public byte[] Unprotect(byte[] protectedData)
{
protectedData = protectedData.UnGZip();
var cacheKey = protectedData.ToBase64String();
return(CachedDecrptedData.GetOrAdd(cacheKey, (key) =>
{
var keyLength = protectedData.First();
var encryptionKeyReference = protectedData.Skip(1).Take(keyLength).ToArray();
var dataPart = protectedData.Skip(1 + keyLength).ToArray();
var encryptionKey = DataKeyService.GetEncryptionKey(encryptionKeyReference);
return CreateProtector(encryptionKey).Unprotect(dataPart);
}));
}
public byte[] Protect(byte[] plaintext)
{
var key = Task.Factory.RunSync(() => DataKeyService.GenerateKey());
var encryptedData = CreateProtector(key.EncryptionKey).Protect(plaintext);
// To make it secure, we should combine the key's length, the key and the cipher data.
var cipher = key.EncryptionKeyReference;
if (cipher.Length > byte.MaxValue)
{
throw new Exception("Cipher key is longer than a byte!");
}
return(new byte[] { (byte)cipher.Length }
.Concat(cipher, encryptedData).ToArray().GZip());
}
