announcements: 1. today: digital cash 2. tomorrow: quiz on ch. 6-9 1.8 questions 3. thursday:...
Post on 20-Dec-2015
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Announcements:Announcements:1.1. Today: digital cashToday: digital cash
2.2. Tomorrow: quiz on ch. 6-9Tomorrow: quiz on ch. 6-91.1. 8 questions8 questions
3.3. Thursday: presentationsThursday: presentationsElliptic curvesElliptic curves
MD5 vulnerabilitiesMD5 vulnerabilities
4.4. Friday: workday for presentations. Friday: workday for presentations. 1.1. Anyone needing help can meet me in my office.Anyone needing help can meet me in my office.
Questions? Questions?
DTTF/NB479: DszquphsbqizDTTF/NB479: Dszquphsbqiz Day 33Day 33
One last (set of) Schneier joke(s)One last (set of) Schneier joke(s)
http://geekz.co.uk/schneierfacts/ http://geekz.co.uk/schneierfacts/
Digital Cash: goalsDigital Cash: goals
Electronic: want speed and securityElectronic: want speed and security
Can’t be counterfeitedCan’t be counterfeited
Anonymous: spender’s ID not disclosed to Anonymous: spender’s ID not disclosed to merchantmerchant
Payment done offlinePayment done offline
TransferableTransferable
Divisible (can make change)Divisible (can make change)
Okimoto and Ohta: Universal electronic cash, In Proc. Advances in Computing – CRYPTO, 1991
Digital Cash ExerciseDigital Cash Exercise
T&W 11.1 summarizes a system satisfying goals 1-4 T&W 11.1 summarizes a system satisfying goals 1-4 (can’t give coins away, a single denomination only)(can’t give coins away, a single denomination only)
Focus is on preventing fraud due to double-spendingFocus is on preventing fraud due to double-spending Adds lots of complexityAdds lots of complexity Interpret this as “adds lots of equations”Interpret this as “adds lots of equations”
Handout Handout Read/skim the 3-page summary of chapter.Read/skim the 3-page summary of chapter. Do the questions alone or with a partner.Do the questions alone or with a partner.