An attacker watches network traffic and reads the contents of messages to ascertain details about business transactions.

An attacker watches network traffic to construct a graph of different entities that are communicating and how often they are communicating.

An attacker intercepts a communication over a network and holds onto the message until a later date when it is beneficial to the attacker to release the communication.

An attacker intercepts a message on a network and changes the data in the message before transmitting it over the network to the intended recipient.

Bob would like to be convinced that Alice sent the message.

Only Bob can read Alice’s message.

Bob would like to be sure that Alice cannot later deny having sent the message.

Bob would like an assurance that the message Alice sent is identical to the message that Bob received.