/* Reconstructs secret from first "k" share files from the array of file locations (ShareFilesNames)
* then writes the secret into SecretFileLocation */
//TODO : Handle file I/O exceptions
//TODO : Filter only .share files?
public static void ReconstructFileSecret(string[] ShareFilesLocations, byte k, string SecretFileLocation, byte[] key)
{
if (ShareFilesLocations.Length == 0 || k == 0)
{
throw new System.ArgumentException("Share file locations cannot be empty and k cannot be 0", "ShareFilesNames and k");
}
if (ShareFilesLocations.Length < k)
{
throw new System.ArgumentException("The number of Share files cannot be less than k", "ShareFilesNames and k");
}
try
{
Share[][] Shares = new Share[k][];
//reading file to shares
for (int i = 0; i < k; i++)
{
using (FileStream fs = new FileStream(ShareFilesLocations[i], FileMode.Open, FileAccess.Read))
{
byte X = (byte)i; //default value
Share[] CurShares = new Share[fs.Length - 1];
for (int j = 0; j < fs.Length; j++)
{
//getting the x value in front of the file
if (j == 0)
{
X = (byte)fs.ReadByte();
}
//convert the rest of file to Share
else
{
CurShares[j - 1] = new Share((Field)X, (Field)fs.ReadByte());
}
}
Shares[i] = CurShares;
}
}
//reconstruction process
Field[] Secret = new Field[Shares[0].Length];
byte[] SecretBytes = new byte[Secret.Length];
for (int i = 0; i < Shares[0].Length; i++)
{
Share[] CurShares = new Share[k];
for (int j = 0; j < k; j++)
{
CurShares[j] = Shares[j][i];
}
Secret[i] = ReconstructSecret(CurShares, k);
SecretBytes[i] = (byte)Secret[i];
}
SecretBytes = AESDecryptBytes(SecretBytes, key);
//writing secret to file
using (FileStream fsWrite = new FileStream(SecretFileLocation, FileMode.Create, FileAccess.Write))
{
fsWrite.Write(SecretBytes, 0, SecretBytes.Length);
}
}
catch (Exception e)
{
Console.WriteLine(e.ToString());
}
}
public Share(Share S)
{
t = new Tuple <Field, Field>(S.GetX(), S.GetY());
}