see http://bertcraven.wordpress.com/2011/03/27/implementing-a-rest-ful-service-using-openrasta-and-oauth-wrap-with-windows-azure-appfabric-acs/

RequiresClaimsAttribute.cs

namespace AzureClaimsAuthenticator
{
	using System;

	[AttributeUsage(AttributeTargets.Method)]
	public class RequiresClaimsAttribute : Attribute
	{
		public string ClaimType { get; set; }

		public string ClaimValue { get; set; }

		public RequiresClaimsAttribute(string claimType, string claimValue)
		{
			this.ClaimType = claimType;
			this.ClaimValue = claimValue;
		}
	}
}