/// <summary>
///
/// </summary>
/// <param name="secretKey"></param>
/// <param name="plainData"></param>
/// <returns></returns>
public static ProtectedMemory EncryptData(ProtectedString secretKey, ProtectedMemory plainData)
{
ProtectedMemory returnValue = null;
System.Byte[] encryptedData = null;
#region Check protection of secret key
if (!secretKey.IsProtected)
{
throw new UnsecureException();
}
#endregion
#region Check protection of plain data
if (!plainData.IsProtected)
{
throw new UnsecureException();
}
#endregion
#region Prepare encryption provider
// Unprotect memory containing secret key
secretKey.Unprotect();
// Create encryption provider
System.Security.Cryptography.SymmetricAlgorithm encryptionProvider = System.Security.Cryptography.Aes.Create();
encryptionProvider.Mode = System.Security.Cryptography.CipherMode.CBC;
encryptionProvider.Key = secretKey.GetBytes();
encryptionProvider.GenerateIV();
// Reprotect memory containing secret key
secretKey.Protect();
#endregion
// Create encryptor
System.Security.Cryptography.ICryptoTransform encryptor = encryptionProvider.CreateEncryptor(encryptionProvider.Key, encryptionProvider.IV);
// Create handle to stream data into memory
using (System.IO.MemoryStream memoryStream = new System.IO.MemoryStream())
{
// Write IV to temp memory (IV length is static => 16 )
memoryStream.Write(encryptionProvider.IV, 0, 16);
// Create handle for data encryption; data streamed to this stream will be automatically encrypted and streamed to memory
using (System.Security.Cryptography.CryptoStream cryptoStream = new System.Security.Cryptography.CryptoStream(memoryStream, encryptor, System.Security.Cryptography.CryptoStreamMode.Write))
{
// Create handle to write data to a stream; data written to this stream will be automatically encrypted and streamed to memory
using (System.IO.StreamWriter streamWriter = new System.IO.StreamWriter(cryptoStream))
{
// Unprotect plain data
plainData.Unprotect();
#region Write and encrypt plain data to temp memory
foreach (System.Byte b in plainData.GetBytes())
{
streamWriter.Write((System.Char)b);
}
#endregion
// Reprotect plain data
plainData.Protect();
}
}
// Save content of temp memory in temp buffer
encryptedData = memoryStream.ToArray();
}
// Dispose encryptor
encryptor.Dispose();
// Dispose encryption provider
encryptionProvider.Dispose();
#region Save cyphered data in protected memory
// Create protected memory for cyphered data
returnValue = new ProtectedMemory(encryptedData.Length);
// Unprotect memory for cyphered data
returnValue.Unprotect();
// Copy cyphered data in encrypted memory
for (System.Int32 i = 0; i < encryptedData.Length; i++)
{
returnValue.SetByte(i, encryptedData[i]);
}
// Reprotect memory with cyphered data
returnValue.Protect();
#endregion
return(returnValue);
}
public override void GenerateIV()
{
_symmetricAlgorithm.GenerateIV();
}
