Which process is used by receivers in a GPS system to calculate the distance between themselves and the satellites to determine their location?

What action is required to establish a VPC VPN connection between an on-premises data center and an Amazon VPC virtual private gateway?

A. Modify the main route table to allow traffic to a network address translation instance. B. Use a dedicated network address translation instance in the public subnet. C. Assign a static Internet-routable IP address to an Amazon VPC customer gateway. D. Establish a dedicated networking connection using AWS Direct Connect.

Two parties wish to exchange encrypted messages using symmetric key cryptography. The parties do not have an out-of-band method for exchanging keys. The parties should use:

a. A stream cipher b. Message digests c. Public key cryptography d. Diffie-Hellman key exchange