When Bob needs to send Alice a message with a digital signature, whose private key is used to encrypt the hash?

From center station, a train departs every 30 minutes on the fast line and a train departs every 50 minutes on the state line. if two trains depart from center station at 8: 00 a.m., one on each of the two lines, what is the next time that two trains, one on each line, will depart at the same time?

Would it be correct to say the doppler effect is the apparent change in the speed of a wave due to the motion of the source? be sure to fully explain your position using at least 3 complete content related sentences.

Which are causes of mechanical weathering? (check all that apply) a. acid rain b. plant growth c. animal actions d. carbon dioxide e. pressure release i chose b & e and got the question wrong.