SignData function is detected by firewall

Hi!

I use the RSACryptoServiceProvider to sign some data. I instantiate the provider and its parameters, I read the key from a fixed string and the use the SignData function to sign the data. At the execution of SignData my firewall shows a warning that my application is trying to access a specific computer in my network. I think this computer is used as a DNS server. The SignData function waits until I allow or deny this from the firewall and then returns the results even if I press 'Deny'.

I tried to use Encrypt and Decrypt function and they do not behave this way.

Why is SignData trying to access the network

Thanks in advance,

Dimitris