@@ -2,15 +2,72 @@ package bip32
22
33import "github.com/btcsuite/btcd/btcec"
44
5+ // References:
6+ // [BIP32]: BIP0032 - Hierarchical Deterministic Wallets
7+ // https://github.com/bitcoin/bips/blob/master/bip-0032.mediawiki
8+
9+ // ExtendedKey specifies the basic api for a extended private or public key.
10+ // TODO: add the Zero method manually clears all fields and bytes in the
11+ // extended key. This can be used to explicitly clear key material from memory
12+ // for enhanced security against memory scraping. This function only clears
13+ // this particular key and not any children that have already been derived.
514type ExtendedKey interface {
15+ // AddressPubKeyHash returns the public key hash (20 bytes) derived from the
16+ // key, which would be itself for public keys and the extended public key
17+ // bound to it for private keys
618 AddressPubKeyHash () []byte
19+ // Child returns a derived child extended key at the given index. When this
20+ // extended key is a private extended key (as determined by the IsPrivate
21+ // function), a private extended key will be derived. Otherwise, the derived
22+ // extended key will be also be a public extended key.
23+ //
24+ // When the index is greater to or equal than the HardenedKeyStart constant,
25+ // the derived extended key will be a hardened extended key. It is only
26+ // possible to derive a hardended extended key from a private extended key.
27+ // Consequently, this function will return ErrDeriveHardFromPublic if a
28+ // hardened child extended key is requested from a public extended key.
29+ //
30+ // A hardened extended key is useful since, as previously mentioned, it
31+ // requires a parent private extended key to derive. In other words, normal
32+ // child extended public keys can be derived from a parent public extended
33+ // key (no knowledge of the parent private key) whereas hardened extended
34+ // keys may not be.
35+ //
36+ // NOTE: There is an extremely small chance (< 1 in 2^127) the specific child
37+ // index does not derive to a usable child. The ErrInvalidChild error should
38+ // be returned if this should occur, and the caller is expected to ignore the
39+ // invalid child and simply increment to the next index.
740 Child (i uint32 ) (ExtendedKey , error )
41+ // Depth returns the current derivation level with respect to the root.
42+ //
43+ // The root key has depth zero, and the field has a maximum of 255 due to
44+ // how depth is serialized.
845 Depth () uint8
46+ // Hardened tells if the key of interest is hardened, whose index is greater
47+ // than HardenedKeyStart.
948 Hardened () bool
49+ // Index returns the index of the key seen from its parent.
1050 Index () uint32
51+ // IsForNet checks if this key is in use for a given net specified by keyID
1152 IsForNet (keyID Magic ) bool
53+
54+ // Neuter returns a new extended public key from a extended private key. The
55+ // same extended key will be returned unaltered if it is already an extended
56+ // public key.
57+ //
58+ // As the name implies, an extended public key does not have access to the
59+ // private key, so it is not capable of signing transactions or deriving
60+ // child extended private keys. However, it is capable of deriving further
61+ // child extended public keys.
62+ Neuter () (* PublicKey , error )
63+ // ParentFingerprint returns a fingerprint of the parent extended key from
64+ // which this one was derived.
1265 ParentFingerprint () uint32
66+ // Public converts the extended key to a btcec public key and returns it.
1367 Public () (* btcec.PublicKey , error )
68+ // SetNet associates the extended key, and any child keys yet to be derived
69+ // from it, with the passed network.
1470 SetNet (keyID Magic )
71+ // String returns the extended key as a human-readable base58-encoded string.
1572 String () string
1673}
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