private static ClaimsIdentity FromBase64EncodedJson(string payload)
 {
     using (var buffer = new MemoryStream(Convert.FromBase64String(payload)))
     {
         ClaimsIdentitySlim slim = (ClaimsIdentitySlim)ClaimsIdentitySerializer.Value.ReadObject(buffer);
         return(slim.ToClaimsIdentity());
     }
 }
        public static ClaimsIdentitySlim FromClaimsIdentity(ClaimsIdentity identity)
        {
            var result = new ClaimsIdentitySlim
            {
                AuthenticationType = identity.AuthenticationType,
                NameClaimType      = identity.NameClaimType,
                RoleClaimType      = identity.RoleClaimType,
                Claims             = new List <ClaimSlim>()
            };

            foreach (Claim claim in identity.Claims)
            {
                result.Claims.Add(new ClaimSlim(claim));
            }

            return(result);
        }