Document format

KeyHold v1 is a strict JSON object with six top-level fields:

Field	Meaning
format	Always keyhold for this format.
version	The supported document version, currently 1.
label	A human-readable, non-empty label.
publicKeyHex	A compressed secp256k1 public key in lowercase hex.
keyDerivation	PBKDF2-HMAC-SHA-256 parameters and salt.
cipher	AES-GCM parameters, IV, and ciphertext with tag.

The private key never appears as a JSON field. It is recovered only after password-based decryption and public-key matching.

Both SDKs reject extra fields and non-canonical base64url/hex values. Read the generated TypeScript API or Go API for exact signatures.