Find the private key that can sign for a given compressed public key.
Parameters
pubkey: string
Compressed SEC1 public key (33 bytes, hex-encoded) to match against.
privkeys: string|string[]
One or more candidate private keys (hex-encoded).
Returns string
The private key hex string that signs for pubkey.
Remarks
Matches on the x coordinate: a key imported from an x-only context (any nostr key) is published
as 02 || x but its scalar derives the odd-y twin half the time. That twin is n - d, and it is
what gets returned, so the caller signs for the point the quote actually names.
Throws
If no candidate key derives to the expected pubkey.
Find the private key that can sign for a given compressed public key.