I538 Introduction to Cryptographyhomes.sice.indiana.edu/henry/courses/b504/s17/slides/lec... ·...
Transcript of I538 Introduction to Cryptographyhomes.sice.indiana.edu/henry/courses/b504/s17/slides/lec... ·...
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Ryan Henry
Spring 2017 • Lecture 1
B504 /I538:Introduction toCryptography
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Ryan Henry
Administrivia
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Ryan Henry
Instructor• Instructor: Ryan Henry
•
• Office hours: Fridays @ 10:30 — 11:30(or by appointment)
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http://homes.soic.indiana.edu/henry
LH 330E
- Alas, Ryan is stuck in Washington DC today ; - (
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Ryan Henry
Associate Instructor (AI)
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• Instructor: Swami Ramesh
• Office hours: Fridays @ 13:30 — 14:30(or by appointment)
LH 330A
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Ryan Henry
Required textbook
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Introduction to Modern Cryptography (2nd edition)
Jonathan Katz and Yehuda LindellChapman & Hall/CRC Cryptography and
Network Security SeriesNovember 2014
Katz’ website IU Bookstore CRC Press Amazon* * *
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Ryan Henry
Course website
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http://homes.soic.indiana.edu/henry/courses/b609/s17
The course website is the official source for:– assignments,– lecture slides,– important announcements,– supplemental material,– etc.
PLEASE CHECK THE COURSE WEBSITE FREQUENTLY!Also, Canvas: https://iu.instructure.com/courses/1600125
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Ryan Henry
Lectures
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Tuesdays and Thursdays
@ 13:00—14:15in Ballantine Hall (BH) 322
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Ryan Henry7
Should I interrupt withquestions during lectures?
A: Only if you want answers(in other words: YES, PLEASE DO!)
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Ryan Henry
Grading and assessment
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8 assignments at 10% each
4 quizzes at 5% each
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Ryan Henry
Grading and assessment
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A+97% B+87% C+77% D+67%
A 93% B 83% C 73% D 63%
A- 90% B- 80% C- 70% D- 60%
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Ryan Henry
Homework
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• One assignment assigned every second Tuesday*
– Due before Tuesday lecture two weeks later
• Mostly written with some coding problems
– ASK FOR HELP EARLY!• We will stop providing help starting 10 days after assignment is distributed!
* with a few exceptions ― see the calendar
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Ryan Henry
Homework (sample timeline)
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Sun Mon Tue Wed Thu Fri Sat
Sun Mon Tue Wed Thu Fri Sat
week N:
week N+1:
Sun Mon Tue Wed Thu Fri Satweek N+2:
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Ryan Henry
Typesetting with
• Written portion of assignments must be typeset using
• We will give you the source for every assignment
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Q: By a show of hands, who here knows ?- If your hand is not up, good news: you get to learn !!
• SoIC has a site license for ShareLaTeX
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Ryan Henry13
When do we starttalking aboutcartography?
A: Umm … Never!(this class is about cryptography!)
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Ryan Henry13
Huh!? No maps??Well what in the @#%★‽! is
“cryptography”?
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Ryan Henry
What in the @#%★‽! isCryptography?And, more generally, what is this course all about?
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Ryan Henry
What is this class all about?• Short answer:The theoretical foundations of modern cryptography
• Cryptography ⊆ mathematics– No specific background is assumed, but
“mathematical maturity” will help– We will cover the necessary math as we go!
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Ryan Henry
What is this class all about?
15 https://xkcd.com/435/On the other hand, physicists like to say that physics is to math as sex is to masturbation
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Ryan Henry
What is this class all about?• Cartography, for starters• But also:
– particulars of deployed encryption schemes– specific “hard” problems– how to implement, use, or break specific
cryptographic software
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ADVICE: Don’t try to implement crypto yourself!
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Ryan Henry
I will make you write lots of proofs
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statement 1statement 2statement 3
⋮statement n
I don’t see whystatement 2
follows fromstatement 1NO MARKS FOR YOU!Peggy
(the prover)
Victor(the verifier)
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Ryan Henry
I will make you write lots of proofs
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Victor is very thorough yet very lazy- will catch every mistake you make…but- cannot be bothered to supply missing details
A perfectly valid complaint for Victor:
“I don’t understand!”(or even, “This is poorly written”) Victor
(the verifier)
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Ryan Henry18
So it’s allmath and proofs?
(See ya—I’m dropping!)
NO!! WAIT!It’s not just any math andproofs…it’s super important,super cool math and proofs!
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Ryan Henry
“Core” crypto• Key establishment
• Secure communication
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m1
confidentiality/integrity
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Ryan Henry
More advanced crypto• Digital signatures
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Ryan Henry
More advanced crypto• Digital signatures• Anonymous communications
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Ryan Henry
More advanced crypto• Digital signatures• Anonymous communications• Oblivious computation
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Ryan Henry
More advanced crypto• Digital signatures• Anonymous communications• Oblivious computation
• Anonymous digital currencies
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Ƀ
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Ryan Henry
Cryptographic protocols• End-to-end verifiable elections
(as if anybody ever suspected an election was rigged!)
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Ryan Henry
Cryptographic protocols• End-to-end verifiable elections
(as if anybody ever suspected an election was rigged!)
• Secure multiparty computation
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f(x1,x2,x3,x4,x5)x1 x3 x5
x2 x4
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Ryan Henry
Crypto magic
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Zero-knowledge proofs
And a whole lot more…
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Ryan Henry
Modern cryptograpy == Science
• Three steps in modern crypto
1. propose a precise threat model2. propose a construction3. prove that breaking construction is “equivalent”
to solving an intractable problem (or impossible)
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Ryan Henry
That’s all for today, folks!
Thursday’s lecture: Discrete probability 101