Practical Cryptography for Developers

C# Crypto Libraries

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Last updated 4 years ago

// var privKey = EthECKey.GenerateKey(); // Random private key
var privKey = new EthECKey( "97ddae0f3a25b92268175400149d65d6887b9cefaf28ea2c078e05cdc15a3c0a");
byte[] pubKeyCompressed = new ECKey(
  privKey.GetPrivateKeyAsBytes(), true).GetPubKey(true);
Console.WriteLine("Private key: {0}",
  privKey.GetPrivateKey().Substring(4));
Console.WriteLine("Public key: {0}",
  privKey.GetPubKey().ToHex().Substring(2));
Console.WriteLine("Public key (compressed): {0}",
  pubKeyCompressed.ToHex());

string msg = "Message for signing";
byte[] msgBytes = Encoding.UTF8.GetBytes(msg);
byte[] msgHash = new Sha3Keccack().CalculateHash(msgBytes);
var signature = privKey.SignAndCalculateV(msgHash);

Console.WriteLine("Msg: {0}", msg);
Console.WriteLine("Msg hash: {0}", msgHash.ToHex());
Console.WriteLine("Signature: [v = {0}, r = {1}, s = {2}]",
  signature.V[0] - 27,
  signature.R.ToHex(),
  signature.S.ToHex());

var pubKeyRecovered =
  EthECKey.RecoverFromSignature(signature, msgHash);
Console.WriteLine("Recovered pubKey: {0}",
  pubKeyRecovered.GetPubKey().ToHex().Substring(2));

bool validSig = pubKeyRecovered.Verify(msgHash, signature);
Console.WriteLine("Signature valid? {0}", validSig);