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Cross platform C# wrapper for the native secp256k1 lib (netstandard2.0)

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Secp256k1.Net

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Cross platform C# wrapper for the native bitcoin-core/secp256k1 C library.

dotnet add package Secp256k1.Net

Platform Support

Pre-compiled binaries are bundled for the following platforms:

OS x64 x86 arm64
Windows ✓ ✓ ✓
Linux (glibc) ✓ ✓ ✓
Linux (musl/Alpine) ✓ ✓
macOS ✓ ✓

This library targets netstandard2.0 and net8.0, supporting a wide-range of .NET deployments: .NET Core 2.0+, .NET Framework 4.6.1+, Mono 5.4+, etc. Conditional compilation is used to enable optimized native library interop features available on modern targets (net8.0 and above).

Quick Start

using Secp256k1Net;
using System.Security.Cryptography;
using System.Text;

// Generate a key pair
var (secretKey, publicKey) = Secp256k1.CreateKeyPair(compressed: true);

// Sign a message (ECDSA)
byte[] message = SHA256.HashData(Encoding.UTF8.GetBytes("Hello, secp256k1!"));
byte[] signature = Secp256k1.Sign(message, secretKey);
bool isValid = Secp256k1.Verify(signature, message, publicKey);

// Schnorr signatures (BIP-340)
var (xOnlyPubKey, _) = Secp256k1.CreateXOnlyPublicKey(secretKey);
byte[] schnorrSig = Secp256k1.SignSchnorr(message, secretKey);
bool schnorrValid = Secp256k1.VerifySchnorr(schnorrSig, message, xOnlyPubKey);

// ECDH shared secret
var (aliceSecret, alicePublic) = Secp256k1.CreateKeyPair(compressed: true);
var (bobSecret, bobPublic) = Secp256k1.CreateKeyPair(compressed: true);
byte[] sharedSecret1 = Secp256k1.ComputeSharedSecret(bobPublic, aliceSecret);
byte[] sharedSecret2 = Secp256k1.ComputeSharedSecret(alicePublic, bobSecret);
// sharedSecret1 == sharedSecret2

See the examples project for more complete working examples.

API Reference

Full API Documentation

The Secp256k1 class exposes static functions that are idiomatic C#, using a thread-safe internal context:

Key Generation & Validation

  • CreateSecretKey() - Generate a cryptographically secure random secret key (example)
  • CreatePublicKey(secretKey, compressed) - Derive a serialized public key from a secret key (example)
  • CreateXOnlyPublicKey(secretKey) - Derive an x-only public key and parity for BIP-340 (example)
  • CreateKeyPair(compressed) - Generate a new secret key and public key pair (example)
  • IsValidSecretKey(secretKey) - Validate a secret key (example)
  • IsValidPublicKey(publicKey) - Validate a serialized public key (example)

Public Key Operations

  • CompressPublicKey(publicKey) - Convert a public key to 33-byte compressed format (example)
  • DecompressPublicKey(publicKey) - Convert a public key to 65-byte uncompressed format (example)
  • NegatePublicKey(publicKey, compressed) - Negate a public key (example)
  • CombinePublicKeys(publicKeys, compressed) - Add multiple public keys together (example)

ECDSA Signing & Verification

  • Sign(messageHash, secretKey) - Create a 64-byte compact ECDSA signature (example)
  • Verify(signature, messageHash, publicKey) - Verify an ECDSA signature (example)
  • SignRecoverable(messageHash, secretKey) - Create a recoverable signature with recovery ID (example)
  • RecoverPublicKey(signature, recoveryId, messageHash, compressed) - Recover public key from signature (example)

DER Signature Format

  • SignatureToDer(compactSignature) - Convert compact signature to DER format (example)
  • SignatureFromDer(derSignature) - Convert DER signature to compact format (example)
  • VerifyDer(derSignature, messageHash, publicKey) - Verify a DER-encoded signature (example)

Signature Normalization

  • NormalizeSignature(signature) - Normalize signature to lower-S form (example)
  • IsNormalizedSignature(signature) - Check if signature is in lower-S form (example)

Schnorr Signatures (BIP-340)

  • SignSchnorr(messageHash, secretKey, auxRand) - Create a Schnorr signature (example)
  • VerifySchnorr(signature, message, publicKey) - Verify a Schnorr signature (example)

ECDH Key Agreement

  • ComputeSharedSecret(publicKey, secretKey) - Compute ECDH shared secret (example)

Key Tweaking (BIP-32 HD Wallets)

  • TweakSecretKeyAdd(secretKey, tweak) - Add a tweak to a secret key (example)
  • TweakPublicKeyAdd(publicKey, tweak, compressed) - Add a tweak to a public key (example)
  • TweakSecretKeyMul(secretKey, tweak) - Multiply a secret key by a tweak (example)
  • TweakPublicKeyMul(publicKey, tweak, compressed) - Multiply a public key by a tweak (example)
  • NegateSecretKey(secretKey) - Negate a secret key (example)

Hashing

  • TaggedHash(tag, message) - Compute a BIP-340 tagged hash (example)

Advanced Usage

The Secp256k1 class also provides instance methods that are direct wrappers for the native C library, with near one-to-one API mapping. These offer more control over memory allocation and access to additional features:

Benchmarks

Secp256k1.Net is consistently 5-10x faster than the next best library (NBitcoin) and 20-100x faster than pure managed implementations like BouncyCastle, Nethereum, and StarkBank.


BenchmarkDotNet v0.15.8, macOS Sequoia 15.7.1 (24G231) [Darwin 24.6.0]
Apple M3 Max, 1 CPU, 14 logical and 14 physical cores
.NET SDK 10.0.102
  [Host]     : .NET 10.0.2 (10.0.2, 10.0.225.61305), Arm64 RyuJIT armv8.0-a
  DefaultJob : .NET 10.0.2 (10.0.2, 10.0.225.61305), Arm64 RyuJIT armv8.0-a
Method Categories Mean Error StdDev Ratio RatioSD
Secp256k1Net Ecdh 22.964 μs 0.1813 μs 0.1607 μs 1.00 0.01
NBitcoin Ecdh 167.133 μs 0.6087 μs 0.5694 μs 7.28 0.05
Nethereum Ecdh 500.696 μs 3.4009 μs 3.1812 μs 21.80 0.20
BouncyCastle Ecdh 503.882 μs 6.4419 μs 6.0257 μs 21.94 0.29
Secp256k1Net EcdsaRecover 36.042 μs 0.1504 μs 0.1333 μs 1.00 0.01
NBitcoin EcdsaRecover 268.565 μs 1.1492 μs 1.0187 μs 7.45 0.04
Nethereum EcdsaRecover 1,977.580 μs 14.0846 μs 12.4856 μs 54.87 0.39
BouncyCastle EcdsaRecover 2,270.418 μs 27.8990 μs 26.0967 μs 62.99 0.74
Secp256k1Net EcdsaSign 15.231 μs 0.0491 μs 0.0436 μs 1.00 0.00
NBitcoin EcdsaSign 133.297 μs 0.5326 μs 0.4721 μs 8.75 0.04
Nethereum EcdsaSign 319.805 μs 2.8822 μs 2.6960 μs 21.00 0.18
BouncyCastle EcdsaSign 312.781 μs 2.3212 μs 1.9383 μs 20.54 0.14
StarkBank EcdsaSign 1,085.330 μs 6.0425 μs 5.6522 μs 71.26 0.41
Chainers EcdsaSign 293.091 μs 4.1747 μs 3.9051 μs 19.24 0.25
Secp256k1Net EcdsaSignRecoverable 15.052 μs 0.0400 μs 0.0312 μs 1.00 0.00
NBitcoin EcdsaSignRecoverable 133.714 μs 0.7474 μs 0.6626 μs 8.88 0.05
Nethereum EcdsaSignRecoverable 1,376.987 μs 12.3970 μs 10.9896 μs 91.48 0.73
BouncyCastle EcdsaSignRecoverable 1,630.056 μs 17.9736 μs 16.8126 μs 108.29 1.10
Secp256k1Net EcdsaVerify 20.045 μs 0.1364 μs 0.1276 μs 1.00 0.01
NBitcoin EcdsaVerify 128.001 μs 1.1558 μs 1.0246 μs 6.39 0.06
Nethereum EcdsaVerify 588.907 μs 10.3029 μs 9.1332 μs 29.38 0.48
BouncyCastle EcdsaVerify 582.463 μs 8.7357 μs 8.1713 μs 29.06 0.43
StarkBank EcdsaVerify 2,105.913 μs 31.3613 μs 29.3354 μs 105.06 1.56
Secp256k1Net PubKeyCreate 9.759 μs 0.0638 μs 0.0566 μs 1.00 0.01
NBitcoin PubKeyCreate 95.283 μs 0.5591 μs 0.4956 μs 9.76 0.07
Nethereum PubKeyCreate 378.257 μs 2.0409 μs 1.9091 μs 38.76 0.29
BouncyCastle PubKeyCreate 377.224 μs 3.0774 μs 2.5698 μs 38.65 0.33
StarkBank PubKeyCreate 990.958 μs 9.6931 μs 9.0669 μs 101.54 1.06
Chainers PubKeyCreate 57.937 μs 0.5150 μs 0.4818 μs 5.94 0.06
Secp256k1Net SchnorrSign 20.296 μs 0.1379 μs 0.1290 μs 1.00 0.01
NBitcoin SchnorrSign 194.996 μs 1.0752 μs 0.9531 μs 9.61 0.07
Secp256k1Net SchnorrVerify 20.199 μs 0.1088 μs 0.1018 μs 1.00 0.01
NBitcoin SchnorrVerify 192.977 μs 0.4276 μs 0.3999 μs 9.55 0.05 

BenchmarkDotNet v0.15.8, Windows 11 (10.0.26100.7462/24H2/2024Update/HudsonValley) (Hyper-V)
Intel Xeon Platinum 8370C CPU 2.80GHz (Max: 2.79GHz), 1 CPU, 4 logical and 2 physical cores
.NET SDK 10.0.102
  [Host]   : .NET 10.0.2 (10.0.2, 10.0.225.61305), X64 RyuJIT x86-64-v4
  ShortRun : .NET 10.0.2 (10.0.2, 10.0.225.61305), X64 RyuJIT x86-64-v4

Job=ShortRun  IterationCount=3  LaunchCount=1  
WarmupCount=3
Method Categories Mean Error StdDev Ratio RatioSD
Secp256k1Net Ecdh 52.42 μs 9.141 μs 0.501 μs 1.00 0.01
NBitcoin Ecdh 298.68 μs 4.568 μs 0.250 μs 5.70 0.05
Nethereum Ecdh 928.84 μs 78.708 μs 4.314 μs 17.72 0.16
BouncyCastle Ecdh 1,028.87 μs 408.540 μs 22.393 μs 19.63 0.40
Secp256k1Net EcdsaRecover 83.14 μs 52.429 μs 2.874 μs 1.00 0.04
NBitcoin EcdsaRecover 521.88 μs 182.631 μs 10.011 μs 6.28 0.21
Nethereum EcdsaRecover 4,204.95 μs 1,926.313 μs 105.588 μs 50.61 1.87
BouncyCastle EcdsaRecover 4,681.68 μs 3,295.534 μs 180.639 μs 56.35 2.52
Secp256k1Net EcdsaSign 34.74 μs 17.371 μs 0.952 μs 1.00 0.03
NBitcoin EcdsaSign 235.00 μs 9.356 μs 0.513 μs 6.77 0.16
Nethereum EcdsaSign 615.69 μs 77.304 μs 4.237 μs 17.73 0.43
BouncyCastle EcdsaSign 603.43 μs 51.399 μs 2.817 μs 17.38 0.42
StarkBank EcdsaSign 1,610.20 μs 322.548 μs 17.680 μs 46.37 1.18
Chainers EcdsaSign 645.17 μs 356.116 μs 19.520 μs 18.58 0.66
Secp256k1Net EcdsaSignRecoverable 33.44 μs 0.760 μs 0.042 μs 1.00 0.00
NBitcoin EcdsaSignRecoverable 239.78 μs 161.529 μs 8.854 μs 7.17 0.23
Nethereum EcdsaSignRecoverable 2,486.05 μs 349.196 μs 19.141 μs 74.35 0.50
BouncyCastle EcdsaSignRecoverable 3,058.70 μs 1,589.421 μs 87.122 μs 91.47 2.26
Secp256k1Net EcdsaVerify 44.77 μs 4.161 μs 0.228 μs 1.00 0.01
NBitcoin EcdsaVerify 244.93 μs 11.689 μs 0.641 μs 5.47 0.03
Nethereum EcdsaVerify 1,108.03 μs 93.805 μs 5.142 μs 24.75 0.15
BouncyCastle EcdsaVerify 1,142.20 μs 138.179 μs 7.574 μs 25.51 0.18
StarkBank EcdsaVerify 3,164.81 μs 456.649 μs 25.030 μs 70.69 0.58
Secp256k1Net PubKeyCreate 23.61 μs 5.538 μs 0.304 μs 1.00 0.02
NBitcoin PubKeyCreate 180.93 μs 3.066 μs 0.168 μs 7.66 0.08
Nethereum PubKeyCreate 721.42 μs 41.428 μs 2.271 μs 30.56 0.35
BouncyCastle PubKeyCreate 748.16 μs 42.694 μs 2.340 μs 31.69 0.36
StarkBank PubKeyCreate 1,579.52 μs 48.830 μs 2.677 μs 66.91 0.75
Chainers PubKeyCreate 117.26 μs 3.038 μs 0.167 μs 4.97 0.06
Secp256k1Net SchnorrSign 45.42 μs 1.347 μs 0.074 μs 1.00 0.00
NBitcoin SchnorrSign 373.44 μs 27.746 μs 1.521 μs 8.22 0.03
Secp256k1Net SchnorrVerify 38.90 μs 8.268 μs 0.453 μs 1.00 0.01
NBitcoin SchnorrVerify 384.05 μs 9.204 μs 0.505 μs 9.87 0.10 

BenchmarkDotNet v0.15.8, Linux Ubuntu 24.04.3 LTS (Noble Numbat)
Intel Xeon Platinum 8370C CPU 2.80GHz (Max: 3.39GHz), 1 CPU, 4 logical and 2 physical cores
.NET SDK 10.0.102
  [Host]   : .NET 10.0.2 (10.0.2, 10.0.225.61305), X64 RyuJIT x86-64-v4
  ShortRun : .NET 10.0.2 (10.0.2, 10.0.225.61305), X64 RyuJIT x86-64-v4

Job=ShortRun  IterationCount=3  LaunchCount=1  
WarmupCount=3
Method Categories Mean Error StdDev Ratio RatioSD
Secp256k1Net Ecdh 53.32 μs 4.543 μs 0.249 μs 1.00 0.01
NBitcoin Ecdh 291.39 μs 36.415 μs 1.996 μs 5.47 0.04
Nethereum Ecdh 1,059.77 μs 348.103 μs 19.081 μs 19.88 0.32
BouncyCastle Ecdh 1,031.91 μs 129.167 μs 7.080 μs 19.35 0.14
Secp256k1Net EcdsaRecover 79.91 μs 1.059 μs 0.058 μs 1.00 0.00
NBitcoin EcdsaRecover 486.64 μs 6.764 μs 0.371 μs 6.09 0.01
Nethereum EcdsaRecover 4,022.64 μs 707.698 μs 38.791 μs 50.34 0.42
BouncyCastle EcdsaRecover 4,793.43 μs 863.738 μs 47.344 μs 59.99 0.51
Secp256k1Net EcdsaSign 38.09 μs 0.881 μs 0.048 μs 1.00 0.00
NBitcoin EcdsaSign 232.55 μs 8.640 μs 0.474 μs 6.11 0.01
Nethereum EcdsaSign 667.88 μs 26.910 μs 1.475 μs 17.53 0.04
BouncyCastle EcdsaSign 668.15 μs 86.774 μs 4.756 μs 17.54 0.11
StarkBank EcdsaSign 1,611.32 μs 50.303 μs 2.757 μs 42.30 0.08
Chainers EcdsaSign 660.49 μs 151.176 μs 8.286 μs 17.34 0.19
Secp256k1Net EcdsaSignRecoverable 37.37 μs 1.007 μs 0.055 μs 1.00 0.00
NBitcoin EcdsaSignRecoverable 232.93 μs 5.037 μs 0.276 μs 6.23 0.01
Nethereum EcdsaSignRecoverable 2,755.96 μs 242.894 μs 13.314 μs 73.75 0.32
BouncyCastle EcdsaSignRecoverable 3,459.83 μs 473.894 μs 25.976 μs 92.58 0.61
Secp256k1Net EcdsaVerify 44.42 μs 0.426 μs 0.023 μs 1.00 0.00
NBitcoin EcdsaVerify 236.92 μs 4.157 μs 0.228 μs 5.33 0.01
Nethereum EcdsaVerify 1,221.70 μs 529.962 μs 29.049 μs 27.51 0.57
BouncyCastle EcdsaVerify 1,210.26 μs 83.885 μs 4.598 μs 27.25 0.09
StarkBank EcdsaVerify 3,176.97 μs 376.794 μs 20.653 μs 71.53 0.40
Secp256k1Net PubKeyCreate 27.53 μs 0.828 μs 0.045 μs 1.00 0.00
NBitcoin PubKeyCreate 170.63 μs 1.680 μs 0.092 μs 6.20 0.01
Nethereum PubKeyCreate 795.21 μs 126.844 μs 6.953 μs 28.89 0.22
BouncyCastle PubKeyCreate 773.25 μs 234.863 μs 12.874 μs 28.09 0.41
StarkBank PubKeyCreate 1,536.89 μs 53.979 μs 2.959 μs 55.83 0.12
Chainers PubKeyCreate 118.50 μs 5.219 μs 0.286 μs 4.30 0.01
Secp256k1Net SchnorrSign 53.37 μs 1.060 μs 0.058 μs 1.00 0.00
NBitcoin SchnorrSign 354.83 μs 38.171 μs 2.092 μs 6.65 0.03
Secp256k1Net SchnorrVerify 37.96 μs 0.644 μs 0.035 μs 1.00 0.00
NBitcoin SchnorrVerify 369.41 μs 8.029 μs 0.440 μs 9.73 0.01

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Cross platform C# wrapper for the native secp256k1 lib (netstandard2.0)

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