Non-Programmatic Deterministic Key Generation for ED25519 and ED448 Keys

[Syfer Shock!]

I need a non-programmatic method for using seeds to generate ED25519
and ED448 (Goldilocks) key pairs. This means using only shell-accessible
tools within OpenSSL rather than binding programmatically.

While reading the documentation it seems that neither 'genpkey' nor
'pkeyutl' have a facility for using a deterministic seed to generate
the keys. Maybe I am missing something.

I notice that OpenSSL has the 'asn1parse' utility for reading PEM and
DER formatted keys. Is there an analogue that allows to write back a new
value for the secret integers in private keys? Or can I encode data
with 'asn1parse' and then output it in PEM format to build a key?

Trying to de-serialize and reconstruct keys outside of OpenSSL is a pain
and might hinder portability and require re-writing the same code to
different targets. I would rather try to find a way to use the native
shell commands so I may set it and forget it.

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