private static AntiForgeryWorker CreateSingletonAntiForgeryWorker()
{
// initialize the dependency chain
// The 'Instance' property can return null, in which case we should fall back to using
// the 4.0 crypto code paths. We need to use an 'if' block rather than the null coalescing
// operator due to a CLR bug (DevDiv #424203).
ICryptoSystem cryptoSystem = MachineKey45CryptoSystem.Instance;
if (cryptoSystem == null)
{
cryptoSystem = new MachineKey40CryptoSystem();
}
IAntiForgeryConfig config = new AntiForgeryConfigWrapper();
IAntiForgeryTokenSerializer serializer = new AntiForgeryTokenSerializer(cryptoSystem);
ITokenStore tokenStore = new AntiForgeryTokenStore(config, serializer);
IClaimUidExtractor claimUidExtractor = new ClaimUidExtractor(config, ClaimsIdentityConverter.Default);
ITokenValidator tokenValidator = new TokenValidator(config, claimUidExtractor);
return new AntiForgeryWorker(serializer, config, tokenStore, tokenValidator);
}