048-4096 bit and ECC 256-512 bit.”

I was told that Purism’s CSO thought the “ECC 521 bit” key was a typo in the Nitrokey datasheet and that the Librem Key “should” support AES 128 and 256 bit keys, but that they hadn’t had a chance to test it. I checked the specs page again today out of curiosity and saw that it hasn’t been updated to reflect whether or not AES keys are supported.


  1. Is there such a thing as an ECC 512 bit key, or should this be ECC 521 bit?
  2. Can anyone confirm whether or not the Librem Key supports AES 128 and 256 bit keys?
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I believe it’s not a typo i.e. intentionally 521.

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