Criptografia no AES no Windows 8

gistfile1.cs

private static readonly byte[] iv = // array of 16 bytes

        public static string Encrypt(string message, string password)
        {
            var algorithm = SymmetricKeyAlgorithmProvider.OpenAlgorithm(SymmetricAlgorithmNames.AesCbcPkcs7);
            var key = algorithm.CreateSymmetricKey(Encoding.UTF8.GetBytes(password).AsBuffer());
            var encrypted = CryptographicEngine.Encrypt(key, Encoding.UTF8.GetBytes(message).AsBuffer(), iv.AsBuffer());

            return CryptographicBuffer.EncodeToBase64String(encrypted);
        }

        public static string Decrypt(string message, string password)
        {
            var algorithm = SymmetricKeyAlgorithmProvider.OpenAlgorithm(SymmetricAlgorithmNames.AesCbcPkcs7);
            var key = algorithm.CreateSymmetricKey(Encoding.UTF8.GetBytes(password).AsBuffer());

            var encrypted = CryptographicEngine.Decrypt(key, Convert.FromBase64String(message).AsBuffer(), iv.AsBuffer());

            return CryptographicBuffer.ConvertBinaryToString( BinaryStringEncoding.Utf8,  encrypted);
        }