public string CalculateProofOfWork()
{
string difficulty = DifficultyString();
var stopWatch = new Stopwatch();
stopWatch.Start();
while (true)
{
var hashedData = Convert.ToBase64String(Hashing.ComputeHashSha256(Encoding.UTF8.GetBytes(Nonce + MyData)));
if (hashedData.StartsWith(difficulty, StringComparison.Ordinal))
{
stopWatch.Stop();
TimeSpan ts = stopWatch.Elapsed;
var elapsedTime = String.Format("{0:00}:{1:00}:{2:00}.{3:00}", ts.Hours, ts.Minutes, ts.Seconds, ts.Milliseconds / 10);
Console.WriteLine($"Difficulty level {Difficulty} - Nonce = {Nonce} - Elapsed time: {elapsedTime} - {hashedData}");
return(hashedData);
}
Nonce++;
}
}
public string CalculateBlockHash(string previousBlockHash)
{
var blockHeader = BlockNumber + CreatedDate.ToString() + previousBlockHash;
var combined = merkleTree.RootNode + blockHeader;
return(Convert.ToBase64String(Hashing.ComputeHashSha256(Encoding.UTF8.GetBytes(combined))));
}
public bool IsValidChain(string prevBlockHash, bool verbose)
{
bool isValid = true;
bool validSignature = false;
BuildMerkleTree();
validSignature = KeyStore.VerifyBlock(BlockHash, BlockSignature);
string newBlockHash = Convert.ToBase64String(Hashing.ComputeHashSha256(Encoding.UTF8.GetBytes(Nonce + CalculateBlockHash(prevBlockHash))));
validSignature = KeyStore.VerifyBlock(newBlockHash, BlockSignature);
if (newBlockHash != BlockHash)
{
isValid = false;
}
else
{
isValid |= PreviousBlockHash == prevBlockHash;
}
PrintVerificationMessage(verbose, isValid, validSignature);
if (NextBlock != null)
{
return(NextBlock.IsValidChain(newBlockHash, verbose));
}
return(isValid);
}
public string CalculateProofOfWork(string blockHash)
{
string difficulty = DifficultyString();
Stopwatch stopWatch = new Stopwatch();
stopWatch.Start();
while (true)
{
string hashedData = Convert.ToBase64String(Hashing.ComputeHashSha256(Encoding.UTF8.GetBytes(Nonce + blockHash)));
if (hashedData.StartsWith(difficulty, StringComparison.Ordinal))
{
stopWatch.Stop();
TimeSpan ts = stopWatch.Elapsed;
// Format and display the TimeSpan value.
string elapsedTime = String.Format("{0:00}:{1:00}:{2:00}.{3:00}", ts.Hours, ts.Minutes, ts.Seconds, ts.Milliseconds / 10);
Console.WriteLine("Difficulty Level " + Difficulty + " - Nonce = " + Nonce + " - Elapsed = " + elapsedTime + " - " + hashedData);
return(hashedData);
}
Nonce++;
}
}
public void send_a_message_with_digital_signature_expect_intercepted_message_as_invalid()
{
// User generates a message, hashes the message and signs it with their PRIVATE key //
var message = Encoding.UTF8.GetBytes("This is a message that will be changed after the digital signature.");
// User sends the message //
byte[] hashedMessage = Hashing.ComputeHashSha256(message);
// Receiver calculates the hash of the encrypted data //
var digitalSignature = new DigitalSignature();
digitalSignature.AssignNewKey();
// this signature is sent along with the message ? //
var signature = digitalSignature.SignData(hashedMessage);
// Message intercepted and altered //
message = Encoding.UTF8.GetBytes("This is a message that was intercepted after the signature.");
hashedMessage = Hashing.ComputeHashSha256(message);
// Receiver verifies the digital signature using the public key //
var verified = digitalSignature.VerifySignature(hashedMessage, signature);
// the message should be verified at this point//
Assert.IsFalse(verified);
}
public string CalculateBlockHash(string previousBlockHash)
{
var properties = this.dataItem.ToString();
string blockHeader = BlockNumber + CreatedOn.ToString() + previousBlockHash;
string combined = properties + blockHeader;
return(Convert.ToBase64String(Hashing.ComputeHashSha256(Encoding.UTF8.GetBytes(combined))));
}
public string CalculateBlockHash(string previousBlockHash)
{
var tnxHash = ClaimNumber + SettlementAmount + SettlementDate + CarRegistration + Mileage + ClaimType;
var blockHeader = BlockNumber + CreatedDate.ToString() + previousBlockHash;
var combined = tnxHash + blockHeader;
return(Convert.ToBase64String(Hashing.ComputeHashSha256(Encoding.UTF8.GetBytes(combined))));
}
public void Hash_Test_Pass()
{
var document = Encoding.UTF8.GetBytes("Document to Sign");
byte[] hashedDocument = Hashing.ComputeHashSha256(document);
string actual = Encoding.UTF8.GetString(hashedDocument);
Assert.AreNotEqual(document, actual);
}
public string CalculateBlockHash(string previousBlockHash)
{
var blockHeader = BlockNumber + CreatedDate.ToString() + previousBlockHash;
var combined = merkleTree.RootNode + blockHeader;
string completeBlockHash;
if (KeyStore == null)
{
completeBlockHash = Convert.ToBase64String(Hashing.ComputeHashSha256(Encoding.UTF8.GetBytes(combined)));
}
else
{
completeBlockHash = Convert.ToBase64String(HMAC.ComputeHmacSha256(Encoding.UTF8.GetBytes(combined), KeyStore.AuthenticatedHashKey));
}
return(completeBlockHash);
}
public void send_a_message_with_digital_signature_expect_message_validation()
{
// User generates a message, hashes the message and signs it with their PRIVATE key //
var message = Encoding.UTF8.GetBytes("This is a message that will be verified through digital signature.");
// User sends the message //
byte[] hashedMessage = Hashing.ComputeHashSha256(message);
// Receiver calculates the hash of the encrypted data //
var digitalSignature = new DigitalSignature();
digitalSignature.AssignNewKey();
// Receiver verifies the digital signature using the public key //
var signature = digitalSignature.SignData(hashedMessage);
var verified = digitalSignature.VerifySignature(hashedMessage, signature);
// the message should be verified at this point//
Assert.IsTrue(verified);
}
public string CalculateTransactionHash()
{
string txnHash = ClaimNumber + SettlementAmount + SettlementDate + CarRegistration + Mileage + ClaimType;
return(Convert.ToBase64String(Hashing.ComputeHashSha256(Encoding.UTF8.GetBytes(txnHash))));
}
