Manually decode OAuth bearer token in c#

Question

In my Web Api 2.2 OWIN based application I have a situation where I manually need to decode the bearer token but I don\'t know how to do this. This is my startup.cs

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Answer 1

Just placing this here for others that may visit in the future. Solution found at https://long2know.com/2015/05/decrypting-owin-authentication-ticket/ is simpler.

Just 2 lines :

var secureDataFormat = new TicketDataFormat(new MachineKeyProtector());
AuthenticationTicket ticket = secureDataFormat.Unprotect(accessToken);



private class MachineKeyProtector : IDataProtector {
    private readonly string[] _purpose =
    {
        typeof(OAuthAuthorizationServerMiddleware).Namespace,
        "Access_Token",
        "v1"
    };

    public byte[] Protect(byte[] userData)
    {
        throw new NotImplementedException();
    }

    public byte[] Unprotect(byte[] protectedData)
    {
        return System.Web.Security.MachineKey.Unprotect(protectedData, _purpose);
    } }