private static void TestEncryptWithHmacHelper(int length, AxCryptOptions options)
{
byte[] output;
byte[] hmacKey;
using (MemoryStream inputStream = new MemoryStream())
{
byte[] text = Resolve.RandomGenerator.Generate(length);
inputStream.Write(text, 0, text.Length);
inputStream.Position = 0;
using (MemoryStream outputStream = new MemoryStream())
{
using (V2AxCryptDocument document = new V2AxCryptDocument(new EncryptionParameters(new V2Aes256CryptoFactory().CryptoId, new Passphrase("Secret")), 100))
{
document.EncryptTo(inputStream, outputStream, options);
output = outputStream.ToArray();
hmacKey = document.DocumentHeaders.GetHmacKey();
}
}
}
byte[] hmacBytesFromHeaders = new byte[V2Hmac.RequiredLength];
Array.Copy(output, output.Length - V2Hmac.RequiredLength, hmacBytesFromHeaders, 0, V2Hmac.RequiredLength);
V2Hmac hmacFromHeaders = new V2Hmac(hmacBytesFromHeaders);
byte[] dataToHmac = new byte[output.Length - (V2Hmac.RequiredLength + 5)];
Array.Copy(output, 0, dataToHmac, 0, dataToHmac.Length);
HMACSHA512 hmac = new HMACSHA512(hmacKey);
hmac.TransformFinalBlock(dataToHmac, 0, dataToHmac.Length);
V2Hmac hmacFromCalculation = new V2Hmac(hmac.Hash);
Assert.That(hmacFromHeaders, Is.EqualTo(hmacFromCalculation));
}
public void TestWriteWithHmac()
{
V2DocumentHeaders headers = new V2DocumentHeaders(new EncryptionParameters(new V2Aes256CryptoFactory().CryptoId, new Passphrase("v2passzz")), 20);
byte[] output;
V2HmacCalculator hmacCalculator = new V2HmacCalculator(new SymmetricKey(headers.GetHmacKey()));
using (V2HmacStream <MemoryStream> hmacStream = V2HmacStream.Create <MemoryStream>(hmacCalculator, new MemoryStream()))
{
headers.WriteStartWithHmac(hmacStream);
headers.WriteEndWithHmac(hmacCalculator, hmacStream, 0, 0);
hmacStream.Flush();
output = hmacStream.Chained.ToArray();
}
byte[] hmacBytesFromHeaders = new byte[V2Hmac.RequiredLength];
Array.Copy(output, output.Length - V2Hmac.RequiredLength, hmacBytesFromHeaders, 0, V2Hmac.RequiredLength);
V2Hmac hmacFromHeaders = new V2Hmac(hmacBytesFromHeaders);
byte[] dataToHmac = new byte[output.Length - (V2Hmac.RequiredLength + 5)];
Array.Copy(output, 0, dataToHmac, 0, dataToHmac.Length);
HMACSHA512 hmac = new HMACSHA512(headers.GetHmacKey());
hmac.TransformFinalBlock(dataToHmac, 0, dataToHmac.Length);
V2Hmac hmacFromCalculation = new V2Hmac(hmac.Hash);
Assert.That(hmacFromHeaders, Is.EqualTo(hmacFromCalculation));
}