public CryptoToken( string encryptedToken, EncryptionKey encryptionKey, InitializationVector initializationVector = null )
{
_encryptionKey = encryptionKey;
if ( !string.IsNullOrEmpty( encryptedToken ) )
{
var encryptor = new SymmetricCrypto( _encryptionKey );
string plainTokenText = string.Empty;
try
{
if ( initializationVector != null )
{
byte[] encryptedValue = Convert.FromBase64String( encryptedToken );
byte[] encryptedValueAndInitializationVector = encryptedValue.Concat( initializationVector.InitializationVectorBytes ).ToArray();
plainTokenText = encryptor.Decrypt( Convert.ToBase64String( encryptedValueAndInitializationVector ) );
}
else
{
plainTokenText = encryptor.Decrypt( encryptedToken );
}
}
catch ( CryptographicException )
{
_isValid = false;
// CryptoException generally indicates the enc key/padding was wrong and that probably means someone (evil) tried to make up a crypto token.
}
catch ( FormatException )
{
_isValid = false;
// FormatException indicates that the encrypted string value provided by the user was not a Base64-encoded string
}
catch ( ArgumentNullException )
{
_isValid = false;
// ArgumentNullException indicates that something went wrong when trying to read the Cryptographic token likely due to the length being incorrect.
}
if ( _isValid )
{
DictionaryContents = JsonConvert.DeserializeObject<Dictionary<string, string>>( plainTokenText );
if ( DictionaryContents.Keys.Contains( "expirationdate" ) )
{
ExpirationDate = new DateTime( Int64.Parse( DictionaryContents["expirationdate"].ToString() ) );
DictionaryContents.Remove( "expirationdate" );
}
}
}
}
public virtual string GetEncryptedToken()
{
var tokenText = new StringBuilder();
if ( DictionaryContents != null && DictionaryContents.Count > 0 )
{
if ( !DictionaryContents.Keys.Contains("expirationdate") )
{
DictionaryContents.Add("expirationdate", ExpirationDate.Ticks.ToString());
}
tokenText = new StringBuilder( JsonConvert.SerializeObject( DictionaryContents ) );
}
var encryptor = new SymmetricCrypto( _encryptionKey );
return encryptor.Encrypt( tokenText.ToString() );
}
