keychain

var (
	// BIP32 hierarchical deterministic extended key magics
	// (i.e. for BTC, mainnet: 0x0488B21E public, 0x0488ADE4 private; testnet: 0x043587CF public, 0x04358394 private)
	HDPrivateKeyID = []byte{0x04, 0x20, 0xb9, 0x00} // starts with sprv
	HDPublicKeyID  = []byte{0x04, 0x20, 0xbd, 0x3a} // starts with spub

	// Prefix used when derive the hardened child private key.
	// I = HMAC-SHA512(Key = cpar, Data = 0x00 || ser256(kpar) || ser32(i)).
	// Note: The 0x00 pads the private key to make it 33 bytes long.
	PrefixDeriveHardenedPrivateKey = []byte{0x00}

	// masterKey is the master key used along with a random seed used to
	// generate the master node in the hierarchical tree.
	MasterKey = []byte("XuperCrypto seed")
)

var (
	// The caller should simply ignore the invalid index for generateing a child extended key at this time.
	// Just move to the next index. (increase the old index by 1)
	ErrInvalidIndexForGenerateChildKey = errors.New("this index is invalid for generating a child key.")

	// The error happens when the provided seed is not usable due to
	// the derived key falling outside of the valid range for the private keys.
	// This error indicates the caller must choose another seed.
	ErrUnusableSeed = errors.New("unusable seed")

	// Seed length must between 128 and 512 bits. Which means between 16 and 64 bytes.
	ErrInvalidSeedLength = errors.New("invalid seed length, must between 128 and 512 bits")

	// 密码学算法暂未被支持
	// Cryptography required for generating Mnemonic has not been supported yet.
	ErrCryptographyNotSupported = fmt.Errorf("this cryptography has not been supported yet.")

	// A hardened child extended key cannot be derived from a public extended key.
	ErrDeriveHardenKeyFromPublicKey = errors.New("cannot derive a hardened child extended key from a public extended key")

	// Cannot derive a key with more than 255 depth from a root key.
	ErrDeriveBeyondMaxDepth = errors.New("cannot derive a key with more than 255 depth in its path from a root key")

	// Cannot create a private ecdsa key from a public extended key.
	ErrNotPrivExtKey = errors.New("cannot to create a private ecdsa key from a public extended key")

	// The checksum contained in the 58-encoded string(a serialized extended key) is not right.
	ErrWrongChecksum = errors.New("wrong extended key checksum")

	// The pubKeyStr contained in the extended key is not right.
	ErrWrongPubKeyStr = errors.New("wrong PubKeyStr")

	// Wrong param for deriving corresponding private child key from child public key.
	ErrWrongParamForDerivingPrivateChildKey = errors.New("wrong param when trying to derive child private key from child public key.")
)