private static unsafe byte[] ExportPkcs8KeyBlob(
SafeNCryptKeyHandle keyHandle,
string password,
int kdfCount)
{
var pbeParams = new NativeMethods.NCrypt.PbeParams();
NativeMethods.NCrypt.PbeParams *pbeParamsPtr = &pbeParams;
var salt = new byte[NativeMethods.NCrypt.PbeParams.RgbSaltSize];
RandomNumberGenerator.GetBytes(salt);
pbeParams.Params.cbSalt = salt.Length;
Marshal.Copy(salt, 0, (IntPtr)pbeParams.rgbSalt, salt.Length);
pbeParams.Params.iIterations = kdfCount;
var keyName = Guid.NewGuid().ToString("D");
fixed(char *passwordPtr = password)
fixed(char *keyNamePtr = keyName)
fixed(byte *oidPtr = s_pkcs12TripleDesOidBytes)
{
NativeMethods.NCrypt.NCryptBuffer *buffers =
stackalloc NativeMethods.NCrypt.NCryptBuffer[3];
buffers[0] = new NativeMethods.NCrypt.NCryptBuffer
{
BufferType = NativeMethods.NCrypt.BufferType.PkcsSecret,
cbBuffer = checked (2 * (password.Length + 1)),
pvBuffer = (IntPtr)passwordPtr,
};
if (buffers[0].pvBuffer == IntPtr.Zero)
{
buffers[0].cbBuffer = 0;
}
buffers[1] = new NativeMethods.NCrypt.NCryptBuffer
{
BufferType = NativeMethods.NCrypt.BufferType.PkcsAlgOid,
cbBuffer = s_pkcs12TripleDesOidBytes.Length,
pvBuffer = (IntPtr)oidPtr,
};
buffers[2] = new NativeMethods.NCrypt.NCryptBuffer
{
BufferType = NativeMethods.NCrypt.BufferType.PkcsAlgParam,
cbBuffer = sizeof(NativeMethods.NCrypt.PbeParams),
pvBuffer = (IntPtr)pbeParamsPtr,
};
var desc = new NativeMethods.NCrypt.NCryptBufferDesc
{
cBuffers = 3,
pBuffers = (IntPtr)buffers,
ulVersion = 0,
};
int result = NativeMethods.NCrypt.NCryptExportKey(
keyHandle,
IntPtr.Zero,
NCRYPT_PKCS8_PRIVATE_KEY_BLOB,
ref desc,
null,
0,
out int bytesNeeded,
0);
if (result != 0)
{
throw new Win32Exception(result);
}
byte[] exported = new byte[bytesNeeded];
result = NativeMethods.NCrypt.NCryptExportKey(
keyHandle,
IntPtr.Zero,
NCRYPT_PKCS8_PRIVATE_KEY_BLOB,
ref desc,
exported,
exported.Length,
out bytesNeeded,
0);
if (result != 0)
{
throw new Win32Exception(result);
}
if (bytesNeeded != exported.Length)
{
Array.Resize(ref exported, bytesNeeded);
}
NativeMethods.NCrypt.NCryptOpenStorageProvider(
out var safeNCryptProviderHandle,
MicrosoftSoftwareKeyStorageProvider,
0);
NativeMethods.NCrypt.NCryptBuffer *buffers2 =
stackalloc NativeMethods.NCrypt.NCryptBuffer[4];
buffers2[0] = new NativeMethods.NCrypt.NCryptBuffer
{
BufferType = NativeMethods.NCrypt.BufferType.PkcsSecret,
cbBuffer = checked (2 * (password.Length + 1)),
pvBuffer = (IntPtr)passwordPtr,
};
if (buffers2[0].pvBuffer == IntPtr.Zero)
{
buffers2[0].cbBuffer = 0;
}
buffers2[1] = new NativeMethods.NCrypt.NCryptBuffer
{
BufferType = NativeMethods.NCrypt.BufferType.PkcsAlgOid,
cbBuffer = s_pkcs12TripleDesOidBytes.Length,
pvBuffer = (IntPtr)oidPtr,
};
buffers2[2] = new NativeMethods.NCrypt.NCryptBuffer
{
BufferType = NativeMethods.NCrypt.BufferType.PkcsAlgParam,
cbBuffer = sizeof(NativeMethods.NCrypt.PbeParams),
pvBuffer = (IntPtr)pbeParamsPtr,
};
buffers2[3] = new NativeMethods.NCrypt.NCryptBuffer
{
BufferType = NativeMethods.NCrypt.BufferType.PkcsKeyName,
cbBuffer = checked (2 * (keyName.Length + 1)),
pvBuffer = (IntPtr)keyNamePtr,
};
var desc2 = new NativeMethods.NCrypt.NCryptBufferDesc
{
cBuffers = 4,
pBuffers = (IntPtr)buffers2,
ulVersion = 0,
};
result = NativeMethods.NCrypt.NCryptImportKey(
safeNCryptProviderHandle,
IntPtr.Zero,
NCRYPT_PKCS8_PRIVATE_KEY_BLOB,
ref desc2,
out var safeNCryptKeyHandle,
exported,
exported.Length,
NCRYPT_DO_NOT_FINALIZE_FLAG);
if (result != 0)
{
throw new Win32Exception(result);
}
var exportPolicyBytes = BitConverter.GetBytes(
(int)(CngExportPolicies.AllowExport |
CngExportPolicies.AllowPlaintextExport |
CngExportPolicies.AllowArchiving |
CngExportPolicies.AllowPlaintextArchiving));
NativeMethods.NCrypt.NCryptSetProperty(
safeNCryptKeyHandle,
"Export Policy",
exportPolicyBytes,
exportPolicyBytes.Length,
CngPropertyOptions.Persist);
NativeMethods.NCrypt.NCryptFinalizeKey(
safeNCryptKeyHandle,
0);
using (var key2 = CngKey.Open(keyName))
{
Trace.WriteLine(key2.ExportPolicy);
var plainTextBytes =
key2.Export(CngKeyBlobFormat.Pkcs8PrivateBlob);
key2.Delete();
return(plainTextBytes);
}
}
}
private static unsafe byte[] ExportEncryptedPkcs8(
CngKey cngKey,
string password,
int kdfCount)
{
var pbeParams = new NativeMethods.NCrypt.PbeParams();
NativeMethods.NCrypt.PbeParams *pbeParamsPtr = &pbeParams;
byte[] salt = new byte[NativeMethods.NCrypt.PbeParams.RgbSaltSize];
using (RandomNumberGenerator rng = RandomNumberGenerator.Create())
{
rng.GetBytes(salt);
}
pbeParams.Params.cbSalt = salt.Length;
Marshal.Copy(salt, 0, (IntPtr)pbeParams.rgbSalt, salt.Length);
pbeParams.Params.iIterations = kdfCount;
fixed(char *stringPtr = password)
fixed(byte *oidPtr = s_pkcs12TripleDesOidBytes)
{
NativeMethods.NCrypt.NCryptBuffer *buffers =
stackalloc NativeMethods.NCrypt.NCryptBuffer[3];
buffers[0] = new NativeMethods.NCrypt.NCryptBuffer
{
BufferType = NativeMethods.NCrypt.BufferType.PkcsSecret,
cbBuffer = checked (2 * (password.Length + 1)),
pvBuffer = (IntPtr)stringPtr,
};
if (buffers[0].pvBuffer == IntPtr.Zero)
{
buffers[0].cbBuffer = 0;
}
buffers[1] = new NativeMethods.NCrypt.NCryptBuffer
{
BufferType = NativeMethods.NCrypt.BufferType.PkcsAlgOid,
cbBuffer = s_pkcs12TripleDesOidBytes.Length,
pvBuffer = (IntPtr)oidPtr,
};
buffers[2] = new NativeMethods.NCrypt.NCryptBuffer
{
BufferType = NativeMethods.NCrypt.BufferType.PkcsAlgParam,
cbBuffer = sizeof(NativeMethods.NCrypt.PbeParams),
pvBuffer = (IntPtr)pbeParamsPtr,
};
var desc = new NativeMethods.NCrypt.NCryptBufferDesc
{
cBuffers = 3,
pBuffers = (IntPtr)buffers,
ulVersion = 0,
};
using (var keyHandle = cngKey.Handle)
{
int result = NativeMethods.NCrypt.NCryptExportKey(
keyHandle,
IntPtr.Zero,
NCRYPT_PKCS8_PRIVATE_KEY_BLOB,
ref desc,
null,
0,
out int bytesNeeded,
0);
if (result != 0)
{
throw new Win32Exception(result);
}
byte[] exported = new byte[bytesNeeded];
result = NativeMethods.NCrypt.NCryptExportKey(
keyHandle,
IntPtr.Zero,
NCRYPT_PKCS8_PRIVATE_KEY_BLOB,
ref desc,
exported,
exported.Length,
out bytesNeeded,
0);
if (result != 0)
{
throw new Win32Exception(result);
}
if (bytesNeeded != exported.Length)
{
Array.Resize(ref exported, bytesNeeded);
}
return(exported);
}
}
}