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Old Version 34

changes.mady.by.user Kenneth R Schumacher

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New Version 35

changes.mady.by.user Unknown User (steb@mit.edu)

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Key

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Safety: There are two potential safety problems: the user could be tricked into adding the wrong contact or fail to enter they key correctly. Dealing with the former is beyond the scope of this application and the latter can be dealt with by including error detection in the key.

To shareallow Stephan to contact them, each member of Team Morris clicks the Actions button next to Stephan's name in their contacts page. They are then presented with the following dialog from which they select Send Contact Information.

Learnability: Learning that one can send contact information to a user by clicking on Actions is not obvious and will probably have to be taught by another user. However, putting a button on the contact itself would clutter the interface and confuse the user further.

Efficiency: This method of sharing contact information is very efficient and requires very little work on the coordinator's part.

Safety: This method of sharing contact information could lead a user to accidentally tell the wrong person who they are. However, contacts are generally assumed to be mutual so this shouldn't be a problem.
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As Stephan created this identity for this event, he knows that it is only known to members of Team Morris. As such, Stephan trusts any new contact information at face value. Stephan receives these requests as messages.
Learnability: As it uses the messaging system, there is nothing new to learn.
Efficiency: Adding multiple contacts could be slow.
Safety: The user could easily be tricked into adding an untrusted contact. Time sensitive codes could be used to mitigate this.

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Later that day, when Stephan learns that the members of Team Morris should move back to the city, he sends a message to Mark Dunn by browsing to the contacts page, clicking Actions next to his name, and clicking Send Message.
Learnability: This is fairly standard and straight forward.
Efficiency: Sending a message to multiple contacts is inefficient.
Safety: Explicitly choosing the recipient reduces the risk of sending to the wrong person.

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Stephan is then presented with a send message dialog.
Learnability: Like email.
Efficiency: Typing speed.
Safety: Including the recipient in the send button further reduces the changes of sending to the wrong person.
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Mark receives the message as the following.

Design 2

Adding/Managing Contacts

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Storyboard

Learnability

Efficiency

Safety



Secure Chat Window

Stephen must now update the team with new orders. On the Messaging tab,
Stephen can see a conversation with an individual or group, much like the
standard chat application on his phone. In this case, his can message John Doe
securely because he has a public key stored for him. The application reminds him
that he can securely communicate via color (background color), and each past
message that was sent with encryption is also set off by color and a lock icon. Groups
can be handled similarly to individuals with a group key.

Touching on the message area to enter a message brings up the keyboard and a lock
button, giving access to encryption options for the message (encrypt via personal
private key or public key of John Doe). The default encrypts via public key to ensure
safety, but Stephen can remove this if he decides encryption is not necessary for a particular message.

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||\Unsecure Chat Window

This is the same view of the messaging window but for a contact without a stored
public key. The background color is red, reminding Stephen that no message can
be sent securely, and the lock icon near the message window is disabled.

Pros:  Mimics Conversation/Chat flow concepts.
Multiple signals for secure or unsecure communications
(lock icon near name, Lock on each securely sent/received
message, background color, message bubble color).

Cons: User must learn difference between using public or
private key. 

Pros:  Streamlined interface for all secure and
unsecure communications with a single person or
group.

Default option uses secure public key encryption,
which requires user intervention if a different option
is desired (assumes this is the most likely selected
option).

Cons: Receiving a secure message
requires decryption using either personal private
or contact's public key, requiring extra time.

Pros:  Multiple visual cues to signify message security.

Cons: User can still send an unsecure message, so there
is still risk of secret information being sent unsecurely.

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