Alice is retiring from her esteemed career at the department of hypothetical cryptography. Whilst she wishes to concentrate on simpler things she would prefer to keep in touch with her colleague Bob with whom she shared many a meaningless – and variably authenticated – conversation. Having left her interest in asymmetric keys and MACs back with her job, Alice would prefer not to worry about constructing her messages to Bob herself, so she employs Charlie to handle their assembly for her. Charlie is skilled in the art of passing messages to Alice, but feels that actually constructing messages is outside of his responsibilities. With her agreement, Charlie decides to construct a message factory in Alice’s shed (which she affectionately named David). Thanks to Alice’s lucrative career, David is a rather magnificent expanding shed which will always have space to store more, with a hard upper limit defined by the size of Alice’s garden. Now, David the message factory is only really responsible for fulfilling requests for messages, so Charlie fills it with workers: Eve::Hello and Eve::SendMe100Pounds who will be responsible for constructing the messages themselves. Sadly, nothing is ever simple in the world of message writing; no two messages are ever the same and as such each requires a slightly different set of tools be available for its construction. Since the Eves would prefer to focus only on constructing messages, not collecting tools, each Eve is assigned an assistant Frank::Hello, Frank::SendMe100Pounds and so on. Of course, the Franks can’t be allowed to degrade the smooth running of the message factory whilst they gather tools for their respective Eves, so Alice purchases an additional magic shed to house the Franks: Gertrude, to be placed adjacent to David.
The message construction workflow is now perfect, but Alice still has concerns about security. She would like for her messages to be encrypted. Unfortunately, the Eves are not particularly knowledgeable when it comes to encrypting messages (though they may know a thing or two about decrypting them). Thankfully Alice is still in contact with her old colleague, Harriet, whom she asks to handle encryption of messages for her. Harriet agrees; she’s given a small work area near Gertrude and will encrypt any messages passed to her by the Eves so long as the messages are constructed according to a uniform interface which she can understand.
Finally Alice is able to send messages to Bob (or, at least, she is able have them constructed then send them with the help of her friends Ingrid, James, Katherine, Laura, Morgan::SimpleMessage, Morgan::MultiPacketMessage, Nathan and Oliver). Unfortunately she finds that, as the range of messages she wishes to send to Bob grows, so too must David and Gertrude – in order to house their Eves and Franks respectively. Alice’s garden quickly runs out of space for magical growing sheds and Alice is forced to come to an agreement with her neighbour to use their garden as extra shed space. Of course, the story doesn’t end here; David and Gertrude are sufficiently magical that they can grow infinitely so long as there is space to grow into. However, since they have been placed back to back, finding space for growth isn’t necessarily trivial. Each time one of them wants to grow they must move their entire contents to a new part of the garden first. Each time this happens, small collections of tools, temporary message storage cupboards – and, from time to time, factory workers who were accidentally erased from records and thus cannot be moved – are left behind. This miscellany of items left behind each time a factory grows means that previously-occupied regions of Alice’s garden are next to useless – ultimately, her additional garden space hasn’t increased her ability to produce a variety of messages all that much.
Resigning herself to a small set of trivial messages to send to Bob, Alice goes about utilising her message production line. What she finds is that, unfortunately, the throughput is far lower than she had expected. What she notices is that each time an Eve needs to encrypt a message, she has such a long walk to Harriet’s quarters that by the time she gets back to her own station within David she’s forgotten how to construct messages. Similarly, when they access the tools and message storage cupboards littered around the garden they experience the same effect. At first the Eves only need to quickly read the instructional text printed on their message construction equipment to re-acquaint themselves with the art of message construction. However, as the factories grow further and further away from Harriet’s desk the Eves are forced to look up parts of the process in large reference books and sometimes even require complete re-training.
Alice is furious. After months of effort she’s spent huge amounts of money developing a process which costs more per message produced than she hoped and doesn’t produce nearly as many messages as she had predicted or as fast as she’d have liked.
Alice asks Harriet if she can just encrypt some dictated messages. Harriet never wants to speak to Alice again. Alice is in debt to everyone within a three mile radius of her house. Bob has passed away.
Poor Bob