private bool IsHashValid()
{
// first, validate the actual hash chosen
bool valid = comboBoxHash.Items.Contains(comboBoxHash.Text);
// second, for keyed hash algorithms only, validate the key
using (System.Security.Cryptography.HashAlgorithm hash = System.Security.Cryptography.HashAlgorithm.Create(comboBoxHash.Text))
{
if (hash != null)
{
if (hash.GetType().IsSubclassOf(typeof(System.Security.Cryptography.KeyedHashAlgorithm)))
{
byte[] key = System.Text.Encoding.ASCII.GetBytes(textBoxHashKey.Text);
// MACTripleDES is a special case that only accepts a key that is 16 or 20 bytes long
// and must not be "weak" as determined by the library
if (hash is System.Security.Cryptography.MACTripleDES)
{
valid = (key.Length == 16 || key.Length == 24) && !System.Security.Cryptography.TripleDES.IsWeakKey(key);
}
// all other keyed hashes only require non empty keys
else
{
valid = !string.IsNullOrEmpty(textBoxHashKey.Text);
}
}
}
else
{
valid = false;
}
}
return(valid);
}
//TODO: probably use elsewhere but careful of the using
private bool IsHashAlgorithm(string hash)
{
bool isHashAlgorithm = false;
// set the state of the key text box based on whether a keyed hash has been selected
using (System.Security.Cryptography.HashAlgorithm hashAlgorithm = System.Security.Cryptography.HashAlgorithm.Create(hash))
{
//System.Security.Cryptography.KeyedHashAlgorithm keyedHash = hash as System.Security.Cryptography.KeyedHashAlgorithm;
//if (keyedHash != null) //TODO: test performance
isHashAlgorithm = (hashAlgorithm.GetType().IsSubclassOf(typeof(System.Security.Cryptography.KeyedHashAlgorithm)));
}
return(isHashAlgorithm);
}
private void HashBackgroundWorker_DoWork(object sender, DoWorkEventArgs e)
{
// Do not access the form's BackgroundWorker reference directly.
// Instead, use the reference provided by the sender parameter.
BackgroundWorker bw = sender as BackgroundWorker;
List <object> arguments = e.Argument as List <object>;
List <string> filesToHash = new List <string>();
// retrieve all files to hash from user input
string[] list = ((string)arguments[0]).Split(';');
foreach (string fileOrDirectory in list)
{
if (System.IO.Directory.Exists(fileOrDirectory))
{
filesToHash.AddRange(System.IO.Directory.GetFiles(fileOrDirectory.Trim(), "*", (System.IO.SearchOption)arguments[3]));
}
else if (System.IO.File.Exists(fileOrDirectory))
{
filesToHash.Add(fileOrDirectory.Trim());
}
}
// report the number of files to support the progress bar limits
bw.ReportProgress(0, filesToHash.Count);
using (System.Security.Cryptography.HashAlgorithm hash = System.Security.Cryptography.HashAlgorithm.Create((string)arguments[1]))
{
// if using a keyed hash, set the key before computing the hash
if (hash.GetType().IsSubclassOf(typeof(System.Security.Cryptography.KeyedHashAlgorithm)))
{
byte[] key = System.Text.Encoding.ASCII.GetBytes((string)arguments[2]);
((System.Security.Cryptography.KeyedHashAlgorithm)hash).Key = key;
}
foreach (string file in filesToHash)
{
if (bw.CancellationPending)
{
hashResults.Add(file, "Cancelled");
e.Cancel = true;
break;
}
hashResults.Add(file, HashFile(file, hash));
bw.ReportProgress(0);
}
}
}
