Question

这与how to generate a unique token which expires after 24 hours?

直接相关

我试图做的是嵌入以下内容：

页码（0到6）
UTC格式的当前日期/时间戳
和唯一GUID

到目前为止我的代码是：

private string GenerateToken(Int32 pageNumber)
{
    byte[] currentTimeStamp = BitConverter.GetBytes(DateTime.UtcNow.ToBinary());
    byte[] key = Guid.NewGuid().ToByteArray();
    byte[] newPageNumber = BitConverter.GetBytes(pageNumber);
    string token = Convert.ToBase64String(newPageNumber.Concat(currentTimeStamp).Concat(key).ToArray());
    return token;
}

private tokenClass TokenAuthenticates(string token)
{
    byte[] data = Convert.FromBase64String(token);

    tokenClass _token = new tokenClass()
    {
        PageNumber = 0,
        TokenDateTimeStamp = DateTime.FromBinary(BitConverter.ToInt64(data, 1)),
        TokenKey = new Guid(),
        Validates = (DateTime.FromBinary(BitConverter.ToInt64(data, 1)) < DateTime.UtcNow.AddHours(-2))
    };

    return _token;
}

解码器中的页面和Guid参数还没有找到，所以它们基本上都是假的。

我需要做些什么来完成这项工作？

Answer 1

像这样生成你的令牌：

private static string GenerateToken(Int32 pageNumber)
{
    byte[] currentTimeStamp = BitConverter.GetBytes(DateTime.UtcNow.ToBinary());
    var keyGuid = Guid.NewGuid();
    byte[] key = keyGuid.ToByteArray();
    byte[] newPageNumber = BitConverter.GetBytes(pageNumber);

    // date plus page number plus key
    string token = Convert.ToBase64String(currentTimeStamp.Concat(newPageNumber).Concat(key).ToArray());
    return token;
}

像这样阅读令牌（在TokenAuthenticates方法中）：

byte[] data = Convert.FromBase64String(token);

// It will take eight bytes starting at index 0
DateTime when = DateTime.FromBinary(BitConverter.ToInt64(data, 0)); 

// 8 first bytes was taken by date so lets skip 8 and then take 4 since page number is an integer and takes 4 bytes
int pageNumber = BitConverter.ToInt32(data.Skip(8).Take(4).ToArray(), 0);

// 8 bytes for date + 4 bytes for page number so we skip 12 and then take 16 for Guid
// Guid can be generated directly from the bytes
Guid key = new Guid(data.Skip(12).Take(16).ToArray());

这是一种方法，因此您无需对数字进行硬编码或确定尺寸。使用sizeof运算符为您做出决定：

int pageNumber = BitConverter.ToInt32(data.Skip(sizeof(long))
                     .Take(sizeof(int)).ToArray(), 0);

// Skip date and pageNumber, the rest is Guid
Guid key = new Guid(data.Skip(sizeof(long) + sizeof(int)).ToArray());

我会调用方法AuthenticateToken，因为它是一个动词动词，听起来更清晰可读。您可以在阅读令牌后执行进一步的验证。您也可以考虑加密令牌。

如何从Base64String中提取特定数据？

1 个答案: