public ExtKey(CCKey key, byte[] chainCode, byte depth, byte[] fingerprint, uint child)
{
if (key == null)
{
throw new ArgumentNullException(nameof(key));
}
if (chainCode == null)
{
throw new ArgumentNullException(nameof(chainCode));
}
if (fingerprint == null)
{
throw new ArgumentNullException(nameof(fingerprint));
}
if (fingerprint.Length != 4)
{
throw new ArgumentException(string.Format("The fingerprint must be {0} bytes.", 4), "fingerprint");
}
if (chainCode.Length != ChainCodeLength)
{
throw new ArgumentException(string.Format("The chain code must be {0} bytes.", ChainCodeLength), "chainCode");
}
this.key = key;
this.nDepth = depth;
this.nChild = child;
parentFingerprint = new HDFingerprint(fingerprint);
Buffer.BlockCopy(chainCode, 0, vchChainCode, 0, ChainCodeLength);
}
public RootedKeyPath(HDFingerprint masterFingerprint, KeyPath keyPath)
{
if (keyPath == null)
{
throw new ArgumentNullException(nameof(keyPath));
}
_KeyPath = keyPath;
_MasterFingerprint = masterFingerprint;
}
public RootedKeyPath(IHDKey masterKey, KeyPath keyPath)
{
if (masterKey == null)
{
throw new ArgumentNullException(nameof(masterKey));
}
if (keyPath == null)
{
throw new ArgumentNullException(nameof(keyPath));
}
_KeyPath = keyPath;
_MasterFingerprint = new HDFingerprint(masterKey.GetPublicKey());
}
public static bool TryParse(string str, out HDFingerprint result)
{
if (str == null)
{
throw new ArgumentNullException(nameof(str));
}
result = default;
if (!HexEncoder.IsWellFormed(str) || str.Length != 4 * 2)
{
return(false);
}
result = new HDFingerprint(Encoders.Hex.DecodeData(str));
return(true);
}
/// <summary>
/// Constructor. Creates an extended key from the public key and corresponding private key.
/// </summary>
/// <remarks>
/// <para>
/// The ExtPubKey has the relevant values for child number, depth, chain code, and fingerprint.
/// </para>
/// </remarks>
public ExtKey(ExtPubKey extPubKey, CCKey privateKey)
{
if (extPubKey == null)
{
throw new ArgumentNullException(nameof(extPubKey));
}
if (privateKey == null)
{
throw new ArgumentNullException(nameof(privateKey));
}
this.nChild = extPubKey.nChild;
this.nDepth = extPubKey.nDepth;
this.vchChainCode = extPubKey.vchChainCode;
this.parentFingerprint = extPubKey.parentFingerprint;
this.key = privateKey;
}
public ExtPubKey(PubKey pubkey, byte[] chainCode, byte depth, HDFingerprint fingerprint, uint child)
{
if (pubkey == null)
{
throw new ArgumentNullException(nameof(pubkey));
}
if (chainCode == null)
{
throw new ArgumentNullException(nameof(chainCode));
}
if (chainCode.Length != ChainCodeLength)
{
throw new ArgumentException(string.Format("The chain code must be {0} bytes.", ChainCodeLength), "chainCode");
}
this.pubkey = pubkey;
this.nDepth = depth;
this.nChild = child;
parentFingerprint = fingerprint;
Buffer.BlockCopy(chainCode, 0, vchChainCode, 0, ChainCodeLength);
}
public static bool TryParse(string str, out RootedKeyPath result)
{
if (str == null)
{
throw new ArgumentNullException(nameof(str));
}
result = null;
var separator = str.IndexOf('/');
if (separator == -1)
{
return(false);
}
if (!HDFingerprint.TryParse(str.Substring(0, separator), out var fp))
{
return(false);
}
if (!KeyPath.TryParse(str.Substring(separator + 1), out var keyPath))
{
return(false);
}
result = new RootedKeyPath(fp, keyPath);
return(true);
}
/// <summary>
/// Recreates the private key of the parent from the private key of the child
/// combinated with the public key of the parent (hardened children cannot be
/// used to recreate the parent).
/// </summary>
public ExtKey GetParentExtKey(ExtPubKey parent)
{
if (parent == null)
{
throw new ArgumentNullException(nameof(parent));
}
if (Depth == 0)
{
throw new InvalidOperationException("This ExtKey is the root key of the HD tree");
}
if (IsHardened)
{
throw new InvalidOperationException("This private key is hardened, so you can't get its parent");
}
var expectedFingerPrint = new HDFingerprint(parent.PubKey);
if (parent.Depth != this.Depth - 1 || expectedFingerPrint != parentFingerprint)
{
throw new ArgumentException("The parent ExtPubKey is not the immediate parent of this ExtKey", "parent");
}
#if HAS_SPAN
Span <byte> pubkey = stackalloc byte[33];
Span <byte> l = stackalloc byte[64];
parent.PubKey.ToBytes(pubkey, out _);
Hashes.BIP32Hash(parent.vchChainCode, nChild, pubkey[0], pubkey.Slice(1), l);
var parse256LL = new Secp256k1.Scalar(l.Slice(0, 32), out int overflow);
if (overflow != 0 || parse256LL.IsZero)
{
throw new InvalidOperationException("Invalid extkey (this should never happen)");
}
if (!l.Slice(32, 32).SequenceEqual(vchChainCode))
{
throw new InvalidOperationException("The derived chain code of the parent is not equal to this child chain code");
}
var kPar = this.PrivateKey._ECKey.sec + parse256LL.Negate();
return(new ExtKey
{
vchChainCode = parent.vchChainCode,
nDepth = parent.Depth,
parentFingerprint = parent.ParentFingerprint,
nChild = parent.nChild,
key = new Key(new Secp256k1.ECPrivKey(kPar, this.PrivateKey._ECKey.ctx, true), true)
});
#else
byte[] l = null;
byte[] ll = new byte[32];
byte[] lr = new byte[32];
var pubKey = parent.PubKey.ToBytes();
l = Hashes.BIP32Hash(parent.vchChainCode, nChild, pubKey[0], pubKey.SafeSubarray(1));
Array.Copy(l, ll, 32);
Array.Copy(l, 32, lr, 0, 32);
var ccChild = lr;
BigInteger parse256LL = new BigInteger(1, ll);
BigInteger N = ECKey.CURVE.N;
if (!ccChild.SequenceEqual(vchChainCode))
{
throw new InvalidOperationException("The derived chain code of the parent is not equal to this child chain code");
}
var keyBytes = PrivateKey.ToBytes();
var key = new BigInteger(1, keyBytes);
BigInteger kPar = key.Add(parse256LL.Negate()).Mod(N);
var keyParentBytes = kPar.ToByteArrayUnsigned();
if (keyParentBytes.Length < 32)
{
keyParentBytes = new byte[32 - keyParentBytes.Length].Concat(keyParentBytes).ToArray();
}
var parentExtKey = new ExtKey
{
vchChainCode = parent.vchChainCode,
nDepth = parent.Depth,
parentFingerprint = parent.ParentFingerprint,
nChild = parent.nChild,
key = new CCKey(keyParentBytes)
};
return(parentExtKey);
#endif
}
public RootedKeyPath ToRootedKeyPath(HDFingerprint masterFingerprint)
{
return(new RootedKeyPath(masterFingerprint, this));
}