ACM International Collegiate Programming Contest

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ACM International Collegiate Programming Contest
Banff Springs, Alberta April 6 10, 2008
Sep. 22 (local) Oct. 6 (Oswego
preliminary) Nov. 10 (RIT regional final)
stefanko_at_cs.rochester.edu Sep. 11, CBS 601,
415pm
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(No Transcript)
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Office hours
Instructor office hours (CSB 620) Monday
12noon-1pm Thursday - after class TA office
hours (CSB 728) Monday 4pm - 5pm
Wednesday 4pm - 5pm
Problem sessions
Friday 8am 9am, CSB 601
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Homework 1
1) you should receive email saying which parts
do you need to solve (A,C,I) 2) if you do not
receive the email by today evening send
me email 3) has to be typeset on a computer,
turn in 2 copies by
Sep. 20
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Quiz 1 Number Theory and Cryptography
Sep 6 Sep 11 Sep 13 Sep 18
pages 1-44
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Cryptography
BOB
ALICE
EVE
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Cryptography private key
Ksecret key
Ksecret key
BOB
ALICE
yencode(x,K)
xdecode(y,K)
EVE
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Cryptography public key
A public key B private key
BOB
ALICE
yENCODE(x,A)
xDECODE(y,B)
EVE
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Cryptography public key - RSA
1. pick two large primes p,q, let Npq 2. pick e
such that gcd(e,p-1)1, gcd(e,q-1)1 3. find d
such that e.d ? 1 mod
(p-1)(q-1) 4. announce e,N, keep p,q,d secret
ENCODE(x) xe mod N DECODE(y) yd mod N