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

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Later that day, Stephen receives a message from someone claiming to be on Team Pullman. He asks to establish a secure messaging connection with Stephen, which Stephen agrees to. The other person turns out to be Tom Duffy, campaign manager of Team Pullman, and he suspiciously suggests that Stephen ought to consider working for Team Pullman instead of Team Morris. Stephen does not like where the conversation is heading, and decides to end the conversation. He also erases any record of the conversation occurring and removes Tom as a contact, to ensure that no trace of the conversation can be found.

Design 1

Task #1

First, in order to establish a secure connection, Stephan meets with Team Morris and shares his identity. He does this by going to his Contacts panel and clicking share.

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Learnability: Most potential users will be familiar with QR codes so this screen shouldn't pose a learnability problem. As the key looks like a serial number under a bar code, the user should pick this out as a numerical representation of the QR code.

Efficiency: QR codes are extreamely extremely efficient as the user only needs to take a picture of it.

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Each member of team morris goes to his or her contacts panel and clicks Add. When they do so, they are shown the following: Image Removed
They all , click By QR code Codem and are taken to a standard QR code reader. The contact is then added.

Learnability: Again, most users are familiar with QR codes so adding by QR code should be easy. Sadly, many users are also familiar with entering software activation keys and shouldn't have a problem entering the key manually if they need to.

Efficiency: QR Codes are efficient.

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.

Image Added

To share To give Stephan their contact information,

Design 2

Task #1

Storyboard

Learnability

Efficiency

Safety



Key Management

Stephen must add the new teammates to his list of
secure contacts. The SecureConnect application allows him to log
onto the Key Server set up by the campaign to manage public
keys. He finds that two of the new volunteers had public keys
created for them when issued their mobile phones, so he
adds them to his personal contact list, which include their
mobile phone number and public key. One user was not yet present
in the key server, so Stephen had to help generate a new key for
them.

This design is meant to mimic a standard phone text messaging
layout which the user is likely familiar with, then overlaying
the metaphor of user keys necessary to facilitate encrypted
messaging.

Pros:  The look and feel mimics the standard
text messaging application on a typical smartphone.
Concepts of contacts carry over, with additional public
key data added as an additional facet of contact data.


Cons:

Pros:  Key Server enables contacts to be
added without manual text entry on the phone.

Cons: User is required to obtain public key before
secure communication is possible.

Pros:  Multiple graphical cues suggest that a contact
cannot be securely communicated with until a public key
is stored for that user.
Adding via the Key Server automatically grabs public key data.



Cons: User must be continuously reminded of the unsecure
nature of their conversations until they successfully add a key.
Contacts may still be added even without a key, leaving open
the possibility of communicating without encryption.


Contact Management
Once the new contacts were added from the Key Server,
Stephen is able to view them the contacts tab of the app. Each
newly added secure contact with a stored public key is displayed
with a key icon next to their name at all times. Contacts without a
stored key are also present, and can have a public key entered
on the contact editor in order to make them a secure contact.

Public keys can be entered manually via the keyboard, pasted from
the phone's clipboard (the contact could have sent their key via
email or unsecure text, or could have been located via web
browser).

Pros:

Cons:

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Storyboard

Learnability

Efficiency

Safety



Secure Chat Window

Description of Storyboard

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Unsecure Chat Window|confluence/download/attachments/82324422/photo3.jpg?version=1&modificationDate=1331520439531||||||\

Description of Storyboard

Pros:

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