Chapter 4: Identity and Anonymity Flashcards
What is the strongest form of identity?
Identified individual
What is a form of identity that is weaker than identified individual?
Pseudonymous
What can be done with a pseudonym?
Link different data items about the same individual without knowing the actual person the data is about
What is the weakest form of identity?
Anonymity
Describe truly anonymous data
We not only do not know the individual the data is about, we cannot even tell if two data items are about the same individual
Why are roles important in privacy?
Often, it is not important who an individual is, only that the person is authorized to perform an action
Provide an example of how a role can be used to reduce the need to identify an individual?
A credit card account may have several authorized users, and the merchant only needs to know that one of the authorized users is making a purchase (a role), not which one (an identity)
How can an individual increase their level of privacy when sending an email or when accessing services on the web?
Use a hash function to prove their identity without revealing it
Use a 3rd party to validate their identity
Why would a system need to know a person’s identity?
- Access control
- Attribution - the ability to prove who performed an action
- Enhanced user experience and personalization
How can you increase privacy but still personalize a website to each user?
Use a pseudonym
What do you need to represent identity?
- A combination of information that is unique (name + DoB) - this typically results in an identified individual
- User-specified identifier (user ID)
- System-generated user IDs
- Externally created unique IDs (for example an email)
- Identity systems (google wallet, PKI)
- Biometrics
What are the advantages of using user IDs?
- The system can guarantee uniqueness
* Provides pseudonymity
What are the disadvantages of using user-specified user IDs?
- Users may want the same user ID
- Users who forget their user ID may try something generic like their last name and end up locking someone else out of their account after multiple tries
What are the advantages of system-generated user IDs over user-specified user IDs?
• Provides greater privacy - a user-specified ID may include personal information like their name
What are the advantages of using an externally created unique IDs?
- User friendly (user can reuse another identifier)
- Reduces the number of identifiers a user needs to remember
- The burden of providing uniqueness is outsourced
- Information can be linked across systems
- Easier to detect fraud or identity theft
What are the dangers of using some biometrics as an identifier?
- Face recognition is not accurate enough in large groups of people - you might end up with false positives
- Using it for both identification and authentication could provide someone with inappropriate access
What is the purpose of authentication?
Used to ensure that an individual performing an action matches the expected identity
What are the 4 main categories of authentication mechanisms?
- What you know - passwords or personal information
- What you have - requiring an object
- Where you are - location
- What you are - biometrics
What needs to be considered when deciding which authentication mechanism to use?
Challenges of creating and revoking the chosen credentials
What is the advantage of using passwords?
High level of assurance that the correct individual is being identified
What is the disadvantage of using passwords?
They can be easily broken
List the 2 categories of password-based authentication attacks
- Attacks on the password itself
* Attacks performed directly through the system
How can you avoid password guessing attacks and how could it negatively affect users?
Apply a limit on failed password attempts - places a burden on legitimate users who incorrectly enter their password
Provide an example of a password guessing attack method
Dictionary attack
Provide two examples of password-based attacks performed directly through the system?
- Man-in-the-middle attack
* Replay attack
How can man-in-the-middle attacks be combated?
Encrypting the password
How do replay attacks work?
- Usually combined with man-in-the-middle attack when the password is encrypted
- The hashed password is replayed to gain access
How can you combat a replay attack?
Issue a unique challenge for each authentication
For example, using a different encryption key for each authentication attempt