Apparently the motivation was to create a deterministic message key from the channel signing key.
I believe the message key is used to encrypt or sign messages.
Alternatives are:
pass in the hash of the private key
pass in the corresponding public key
...
These retain the desired property of a deterministic message key.
This doesn't align with best practices around handling private keys:
https://github.com/statechannels/go-nitro/blob/92d6f4d92c4e567181216a0517b631e7f6f65e05/client/engine/messageservice/p2p-message-service/service.go#L76
See https://www.notion.so/statechannels/RFC-8-Securing-Private-StateChannel-Key-c4f2945172d84db2b84220d64502e38c for details.
Apparently the motivation was to create a deterministic message key from the channel signing key. I believe the message key is used to encrypt or sign messages.
Alternatives are:
These retain the desired property of a deterministic message key.