private byte[] InternalComputeHash(string password)
{
if (password == null)
{
throw new ArgumentNullException("password");
}
//prepare password, padding to 14 bytes if not enough, otherwise cutting the part exceeding 14 bytes
password = password.ToUpper();
byte[] passwordBuffer;
if (password.Length > lmHashPasswordLength)
{
passwordBuffer = Encoding.ASCII.GetBytes(password.ToCharArray(), 0, lmHashPasswordLength);
}
else
{
byte[] temp = Encoding.ASCII.GetBytes(password);
passwordBuffer = new byte[lmHashPasswordLength];
Array.Copy(temp, passwordBuffer, temp.Length);
}
//insert zero ervery 7 bits to generate two keys used in Des encrypt
byte[] password1 = GenerateDesKey(passwordBuffer, 0);
//get the key starting from half of passwordArray's length position.
byte[] password2 = GenerateDesKey(passwordBuffer, passwordBuffer.Length / 2);
//use Des with ECB CipherMode and NONE padding option to encrypt "KGS!@#$%"
byte[] hashDataBuffer = Encoding.ASCII.GetBytes(this.lmHashData);
DESCryptoServiceProvider des = new DESCryptoServiceProvider();
des.Mode = CipherMode.ECB;
des.Padding = PaddingMode.None;
// DES class performs weak key check so that some short-length keys may fail
// We call its method to create ICryptoTransform directly to bypass the check.
const string methodName = "_NewEncryptor";
object[] desParams = new object[] { password1, des.Mode, null, des.FeedbackSize, 0 };
ICryptoTransform ct1 = (ICryptoTransform)ObjectUtility.InvokeMethod(des, methodName, desParams);
byte[] hash1 = ct1.TransformFinalBlock(hashDataBuffer, 0, hashDataBuffer.Length);
desParams[0] = password2;
ICryptoTransform ct2 = (ICryptoTransform)ObjectUtility.InvokeMethod(des, methodName, desParams);
byte[] hash2 = ct2.TransformFinalBlock(hashDataBuffer, 0, hashDataBuffer.Length);
//concatenate the two encrypted text to one.
byte[] ConcatenatedArray = Helper.ConcatenateByteArrays(hash1, hash2);
return(ConcatenatedArray);
}
