/// <summary>
/// Returns data hashed with provided algorithm.
/// </summary>
/// <param name="hashAlgorithm">The hash algorithm.</param>
/// <returns>Byte array containing hash of data.</returns>
/// <exception cref="TimestampException">
/// Invalid digest length for given algorithm
/// </exception>
public byte[] GetHashedData(HashAlgorithm hashAlgorithm)
{
System.Security.Cryptography.HashAlgorithm algorithm = System.Security.Cryptography.HashAlgorithm.Create(hashAlgorithm.ToString());
switch (mode)
{
case DataMode.DATA_1:
return(algorithm.ComputeHash(data));
case DataMode.STREAM_1:
return(algorithm.ComputeHash(stream));
case DataMode.PATH_1:
try
{
return(algorithm.ComputeHash(File.OpenRead(pathToFile)));
}
catch (Exception e)
{
throw new TimestampException("Can't calculate message digest from file: " + pathToFile, e);
}
case DataMode.HASHED_1:
if (digest.Length != hashAlgorithm.GetLength())
{
throw new TimestampException("Invalid digest length for given algorithm");
}
return(digest);
case DataMode.DATA_N:
for (int i = 0; i < datas.Length - 1; i++)
{
algorithm.TransformBlock(datas[i], 0, datas[i].Length, datas[i], 0);
}
algorithm.TransformFinalBlock(datas[datas.Length - 1], 0, datas[datas.Length - 1].Length);
return(algorithm.Hash);
case DataMode.STREAM_N:
using (MemoryStream finalStream = new MemoryStream())
{
foreach (Stream stream in streams)
{
stream.CopyTo(finalStream);
}
return(algorithm.ComputeHash(finalStream.ToArray()));
}
case DataMode.PATH_N:
int numberOfFiles = pathsToFiles.Length;
for (int i = 0; i < numberOfFiles - 1; i++)
{
try
{
byte[] currentData = File.ReadAllBytes(pathsToFiles[i]);
algorithm.TransformBlock(currentData, 0, currentData.Length, currentData, 0);
}
catch (Exception e)
{
throw new TimestampException("Can't calculate message digest from file: " + pathsToFiles[i], e);
}
}
try
{
byte[] lastData = File.ReadAllBytes(pathsToFiles[numberOfFiles - 1]);
algorithm.TransformFinalBlock(lastData, 0, lastData.Length);
return(algorithm.Hash);
}
catch (Exception e)
{
throw new TimestampException("Can't calculate message digest from file: " + pathsToFiles[numberOfFiles - 1], e);
}
case DataMode.HASHED_N:
int algorithmLength = hashAlgorithm.GetLength();
for (int i = 0; i < digests.Length - 1; i++)
{
algorithm.TransformBlock(digests[i], 0, digests[i].Length, digests[i], 0);
}
algorithm.TransformFinalBlock(digests[digests.Length - 1], 0, digests[digests.Length - 1].Length);
return(algorithm.Hash);
}
return(null);
}
