Client and backend. This class is shared: the same code is compiled into your app and into your server, so everything on this page works in both.

public final class Bip32

Object
Bip32

A BIP-32 hierarchical deterministic key on secp256k1: Bitcoin, every EVM chain and most others derive their accounts this way from one Mnemonic seed.

A node holds a private key, or only the public key once neuter has dropped it; a public node still derives every non-hardened child, which is how a watch-only server hands out deposit addresses without holding a secret. toXprv and toXpub write the standard serialization and parse reads it back.

Private key material lives in arrays this object owns; call destroy to wipe them.

Fields

`public static final long HARDENED = 2147483648L`	The offset that marks a hardened index.
`public static final int XPRV = 76066276`	The mainnet private version bytes, which print as `xprv`.
`public static final int XPUB = 76067358`	The mainnet public version bytes, which print as `xpub`.
`public static final int TPRV = 70615956`	The testnet private version bytes, which print as `tprv`.
`public static final int TPUB = 70617039`	The testnet public version bytes, which print as `tpub`.

Methods

`public static` `Bip32 master(byte[] seed)`	The master node of a seed (16 to 64 bytes, normally `Mnemonic.toSeed`).
`public static` `Bip32 parse(String extendedKey)`	Reads an extended key in its Base58Check form (`xprv...`, `xpub...`, `tprv...` or any other version bytes); `version` tells which.
`public int version()`	The version bytes this node was `parse`d with, or 0 for a derived node.
`public` `Bip32 child(long index)`	The child at `index`; add `HARDENED` for a hardened one, which needs the private key.
`public` `Bip32 derive(String path)`	Derives along a path relative to this node, such as `m/84'/0'/0'/0/7`.
`public` `Bip32 derive(DerivationPath path)`	Derives along a path relative to this node.
`public` `Bip32 neuter()`	This node without its private key.
`public boolean hasPrivateKey()`	Tells whether this node holds its private key.
`public byte[] privateKey()`	A copy of the 32-byte private key.
`public byte[] publicKey()`	A copy of the 33-byte compressed public key.
`public byte[] chainCode()`	A copy of the 32-byte chain code.
`public int depth()`	The distance from the master node.
`public long childNumber()`	The index this node was derived with, including `HARDENED`.
`public int parentFingerprint()`	The first four bytes of the parent’s key identifier, as a big-endian int; 0 for the master node.
`public int fingerprint()`	The first four bytes of `HASH160(publicKey)`, as a big-endian int.
`public` `String toXprv()`	The mainnet `xprv` serialization.
`public` `String toXpub()`	The mainnet `xpub` serialization.
`public` `String serialize(int versionBytes, boolean includePrivate)`	The serialization under any version bytes (SLIP-132 `zpub`, testnet `tpub`, …).
`public void destroy()`	Wipes the private key and chain code.

Inherited methods

From Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait, clone, finalize

Field details

HARDENED

public static final long HARDENED = 2147483648L

The offset that marks a hardened index.

XPRV

public static final int XPRV = 76066276

The mainnet private version bytes, which print as xprv.

XPUB

public static final int XPUB = 76067358

The mainnet public version bytes, which print as xpub.

TPRV

public static final int TPRV = 70615956

The testnet private version bytes, which print as tprv.

TPUB

public static final int TPUB = 70617039

The testnet public version bytes, which print as tpub.

Method details

master

public static Bip32 master(byte[] seed)

The master node of a seed (16 to 64 bytes, normally Mnemonic.toSeed).

Throws

IllegalArgumentException: for a seed out of range, or one whose master key is invalid (probability below 2^-127)

parse

public static Bip32 parse(String extendedKey)

Reads an extended key in its Base58Check form (xprv..., xpub..., tprv... or any other version bytes); version tells which.

Throws

IllegalArgumentException: for a malformed string, a bad checksum or a key that is not valid on the curve

version

public int version()

The version bytes this node was parsed with, or 0 for a derived node.

child

public Bip32 child(long index)

The child at index; add HARDENED for a hardened one, which needs the private key. When an index yields an invalid key, as BIP-32 allows with probability below 2^-127, the next index is used.

derive

public Bip32 derive(String path)

Derives along a path relative to this node, such as m/84'/0'/0'/0/7.

derive

public Bip32 derive(DerivationPath path)

Derives along a path relative to this node.

neuter

public Bip32 neuter()

This node without its private key.

hasPrivateKey

public boolean hasPrivateKey()

Tells whether this node holds its private key.

privateKey

public byte[] privateKey()

A copy of the 32-byte private key. Wipe it after use.

Throws

IllegalStateException: on a public-only node

publicKey

public byte[] publicKey()

A copy of the 33-byte compressed public key.

chainCode

public byte[] chainCode()

A copy of the 32-byte chain code.

depth

public int depth()

The distance from the master node.

childNumber

public long childNumber()

The index this node was derived with, including HARDENED.

parentFingerprint

public int parentFingerprint()

The first four bytes of the parent’s key identifier, as a big-endian int; 0 for the master node.

fingerprint

public int fingerprint()

The first four bytes of HASH160(publicKey), as a big-endian int.

toXprv

public String toXprv()

The mainnet xprv serialization.

toXpub

public String toXpub()

The mainnet xpub serialization.

serialize

public String serialize(int versionBytes, boolean includePrivate)

The serialization under any version bytes (SLIP-132 zpub, testnet tpub, …).

Parameters

versionBytes int: the four version bytes as a big-endian int
includePrivate boolean: true for the private form, which needs the private key

destroy

public void destroy()

Wipes the private key and chain code. The node is unusable afterwards.