I just posted an experimental repo exploring how we could use a persons face, voice print as well as a spoken secret phrase to deterministically generate a private key.
In this there, is a “notebook” of sample code which takes 2 pictures of a face, voice samples, and generates the same key twice from different source material with the phrase “my voice is my passport” (in reality - you want that phrase to be secret!).
You can explore the notebook here: experimental-face-voice-key/you_are_the_key.ipynb at main · TBD54566975/experimental-face-voice-key · GitHub
or play with it on google colab here: Google Colab if you are familiar with notebooks.
The aim here is that anything that we can do to make self-custody of private key material easier is good for SSI, and what could be easier than just being yourself in a way that it is near-impossible for anyone else to impersonate. This could be for key recovery if not for the key material itself.
Unfortunately, I am not an expert in any of these diverse domains, so any collaboration on voice prints, or facial biometrics and cryptography appreciated (this may not yield sufficiently secure results, but I am curios to see if is of interest to anyone).