Function deriveSecretAndBlindingFactor

deriveSecretAndBlindingFactor(
    seed: Uint8Array,
    keysetId: string,
    counter: number,
): { blindingFactor: Uint8Array; secret: Uint8Array }
Derives the deterministic secret and blinding factor for one counter.
Parameters
- seed: Uint8Array
  Wallet seed used for deterministic derivation.
- keysetId: string
  Mint keyset ID that selects the derivation method.
- counter: number
  Deterministic counter for the output.
Returns { blindingFactor: Uint8Array; secret: Uint8Array }
The derived secret bytes and blinding factor bytes.

Remarks
This is the preferred NUT-13 derivation API because deterministic output construction needs both values for the same seed, keyset, and counter. For deprecated BIP-32 keysets, deriving both values together is faster because it avoids repeating the shared path derivation common to the secret and blinding factor.

The function supports legacy base64 keyset IDs, deprecated hex keyset IDs with the 00 prefix, and modern hex keyset IDs with the 01 prefix.

Throws
CTSError If the keyset ID version is unsupported or if derivation produces an invalid private key.
- Defined in src/crypto/NUT13.ts:64