public static byte[] UnpackAndDecrypt(byte[] hashedPassword, string purpose, Aes256CryptoBuffer key, out string keyId)
{
using (var key1 = new Aes256CryptoBuffer(key.Data))
{
key1.UnpackAndDecryptX(hashedPassword);
if (key1.MimeType != "KeyX")
{
throw new Exception("Not a KeyX.");
}
if (key1.Purpose != purpose)
{
throw new Exception("Wrong key for purpose.");
}
using (var key2 = new Aes256CryptoBuffer(key1.PlainText))
{
key2.UnpackAndDecryptX(hashedPassword);
if (key2.Id != key2.KeyId)
{
throw new Exception("Not a key.");
}
if (key2.Purpose != purpose)
{
throw new Exception("Wrong key for purpose.");
}
keyId = key2.KeyId;
var keyUnpadded = new byte[32];
Array.Copy(key2.PlainText, 0, keyUnpadded, 0, 32);
return(keyUnpadded);
}
}
}
public static Aes256CryptoBuffer UnpackAndDecrypt(byte[] hashedPassword, string purpose, Aes256CryptoBuffer key, Aes256CryptoBuffer cipherText)
{
using (var key1 = new Aes256CryptoBuffer(key.Data))
{
key1.UnpackAndDecryptX(hashedPassword);
if (key1.MimeType != "KeyX")
{
throw new Exception("Not a KeyX.");
}
if (key1.Purpose != purpose)
{
throw new Exception("Wrong key for purpose.");
}
using (var key2 = new Aes256CryptoBuffer(key1.PlainText))
{
key2.UnpackAndDecryptX(hashedPassword);
if (key2.Id != key2.KeyId)
{
throw new Exception("Not a key.");
}
if (key2.Purpose != purpose)
{
throw new Exception("Wrong key for purpose.");
}
cipherText.UnpackAndDecryptX(key2.PlainText);
return(cipherText);
}
}
}