offline
Exports a full ECDSA private key offline(xpriv according to BIP-32).
Combines secret shares locally to compute the full private key(xpriv). Useful in an offline recovery setting where key shares are collected manually and used to recover the full private key on an air-gapped device.
Return
The full private key(xpriv) as a string
Parameters
secret
A list of secret shares (at least threshold number)