public static byte[] Decrypt(byte[] cipherTextBytes, byte[] entropyBytes, out string description)
{
DATA_BLOB pPlainText = new DATA_BLOB();
DATA_BLOB dataBlob1 = new DATA_BLOB();
DATA_BLOB dataBlob2 = new DATA_BLOB();
CRYPTPROTECT_PROMPTSTRUCT cryptprotectPromptstruct = new CRYPTPROTECT_PROMPTSTRUCT();
DataProtection.InitPrompt(ref cryptprotectPromptstruct);
description = string.Empty;
try
{
try
{
DataProtection.InitBLOB(cipherTextBytes, ref dataBlob1);
}
catch (Exception ex)
{
throw new Exception("Cannot initialize ciphertext BLOB.", ex);
}
try
{
DataProtection.InitBLOB(entropyBytes, ref dataBlob2);
}
catch (Exception ex)
{
throw new Exception("Cannot initialize entropy BLOB.", ex);
}
int dwFlags = 1;
if (!Advent.Common.Interop.NativeMethods.CryptUnprotectData(ref dataBlob1, ref description, ref dataBlob2, IntPtr.Zero, ref cryptprotectPromptstruct, dwFlags, ref pPlainText))
{
throw new Exception("CryptUnprotectData failed.", (Exception) new Win32Exception(Marshal.GetLastWin32Error()));
}
byte[] destination = new byte[pPlainText.cbData];
Marshal.Copy(pPlainText.pbData, destination, 0, pPlainText.cbData);
return(destination);
}
catch (Exception ex)
{
throw new Exception("Unable to decrypt data.", ex);
}
finally
{
if (pPlainText.pbData != IntPtr.Zero)
{
Marshal.FreeHGlobal(pPlainText.pbData);
}
if (dataBlob1.pbData != IntPtr.Zero)
{
Marshal.FreeHGlobal(dataBlob1.pbData);
}
if (dataBlob2.pbData != IntPtr.Zero)
{
Marshal.FreeHGlobal(dataBlob2.pbData);
}
}
}
private static void InitBLOB(byte[] data, ref DATA_BLOB blob)
{
if (data == null)
{
data = new byte[0];
}
blob.pbData = Marshal.AllocHGlobal(data.Length);
if (blob.pbData == IntPtr.Zero)
{
throw new Exception("Unable to allocate data buffer for BLOB structure.");
}
blob.cbData = data.Length;
Marshal.Copy(data, 0, blob.pbData, data.Length);
}
public static extern bool CryptUnprotectData(ref DATA_BLOB pCipherText, ref string pszDescription, ref DATA_BLOB pEntropy, IntPtr pReserved, ref CRYPTPROTECT_PROMPTSTRUCT pPrompt, int dwFlags, ref DATA_BLOB pPlainText);
public static byte[] Encrypt(DataProtection.KeyType keyType, byte[] plainTextBytes, byte[] entropyBytes, string description)
{
if (plainTextBytes == null)
{
plainTextBytes = new byte[0];
}
if (entropyBytes == null)
{
entropyBytes = new byte[0];
}
if (description == null)
{
description = string.Empty;
}
DATA_BLOB dataBlob1 = new DATA_BLOB();
DATA_BLOB pCipherText = new DATA_BLOB();
DATA_BLOB dataBlob2 = new DATA_BLOB();
CRYPTPROTECT_PROMPTSTRUCT cryptprotectPromptstruct = new CRYPTPROTECT_PROMPTSTRUCT();
DataProtection.InitPrompt(ref cryptprotectPromptstruct);
try
{
try
{
DataProtection.InitBLOB(plainTextBytes, ref dataBlob1);
}
catch (Exception ex)
{
throw new Exception("Cannot initialize plaintext BLOB.", ex);
}
try
{
DataProtection.InitBLOB(entropyBytes, ref dataBlob2);
}
catch (Exception ex)
{
throw new Exception("Cannot initialize entropy BLOB.", ex);
}
int dwFlags = 1;
if (keyType == DataProtection.KeyType.MachineKey)
{
dwFlags |= 4;
}
if (!Advent.Common.Interop.NativeMethods.CryptProtectData(ref dataBlob1, description, ref dataBlob2, IntPtr.Zero, ref cryptprotectPromptstruct, dwFlags, ref pCipherText))
{
throw new Exception("CryptProtectData failed.", (Exception) new Win32Exception(Marshal.GetLastWin32Error()));
}
byte[] destination = new byte[pCipherText.cbData];
Marshal.Copy(pCipherText.pbData, destination, 0, pCipherText.cbData);
return(destination);
}
catch (Exception ex)
{
throw new Exception("DPAPI was unable to encrypt data.", ex);
}
finally
{
if (dataBlob1.pbData != IntPtr.Zero)
{
Marshal.FreeHGlobal(dataBlob1.pbData);
}
if (pCipherText.pbData != IntPtr.Zero)
{
Marshal.FreeHGlobal(pCipherText.pbData);
}
if (dataBlob2.pbData != IntPtr.Zero)
{
Marshal.FreeHGlobal(dataBlob2.pbData);
}
}
}