private static void _CheckSecurEntityID(bool read, SecurEntity se)
{
if (false == read)
{
long pk = Convert.ToInt64(se.GetType().GetProperty(se.GetPrimaryKeyPropertyName()).GetValue(se, null));
if (pk == 0)
{
//
// N.B. - this library assumes that the Primary Key of any
// SecurEntity is of type int. However, since that value
// is generated automatically by SQL the first time the
// object/row is written, it can't be used in the hash
// computation.
//
// Instead, this GUID property is used in order to support
// the cryptographic binding of relationships between
// SecurEntity objects.
//
if (se.SecurEntityID == Guid.Empty)
{
se.SecurEntityID = Guid.NewGuid();
}
}
}
else if (se.SecurEntityID == Guid.Empty)
{
throw new Exception("SecurEntity integrity verification failed.");
}
}
private void _AddProperties(bool read, ref CryptoHelper ch)
{
PropertyInfo[] sourcePropertyInfos = GetType().GetProperties(BindingFlags.Instance | BindingFlags.Public);
List <PropertyInfo> filteredPropertyInfos = new List <PropertyInfo>();
//
// Check if this appears to be a brand new object
//
_CheckSecurEntityID(read, this);
//
// Filter out the unsupported property types
//
for (int i = 0; i < sourcePropertyInfos.Length; i++)
{
bool colIsStringType;
if (_IsPropertyForIntegrity(sourcePropertyInfos[i], out colIsStringType))
{
filteredPropertyInfos.Add(sourcePropertyInfos[i]);
}
}
//
// Sort the filtered property list to ensure that the same field
// order is always used for the following cryptographic operations
//
filteredPropertyInfos.Sort(ComparePropertyInfos);
//
// Iterate again through the supported property types
//
for (int i = 0; i < filteredPropertyInfos.Count; i++)
{
//
// Turn the property into a byte array
//
MemoryStream ms = new MemoryStream();
BinaryWriter bw = new BinaryWriter(ms);
object o = filteredPropertyInfos[i].GetValue(this, null);
SecurEntity se = o as SecurEntity;
if (se != null)
{
_CheckSecurEntityID(read, se);
bw.Write(se.SecurEntityID.ToString());
}
else
{
bw.Write(null == o ? "" : o.ToString());
}
bw.Close();
//
// Determine whether to encrypt, decrypt, or neither
//
string plaintext = null;
string ciphertext = null;
CryptoHelper.AddDataAction action;
if (_IsPropertyForEncryption(filteredPropertyInfos[i]))
{
if (read)
{
action = CryptoHelper.AddDataAction.Decrypt;
ciphertext = (string)o;
}
else
{
action = CryptoHelper.AddDataAction.Encrypt;
}
}
else
{
action = CryptoHelper.AddDataAction.DoNothing;
}
//
// Perform the required crypto
//
ch.AddData(
ms.ToArray(),
action,
i == filteredPropertyInfos.Count - 1,
ref plaintext,
ref ciphertext);
//
// Set the encrypted or decrypted property, if appropriate
//
switch (action)
{
case CryptoHelper.AddDataAction.Decrypt:
filteredPropertyInfos[i].SetValue(this, plaintext, null);
break;
case CryptoHelper.AddDataAction.Encrypt:
filteredPropertyInfos[i].SetValue(this, ciphertext, null);
break;
}
}
}
