Search for embedded and encrypted objects in QR-Code signatures Leave feedback

/// <summary>
/// Creates class that implements IDataSerializer interface
/// It cam support common serialization like JSon or custom data format
/// </summary>
class CustomSerializationAttribute : Attribute, IDataSerializer
{
    public T Deserialize<T>(string source) where T : class
    {
        DocumentSignatureData result = new DocumentSignatureData();
        byte[] bytes = Encoding.UTF8.GetBytes(source);
        using (MemoryStream stream = new MemoryStream(bytes))
        {
            stream.Seek(0, SeekOrigin.Begin);
            using (BinaryReader reader = new BinaryReader(stream))
            {
                result.ID = reader.ReadString();
                result.Author = reader.ReadString();
                result.Signed = new DateTime( reader.ReadInt64());
                result.DataFactor = reader.ReadDecimal();
            }
        }
        var converter = TypeDescriptor.GetConverter(typeof(T));
        return (T)converter.ConvertFrom(result);
    }
    public string Serialize(object data)
    {
        string result = string.Empty;
        DocumentSignatureData signatureData = data as DocumentSignatureData;
        if (signatureData != null)
        {
            using (MemoryStream stream = new MemoryStream())
            {
                using (BinaryWriter writer = new BinaryWriter(stream))
                {
                    writer.Write(signatureData.ID);
                    writer.Write(signatureData.Author);
                    writer.Write(signatureData.Signed.Ticks);
                    writer.Write(signatureData.DataFactor);
                }
                result = Encoding.UTF8.GetString(stream.ToArray());
            }
        }
        return result;
    }
}

// Define class that implements IDataEncryption interface
private class CustomXOREncryptionAttribute : Attribute, IDataEncryption
{
    /// <summary>
    /// Gets or sets non empty key for encryption (at least one character)
    /// </summary>
    public int Key { get; set; }
    /// <summary>
    /// Encode method to encrypt string.
    /// </summary>
    /// <param name="source">Source string to encode.</param>
    /// <returns>Returns enccrypted string</returns>
    public string Encode(string source)
    {
        return Process(source);
    }
    /// <summary>
    /// Decode method to obtain decrypted string.
    /// </summary>
    /// <param name="source">Source string to decode.</param>
    /// <returns>Returns decrypted string</returns>
    public string Decode(string source)
    {
        return Process(source);
    }
    /// <summary>
    /// Using XOR operation get encoded / decoded string
    /// </summary>
    /// <param name="source"></param>
    /// <returns></returns>
    private string Process(string source)
    {
        StringBuilder src = new StringBuilder(source);
        StringBuilder dst = new StringBuilder(src.Length);
        char chTmp;
        for (int index = 0; index < src.Length; ++index)
        {
            chTmp = src[index];
            chTmp = (char)(chTmp ^ this.Key);
            dst.Append(chTmp);
        }
        return dst.ToString();
    }
}

// setup CustomSerialization Attribute to setup customer serialization(see example above)
[CustomSerialization]
// setup CustomXOREncryption Attribute for custom encryption (see example above)
[CustomXOREncryption]
private class DocumentSignatureData
{
    [Format("SignID")]
    public string ID { get; set; }
    [Format("SAuth")]
    public string Author { get; set; }
    [Format("SDate", "yyyy-MM-dd")]
    public DateTime Signed { get; set; }
    [Format("SDFact", "N2")]
    public decimal DataFactor { get; set; }
    [SkipSerialization]
    public string Comments { get; set; }
}