Providing acknowledgments from receiver to sender is a control that helps to ensure that transaction data reaches its destination, as it confirms the successful delivery of the data and allows the sender to resend the data in case of failure. Securing the network from attacks, digitally signing individual messages, and encrypting data-in-transit are controls that help to ensure the integrity and confidentiality of the data, but not the availability or delivery of the data. References = CRISC by Isaca Actual Free Exam Q&As, question 199.