NBip32Fast

High perfomance and low allocation BIP-32 HD key derivation library for .NET 9+

Usage

Basic

var der = new Bip32Key();

Secp256K1HdKey.Instance.DerivePath("m/44'/0'/0'/0/0", seed, ref der);
NistP256HdKey.Instance.DerivePath("m/44'/0'/0'/0/0", seed, ref der);
Ed25519HdKey.Instance.DerivePath("m/44'/0'/0'/0'/0'", seed, ref der);

Extended (tree-like)

var master = new Bip32Key();
Ed25519HdKey.Instance.DerivePath("m/44'/888'/0'/0'", seed, ref master);

var accounts = new List<byte[]>();

var derResult = new Bip32Key();
for (var i = 0u; i < 5u; i++)
{
    Ed25519HdKey.Instance.Derive(ref master, KeyPathElement.Hard(i), ref derResult);
    accounts.Add(Ed25519HdKey.Instance.GetPublic(derResult.Key));
}

Sibling scan (many children of one parent)

When deriving many soft children of the same parent (e.g. scanning wallet addresses m/44'/60'/0'/0/{i}), wrap the parent in a Bip32Parent. It computes the parent public key once and reuses it for every child, instead of one EC multiplication per child — about 10x faster for secp256k1:

var account = new Bip32Key();
Secp256K1HdKey.Instance.DerivePath("m/44'/60'/0'/0", seed, ref account);

var parent = new Bip32Parent(in account, Secp256K1HdKey.Instance);

var child = new Bip32Key();
for (var i = 0u; i < 1000u; i++)
{
    parent.Derive(KeyPathElement.Soft(i), ref child); // EC point multiplication happens once, not 1000 times
    // use child.Key / child.ChainCode
}

Hardened indices work too (they simply take the regular path, since no public key is involved).

Method	Count	Mean	Ratio	Allocated
CachedParentDerive	100	142.6 us	0.10	-
PlainDerive	100	1,424.7 us	1.00	-

Benchmarks

AMD Ryzen Threadripper 7980X 64-Cores 2.18GHz, 1 CPU, 128 logical and 64 physical cores (lower values is better)

SecP256K1

Method	Mean	Error	StdDev	Ratio	RatioSD	Allocated	Alloc Ratio
NBip32FastKey	36.08 us	0.042 us	0.037 us	1.00	0.00	104 B	1.00
NBitcoinKey	884.07 us	3.557 us	3.327 us	24.50	0.09	9296 B	89.38
NetezosKey	931.24 us	5.300 us	4.958 us	25.81	0.14	3281497 B	31,552.86

Ed25519

Method	Mean	Error	StdDev	Ratio	Allocated	Alloc Ratio
NBip32FastKey	7.186 us	0.0119 us	0.0106 us	1.00	104 B	1.00
NetezosKey	8.738 us	0.0243 us	0.0216 us	1.22	5448 B	52.38
P3HdKey	9.460 us	0.0338 us	0.0300 us	1.32	6112 B	58.77

NistP256

Method	Mean	Error	StdDev	Ratio	RatioSD	Allocated	Alloc Ratio
NBip32FastKey	167.2 us	0.53 us	0.49 us	1.00	0.00	608 B	1.00
NetezosKey	1,483.8 us	11.86 us	10.51 us	8.87	0.07	7029510 B	11,561.69

Parse + .ToString() KeyPath

Method	Mean	Error	StdDev	Ratio	RatioSD	Allocated	Alloc Ratio
NBip32FastParse	41.12 ns	0.071 ns	0.060 ns	1.00	0.00	56 B	1.00
NBitcoinParse	292.12 ns	1.571 ns	1.469 ns	7.10	0.04	1104 B	19.71
NetezosParse	317.28 ns	1.028 ns	0.962 ns	7.72	0.03	992 B	17.71

Benchmark code

TODOs

• Ed25519 soft derivation scheme (used in Cardano)
• KeyPathTree for efficient computing (for multiple keypath merging and index depth)
• HDKey refactoring with public key lazy addition
• More testing