static void Main(string[] args)
{
// Set colors to green on black, because everyone knows that's what hackers use
Console.ForegroundColor = ConsoleColor.Green;
Console.BackgroundColor = ConsoleColor.Black;
Console.Clear();
// Show banner
Console.WriteLine("Developer Secrets Sender - Generation 4 (symmetric encryption with asymmetric key exchange)");
Console.WriteLine("Copyright (c) Michal A. Valasek - Altairis, 2016");
Console.WriteLine(new string('-', Console.WindowWidth - 1));
Console.WriteLine();
// Get your partner's public key
Console.WriteLine("Enter your partner's public key:");
var partnerPublicKeyString = Console.ReadLine();
var partnerPublicKey = partnerPublicKeyString.FromBase16().ToPublicKeyFromBlob();
Console.WriteLine();
// Create ephemeral bundle
var ephemeralBundle = partnerPublicKey.GetSharedEphemeralDhmSecret();
// Send ephemeral public key to partner
var ephemeralPublicKeyString = ephemeralBundle.EphemeralDhmPublicKeyBlob.ToBase16();
Console.WriteLine("This is your ephemeral public key:");
Console.WriteLine(ephemeralPublicKeyString);
Console.WriteLine("Send it to your chat partner. The adversary can read the key, but should not be able modify it.");
Console.WriteLine();
// Get shared secret (master key)
var masterKey = ephemeralBundle.SharedSecret;
Console.WriteLine("This is your master key (displayed for demonstration only): ");
Console.WriteLine(masterKey.ToBase16());
Console.WriteLine();
// Get queue
var q = GetQueue(CONNECTION_STRING, QUEUE_NAME);
// Main loop
Console.WriteLine("Enter message to send or empty string to quit:");
uint messageNumber = 0;
while (true)
{
// Get message to send
Console.Write("> ");
var line = Console.ReadLine();
if (string.IsNullOrWhiteSpace(line))
{
break;
}
// Increment counter
messageNumber++;
// Derive key using NIST SP 800-108 algorithm in counter mode
var context = BitConverter.GetBytes(messageNumber);
var derivedKey = new byte[32].AsArraySegment();
SP800_108_Ctr.DeriveKey(HMACFactories.HMACSHA256, masterKey, null, context.AsArraySegment(), derivedKey, messageNumber);
// Encrypt message
var encryptedData = SuiteB.Encrypt(derivedKey.Array, line.ToBytes().AsArraySegment());
var encryptedString = string.Join("|", messageNumber, encryptedData.ToBase16());
// Prepare and send message
var msg = new CloudQueueMessage(encryptedString);
q.AddMessage(msg);
// Display results
Console.WriteLine($"< Message #{messageNumber} sent");
}
Console.WriteLine("Program terminated successfully");
}
static void Main(string[] args)
{
// Set colors to green on black, because everyone knows that's what hackers use
Console.ForegroundColor = ConsoleColor.Green;
Console.BackgroundColor = ConsoleColor.Black;
Console.Clear();
// Show banner
Console.WriteLine("Developer Secrets Receiver - Generation 3 (symmetric encryption with key derivation)");
Console.WriteLine("Copyright (c) Michal A. Valasek - Altairis, 2016");
Console.WriteLine(new string('-', Console.WindowWidth - 1));
Console.WriteLine();
// Create master symmetric key
var rnd = new CryptoRandom();
var masterKey = rnd.NextBytes(32);
var masterKeyString = masterKey.ToBase16();
Console.WriteLine("This is your master symmetric key: " + masterKeyString);
Console.WriteLine("Send it to your chat partner safely!");
Console.WriteLine();
// Get queue
var q = GetQueue(CONNECTION_STRING, QUEUE_NAME);
// Main loop
Console.WriteLine("Waiting for messages. Press SPACEBAR for pause, ESC for exit.");
Console.WriteLine();
uint expectedMessageNumber = 1;
while (true)
{
// Wait to receive message
var msg = q.GetMessage();
if (msg == null)
{
// No more messages
if (Console.KeyAvailable)
{
var keyCode = Console.ReadKey(intercept: true);
if (keyCode.Key == ConsoleKey.Escape)
{
break;
}
if (keyCode.Key == ConsoleKey.Spacebar)
{
Console.WriteLine();
Console.WriteLine("Paused, press any key to continue...");
Console.ReadKey(intercept: true);
Console.WriteLine("Waiting for messages. Press SPACEBAR for pause, ESC for exit.");
Console.WriteLine();
}
}
Thread.Sleep(250);
continue;
}
// Delete message from queue
q.DeleteMessage(msg);
// Parse message
var messageParts = msg.AsString.Split('|');
uint messageNumber = uint.Parse(messageParts[0]);
var cipherData = messageParts[1].FromBase16();
// Validate message number
if (messageNumber < expectedMessageNumber)
{
// Received number is too low - message is repeated or out of order
Console.WriteLine($"WARNING! The following message has too low serial number (expected {expectedMessageNumber}, got {messageNumber}.");
Console.WriteLine($" Message is repeated or was delivered out of order.");
}
else if (messageNumber > expectedMessageNumber)
{
// Received number is too high - some messages are missing or out of order
Console.WriteLine($"WARNING! The following message has too high serial number (expected {expectedMessageNumber}, got {messageNumber}.");
Console.WriteLine($" Message was delivered out of order or some messages are missing.");
expectedMessageNumber = messageNumber + 1;
}
else
{
// Received number is correct
expectedMessageNumber++;
}
// Derive key using HKDF algorithm
var context = BitConverter.GetBytes(messageNumber);
var derivedKey = new byte[32].AsArraySegment();
SP800_108_Ctr.DeriveKey(HMACFactories.HMACSHA256, masterKey, null, context.AsArraySegment(), derivedKey, messageNumber);
// Authenticate message
var authenticated = SuiteB.Authenticate(derivedKey.Array, cipherData.AsArraySegment());
if (!authenticated)
{
Console.WriteLine($"< Message #{messageNumber} ({msg.Id}) from {msg.InsertionTime:yyyy-MM-dd HH:mm:ss} was tampered with!");
continue;
}
// Decrypt message
var plainData = SuiteB.Decrypt(derivedKey.Array, cipherData.AsArraySegment());
var plainString = plainData.FromBytes();
// Display message
Console.WriteLine($"< Message #{messageNumber} ({msg.Id}) from {msg.InsertionTime:yyyy-MM-dd HH:mm:ss}:");
Console.WriteLine(plainString);
}
Console.WriteLine("Program terminated successfully.");
}
static void Main(string[] args)
{
// Set colors to green on black, because everyone knows that's what hackers use
Console.ForegroundColor = ConsoleColor.Green;
Console.BackgroundColor = ConsoleColor.Black;
Console.Clear();
// Show banner
Console.WriteLine("Developer Secrets Sender - Generation 3 (symmetric encryption with key derivation)");
Console.WriteLine("Copyright (c) Michal A. Valasek - Altairis, 2016");
Console.WriteLine(new string('-', Console.WindowWidth - 1));
Console.WriteLine();
// Get secret key
Console.Write("Enter your partner's master symmetric key: ");
var masterKeyString = Console.ReadLine();
var masterKey = masterKeyString.FromBase16();
Console.WriteLine();
// Get queue
var q = GetQueue(CONNECTION_STRING, QUEUE_NAME);
// Main loop
Console.WriteLine("Enter message to send or empty string to quit:");
uint messageNumber = 0;
while (true)
{
// Get message to send
Console.Write("> ");
var line = Console.ReadLine();
if (string.IsNullOrWhiteSpace(line))
{
break;
}
// Increment counter
messageNumber++;
// Derive key using NIST SP 800-108 algorithm in counter mode
var context = BitConverter.GetBytes(messageNumber);
var derivedKey = new byte[32].AsArraySegment();
SP800_108_Ctr.DeriveKey(
HMACFactories.HMACSHA256,
masterKey,
null,
context.AsArraySegment(),
derivedKey,
messageNumber);
// Encrypt message
var encryptedData = SuiteB.Encrypt(derivedKey.Array, line.ToBytes().AsArraySegment());
var encryptedString = string.Join("|", messageNumber, encryptedData.ToBase16());
// Prepare and send message
var msg = new CloudQueueMessage(encryptedString);
q.AddMessage(msg);
// Display results
Console.WriteLine($"< Message #{messageNumber} sent");
}
Console.WriteLine("Program terminated successfully");
}
