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A Natural Language Approach to Automated Cryptanalysis of Two-time Pads Joshua Mason Kathryn Watkins Jason Eisner Adam Stubblefield The Two Time Pad Problem Attack at Dawn doQvYcSWIPyXaC Attack at Dawn doQvYcSWIPyXaC Take the

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SLIDE 1

A Natural Language Approach to Automated Cryptanalysis of Two-time Pads

Joshua Mason Kathryn Watkins Jason Eisner Adam Stubblefield

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SLIDE 2

The Two Time Pad Problem

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SLIDE 3

⊕ Attack at Dawn doQvYcSWIPyXaC

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SLIDE 4

Take the Beach ⊕ doQvYcSWIPyXaC ⊕ Attack at Dawn doQvYcSWIPyXaC

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SLIDE 5

⊕ Take the Beach ⊕ doQvYcSWIPyXaC ⊕ Attack at Dawn doQvYcSWIPyXaC

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SLIDE 6

⊕ Take the Beach Attack at Dawn ⊕ doQvYcSWIPyXaC doQvYcSWIPyXaC ⊕

⊕

Take the Beach ⊕ doQvYcSWIPyXaC ⊕ Attack at Dawn doQvYcSWIPyXaC

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SLIDE 7

⊕ Take the Beach Attack at Dawn ⊕ doQvYcSWIPyXaC doQvYcSWIPyXaC ⊕

⊕

Take the Beach ⊕ doQvYcSWIPyXaC ⊕ Attack at Dawn doQvYcSWIPyXaC

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SLIDE 8

⊕ Take the Beach Attack at Dawn ⊕ Take the Beach ⊕ doQvYcSWIPyXaC ⊕ Attack at Dawn doQvYcSWIPyXaC

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SLIDE 9

Take the Beach Attack at Dawn ⊕

15 15 1f 04 43 1f 48 04 54 62 21 00 14 6

=

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SLIDE 10
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SLIDE 11
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SLIDE 12
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SLIDE 13
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SLIDE 14

OJNcDfoMncXzYwwQQZRXYWORT190LP

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SLIDE 15

OJNcDfoMncXzYwwQQZRXYWORT190LP the ⊕

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SLIDE 16

QpL OJNcDfoMncXzYwwQQZRXYWORT190LP the ⊕

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SLIDE 17

OJNcDfoMncXzYwwQQZRXYWORT190LP the ⊕

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SLIDE 18

the ⊕ Man OJNcDfoMncXzYwwQQZRXYWORT190LP

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SLIDE 19

Formalized by F. Rubin in 1978 Automated by E. Dawson and L. Nielson in 1996

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SLIDE 20

Assumptions

  • Uppercase English characters and space
  • Space is always the most frequent character
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SLIDE 21

P0 ⊕ P1 = 6e 71 00 6f 79 61

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SLIDE 22

P0 ⊕ P1 = 6e 71 00 6f 79 61

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SLIDE 23

P0 ⊕ P1 = 6e 71 6f 79 61

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SLIDE 24

P0 ⊕ P1 = 6e 71 6f 79 61

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SLIDE 25

P1 ⊕ P2 = 67 82 00 00 00 00 00 34

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SLIDE 26

P1 ⊕ P2 = 67 82 00 00 00 00 00 34

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SLIDE 27

P1 ⊕ P2 = 67 82 00 00 00 34

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SLIDE 28

Testing Methodology

  • Trained on the first 600K characters of the

Bible

  • Attempted recovery of passages from first

600K characters of the bible

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SLIDE 29

P0 ⊕ P1

62.7%

P1 ⊕ P2

61.5%

P0 ⊕ P1

62.6%

Percentage Correctly Recovered Dawson & Nielson

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SLIDE 30

P0 ⊕ P1

62.7% 100%

P1 ⊕ P2

61.5% 99.99%

P0 ⊕ P1

62.6% 99.96%

Percentage Correctly Recovered Dawson & Nielson Our Technique

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SLIDE 31

Our Assumptions

  • Plaintext has some structure
  • Plaintext is in a language we know
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SLIDE 32

n-gram count

2 a 2 p 2 l 1 e 2

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SLIDE 33
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SLIDE 34

7 billion characters

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SLIDE 35

450 million characters 7 billion characters

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SLIDE 36

4 billion characters 450 million characters 7 billion characters

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SLIDE 37

apple

  • range
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SLIDE 38

start a

  • P0 ⊕ P1

0e 02 11 02

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SLIDE 39

start a

  • p(a) p(o)

P0 ⊕ P1

0e 02 11 02

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SLIDE 40

start a

  • a

p(a) p(o) p(o) p(a)

P0 ⊕ P1

0e 02 11 02

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SLIDE 41

start a

  • a

ap

  • r
  • r

ap p(p|a) p(r|o) p(r|o) p(p|a) p(a) p(o) p(o) p(a)

P0 ⊕ P1

0e 02 11 02

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SLIDE 42

start a

  • a

ap

  • r
  • r

ap app

  • ra
  • ra

app p(a) p(o) p(o) p(a) p(p|a) p(r|o) p(r|o) p(p|a) p(p|ap) p(a|or) p(a|or) p(p|ap)

P0 ⊕ P1

0e 02 11 02

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SLIDE 43

start a

  • a

ap

  • r
  • r

ap p(p|a) p(r|o) p(r|o) p(p|a) p(a) p(o) p(o) p(a)

P0 ⊕ P1

0e 02 0e 02

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SLIDE 44

start a

  • a

ap

  • r
  • r

ap apa

  • ro
  • ro

apa p(p|a) p(r|o) p(r|o) p(p|a) p(a) p(o) p(o) p(a) p(a|ap) p(o|or) p(o|or) p(a|ap)

P0 ⊕ P1

0e 02 0e 02

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SLIDE 45

start a

  • a

ap

  • r
  • r

ap apa

  • ro
  • ro

apa p(a|ap) p(o|or) p(o|or) p(a|ap) p(p|a) p(r|o) p(r|o) p(p|a) p(a) p(o) p(o) p(a)

P0 ⊕ P1

0e 02 0e 02

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SLIDE 46

Memory/Computation

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SLIDE 47

start a b c

P2 ⊕ P3 01 00 02 02

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SLIDE 48

start b c c

P2 ⊕ P3 01 00 02 02

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SLIDE 49

start b c c b

P2 ⊕ P3 01 00 02 02

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SLIDE 50

start b c c b ba ca bb cb bc cc ca ba cb bb cc bc

P2 ⊕ P3 01 00 02 02

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SLIDE 51

start b c c b p(b) p(c) p(c) p(b)

P2 ⊕ P3 01 00 02 02

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SLIDE 52

b c c b p(b) p(c) p(c) p(b)

P2 ⊕ P3 01 00 02 02

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SLIDE 53

p(b) p(c) p(c) p(b) ba ca bb cb bc cc ca ba cb bb cc bc b c c b

P2 ⊕ P3 01 00 02 02

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SLIDE 54

p(b) p(c) p(c) p(b) ba ca bb cb bc cc ca ba cb bb cc bc b c c b p(a|b) p(a|c) p(b|b) p(b|c) p(c|b) p(c|c) p(a|c) p(a|b) p(b|c) p(b|b) p(c|c) p(c|b)

P2 ⊕ P3 01 00 02 02

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SLIDE 55

ba ca bb cb bc cc ca ba cb bb cc bc p(a|b) p(a|c) p(b|b) p(b|c) p(c|b) p(c|c) p(a|c) p(a|b) p(b|c) p(b|b) p(c|c) p(c|b)

P2 ⊕ P3 01 00 02 02

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SLIDE 56

ba ca bb cb bc cc ca ba cb bb cc bc

P2 ⊕ P3 01 00 02 02

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SLIDE 57

ba ca ca ba cc bc

P2 ⊕ P3 01 00 02 02

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SLIDE 58

ba ca ca ba cc bc

... P2 ⊕ P3 01 00 02 02

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SLIDE 59

... P2 ⊕ P3 01 00 02 02

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SLIDE 60

... END P2 ⊕ P3 01 00 02 02

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SLIDE 61

END P2 ⊕ P3 01 00 02 02

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SLIDE 62

ba ca

... END

b c

P2 ⊕ P3 01 00 02 02

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SLIDE 63

Commodity Hardware

System

Dual Core Pentium 3 GHz

Memory

8 GB

Storage

1.2 TB

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SLIDE 64

Model Build Time

~12 hours

Runtime

200 ms per byte

Memory Usage

~2 GB

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SLIDE 65

Our testing methodology

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SLIDE 66

402,590 Files 98,699 Files 520,931 Files

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SLIDE 67

402,590 Files 98,699 Files 520,931 Files 2,590 Files 8,699 Files 20,931 Files

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SLIDE 68

402,590 Files 98,699 Files 520,931 Files 2,590 Files 8,699 Files 20,931 Files 50 Files 50 Files 50 Files

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SLIDE 69

Small HTML

90.64%

E-mail

82.29%

Documents

53.84%

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SLIDE 70

Small Medium HTML

90.64% 92.78%

E-mail

82.29% 89.04%

Documents

53.84% 53.05%

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SLIDE 71

Small Medium Large HTML

90.64% 92.78% 93.79%

E-mail

82.29% 89.04% 90.85%

Documents

53.84% 53.05% 52.72%

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SLIDE 72

The Switching Problem

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SLIDE 73

I want to remind you about

  • ur All-Employee Meeting this

Tuesday, Oct. 23, at 10 a.m. Houston time at the Hyatt

  • Regency. We obviously have a

lot to talk about. Last week Well I hope you have Dad doing some of the cleaning! You know how he always has an

  • pinion but yet no
  • participation. Anyway I hope

you're doing fine. I'm fine

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SLIDE 74

I want to remind you about

  • ur All-Employee Meeting this

Tuesday, Oct. 23, at 10 a.m. Houston time at the Hyatt Regency participation. Anyway I hope you're doing

  • fine. I'm fine and about to

Well I hope you have Dad doing some of the cleaning! You know how he always has an

  • pinion but yet no. We
  • bviously have a lot to talk
  • about. Last week we reported

third quarter earnings. We

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SLIDE 75

Wu showed Word 2002 re-uses one time pad

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SLIDE 76 T 1 3 / 1 5 1 D r e v i s i
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1

Working T13 Draft 1510D

R e v i s i
  • n
1 . J a n u a r y 1 7 , 2 3

A T A / A T A P I H

  • s

t A d a p t e r s S t a n d a r d ( A T A – A d a p t e r )

T h i s i s a n i n t e r n a l w
  • r
k i n g d
  • c
u m e n t
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T 1 3 , a T e c h n i c a l C
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m i t t e e
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A c c r e d i t e d S t a n d a r d s C
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m i t t e e I N C I T S . T h e T 1 3 T e c h n i c a l C
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m i t t e e m a y m
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i f y t h e c
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t e n t s . T h i s d
  • c
u m e n t i s m a d e a v a i l a b l e f
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r e v i e w a n d c
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m e n t
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l y . P e r m i s s i
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i s g r a n t e d t
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e m b e r s
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I N C I T S , i t s t e c h n i c a l c
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m i t t e e s , a n d t h e i r a s s
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i a t e d t a s k g r
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p s t
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e p r
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u c e t h i s d
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u m e n t f
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t h e p u r p
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e s
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I N C I T S s t a n d a r d i z a t i
  • n
a c t i v i t i e s w i t h
  • u
t f u r t h e r p e r m i s s i
  • n
, p r
  • v
i d e d t h i s n
  • t
i c e i s i n c l u d e d . A l l
  • t
h e r r i g h t s a r e r e s e r v e d . A n y c
  • m
m e r c i a l
  • r
f
  • r
  • p
r
  • f
i t r e p l i c a t i
  • n
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r e p u b l i c a t i
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i s p r
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i b i t e d . T 1 3 T e c h n i c a l E d i t
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: T
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y G
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f e l l
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P a c i f i c D i g i t a l C
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p
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a t i
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2 5 2 A l t
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P a r k w a y I r v i n e , C A 9 2 6 2 U S A T e l : 9 4 9
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5 2
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1 1 1 F a x : 9 4 9
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5 2
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3 9 7 E m a i l : t g
  • d
f e l l
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@ p a c i f i c d i g i t a l . c
  • m

W

  • r

k i n g T 1 3 D r a f t 1 5 3 2 D V

  • l

u m e 1

Revision 2 18 February 2003

I n f

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m a t i

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T e c h n

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y

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T A t t a c h m e n t w i t h P a c k e t I n t e r f a c e – 7 V

  • l

u m e 1 ( A T A / A T A P I

  • 7

V 1 )

This is an internal working document of T13, a Technical Committee of Accredited Standards Committee
  • INCITS. As such, this is not a completed standard and has not been approved. The contents may be modified
by the T13 Technical Committee. This document is made available for review and comment only. Permission is granted to members of INCITS, its technical committees, and their associated task groups to reproduce this document for the purposes of INCITS standardization activities without further permission, provided this notice is included. All other rights are reserved. Any commercial or for-profit replication or republication is prohibited. T13 Technical Editor: Peter T. McLean Maxtor Corporation 2190 Miller Drive Longmont, CO 80501-6744 USA Tel: 303-678-2149 Fax: 303-682-4811 Email: pete_mclean@maxtor.com R e f e r e n c e n u m b e r A N S I I N C I T S . * * *
  • x
x x x P r i n t e d O c t
  • b
e r , 1 7 , 2 6 1 2 : 5 6 P M
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SLIDE 77

W

  • r

k i n g T 1 3 D r a f t 1 5 3 2 D V

  • l

u m e 1

Revision 2 18 February 2003

I n f

  • r

m a t i

  • n

T e c h n

  • l
  • g

y

  • A

T A t t a c h m e n t w i t h P a c k e t I n t e r f a c e – 7 V

  • l

u m e 1 ( A T A / A T A P I

  • 7

V 1 )

This is an internal working document of T13, a Technical Committee of Accredited Standards Committee
  • INCITS. As such, this is not a completed standard and has not been approved. The contents may be modified
by the T13 Technical Committee. This document is made available for review and comment only. Permission is granted to members of INCITS, its technical committees, and their associated task groups to reproduce this document for the purposes of INCITS standardization activities without further permission, provided this notice is included. All other rights are reserved. Any commercial or for-profit replication or republication is prohibited. T13 Technical Editor: Peter T. McLean Maxtor Corporation 2190 Miller Drive Longmont, CO 80501-6744 USA Tel: 303-678-2149 Fax: 303-682-4811 Email: pete_mclean@maxtor.com R e f e r e n c e n u m b e r A N S I I N C I T S . * * *
  • x
x x x P r i n t e d O c t
  • b
e r , 1 7 , 2 6 1 2 : 5 6 P M T13/1510D revision 1

Working T13 Draft 1510D

Revision 1.0 January 17, 2003

A T A / A T A P I H

  • s

t A d a p t e r s S t a n d a r d ( A T A – A d a p t e r )

This is an internal working document of T13, a Technical Committee of Accredited Standards Committee
  • INCITS. The T13 Technical Committee may modify the contents. This document is made available for review
and comment only. Permission is granted to members of INCITS, its technical committees, and their associated task groups to reproduce this document for the purposes of INCITS standardization activities without further permission, provided this notice is included. All other rights are reserved. Any commercial or for-profit replication or republication is prohibited. T13 Technical Editor: Tony Goodfellow Pacific Digital Corporation 2052 Alton Parkway Irvine, CA92602 USA Tel: 949-252-1111 Fax: 949-252-9397 Email: tgoodfellow@pacificdigital.com

Revision 1 January 17, 2003

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SLIDE 78 T 1 3 / 1 5 1 D r e v i s i
  • n
1

Working T13 Draft 1510D

R e v i s i
  • n
1 . J a n u a r y 1 7 , 2 3

A T A / A T A P I H

  • s

t A d a p t e r s S t a n d a r d ( A T A – A d a p t e r )

T h i s i s a n i n t e r n a l w
  • r
k i n g d
  • c
u m e n t
  • f
T 1 3 , a T e c h n i c a l C
  • m
m i t t e e
  • f
A c c r e d i t e d S t a n d a r d s C
  • m
m i t t e e I N C I T S . T h e T 1 3 T e c h n i c a l C
  • m
m i t t e e m a y m
  • d
i f y t h e c
  • n
t e n t s . T h i s d
  • c
u m e n t i s m a d e a v a i l a b l e f
  • r
r e v i e w a n d c
  • m
m e n t
  • n
l y . P e r m i s s i
  • n
i s g r a n t e d t
  • m
e m b e r s
  • f
I N C I T S , i t s t e c h n i c a l c
  • m
m i t t e e s , a n d t h e i r a s s
  • c
i a t e d t a s k g r
  • u
p s t
  • r
e p r
  • d
u c e t h i s d
  • c
u m e n t f
  • r
t h e p u r p
  • s
e s
  • f
I N C I T S s t a n d a r d i z a t i
  • n
a c t i v i t i e s w i t h
  • u
t f u r t h e r p e r m i s s i
  • n
, p r
  • v
i d e d t h i s n
  • t
i c e i s i n c l u d e d . A l l
  • t
h e r r i g h t s a r e r e s e r v e d . A n y c
  • m
m e r c i a l
  • r
f
  • r
  • p
r
  • f
i t r e p l i c a t i
  • n
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r e p u b l i c a t i
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i s p r
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i b i t e d . T 1 3 T e c h n i c a l E d i t
  • r
: T
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y G
  • d
f e l l
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P a c i f i c D i g i t a l C
  • r
p
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a t i
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2 5 2 A l t
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P a r k w a y I r v i n e , C A 9 2 6 2 U S A T e l : 9 4 9
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5 2
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1 1 1 F a x : 9 4 9
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5 2
  • 9
3 9 7 E m a i l : t g
  • d
f e l l
  • w
@ p a c i f i c d i g i t a l . c
  • m

Working T13 Draft 1532D Volume 1

R e v i s i
  • n
2 1 8 F e b r u a r y 2 3

I n f

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m a t i

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T e c h n

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y

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T A t t a c h m e n t w i t h P a c k e t I n t e r f a c e – 7 V

  • l

u m e 1 ( A T A / A T A P I

  • 7

V 1 )

T h i s i s a n i n t e r n a l w
  • r
k i n g d
  • c
u m e n t
  • f
T 1 3 , a T e c h n i c a l C
  • m
m i t t e e
  • f
A c c r e d i t e d S t a n d a r d s C
  • m
m i t t e e I N C I T S . A s s u c h , t h i s i s n
  • t
a c
  • m
p l e t e d s t a n d a r d a n d h a s n
  • t
b e e n a p p r
  • v
e d . T h e c
  • n
t e n t s m a y b e m
  • d
i f i e d b y t h e T 1 3 T e c h n i c a l C
  • m
m i t t e e . T h i s d
  • c
u m e n t i s m a d e a v a i l a b l e f
  • r
r e v i e w a n d c
  • m
m e n t
  • n
l y . P e r m i s s i
  • n
i s g r a n t e d t
  • m
e m b e r s
  • f
I N C I T S , i t s t e c h n i c a l c
  • m
m i t t e e s , a n d t h e i r a s s
  • c
i a t e d t a s k g r
  • u
p s t
  • r
e p r
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u c e t h i s d
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u m e n t f
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t h e p u r p
  • s
e s
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I N C I T S s t a n d a r d i z a t i
  • n
a c t i v i t i e s w i t h
  • u
t f u r t h e r p e r m i s s i
  • n
, p r
  • v
i d e d t h i s n
  • t
i c e i s i n c l u d e d . A l l
  • t
h e r r i g h t s a r e r e s e r v e d . A n y c
  • m
m e r c i a l
  • r
f
  • r
  • p
r
  • f
i t r e p l i c a t i
  • n
  • r
r e p u b l i c a t i
  • n
i s p r
  • h
i b i t e d . T 1 3 T e c h n i c a l E d i t
  • r
: P e t e r T . M c L e a n M a x t
  • r
C
  • r
p
  • r
a t i
  • n
2 1 9 M i l l e r D r i v e L
  • n
g m
  • n
t , C O 8 5 1
  • 6
7 4 4 U S A T e l : 3 3
  • 6
7 8
  • 2
1 4 9 F a x : 3 3
  • 6
8 2
  • 4
8 1 1 E m a i l : p e t e _ m c l e a n @ m a x t
  • r
. c
  • m
R e f e r e n c e n u m b e r A N S I I N C I T S . * * *
  • x
x x x P r i n t e d O c t
  • b
e r , 1 7 , 2 6 1 2 : 5 6 P M

Revision 2 18 February 2003

slide-79
SLIDE 79
  • November 13, 2002 ATA/ATAPI Host

Adapters Standard (ATA Adapter) This is an internal working document

  • f T13, a Technical Committee of

Accredited Standards Committee

  • INCITS. The T13 Technical Committee

may modify the contents. This document is made available for review and comment only. Permission is granted to members of INCITS, its technical committees, and their associated task groups to reproduce

slide-80
SLIDE 80
  • November 13, 2002 ATA/ATAPI Host

Adapters Standard (ATF; h Packet) This is no internal working document

  • f T13, a Technical Committee of

Accredited Standards Committee

  • INCITS. The T13 Technical Committee

may modify the contents. This document is made available and has not been approved. The contents may be modified by the T13 Technical technical committees, and their associated task groups to reproduce

slide-81
SLIDE 81
  • November 13, 2002 ATA/ATAPI Host

Adapters Standard (ATF; h Packet) This is no internal working document

  • f T13, a Technical Committee of

Accredited Standards Committee

  • INCITS. The T13 Technical Committee

may modify the contents. This document is made available and has not been approved. The contents may be modified by the T13 Technical technical committees, and their associated task groups to reproduce

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SLIDE 82

Exact Pairwise HTML

93.79% 99.45%

E-mail

90.85% 98.41%

Documents

52.72% 75.91%

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SLIDE 83

Take the Beach ⊕ doQvYcSWIPyXaC ⊕ Attack at Dawn doQvYcSWIPyXaC

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SLIDE 84

Take the Beach ⊕ doQvYcSWIPyXaC ⊕ Attack at Dawn doQvYcSWIPyXaC Bring me Cakes ⊕ doQvYcSWIPyXaC

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SLIDE 85

Take the Beach ⊕ doQvYcSWIPyXaC ⊕ Attack at Dawn doQvYcSWIPyXaC ⊕ Take the Beach Attack at Dawn ⊕

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SLIDE 86

⊕ Attack at Dawn doQvYcSWIPyXaC ⊕ Attack at Dawn ⊕ Bring me Cakes Bring me Cakes ⊕ doQvYcSWIPyXaC

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SLIDE 87

Take the Beach ⊕ doQvYcSWIPyXaC ⊕ Take the Beach ⊕ Bring me Cakes Bring me Cakes ⊕ doQvYcSWIPyXaC

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SLIDE 88

⊕ ⊕ ⊕ Attack at Dawn Take the Beach Take the Beach Attack at Dawn Bring me Cakes Bring me Cakes

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SLIDE 89

⊕ Attack at Dawn Take the Beach

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SLIDE 90

⊕ Attack at Dawn Take the Beach A T

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SLIDE 91

⊕ Take the Beach Bring me Cakes ⊕ Attack at Dawn Take the Beach A T T B

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SLIDE 92

Small HTML

99.96%

E-mail

98.24%

Documents

69.92%

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SLIDE 93

Small Medium HTML

99.96% 99.95%

E-mail

98.24% 98.33%

Documents

69.92% 71.11%

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SLIDE 94

Small Medium Large HTML

99.96% 99.95% 99.95%

E-mail

98.24% 98.33% 98.34%

Documents

69.92% 71.11% 69.39%

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SLIDE 95

⊕

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SLIDE 96

Large HTML

93.79%

E-mail ⊕ HTML

96.60%

E-mail

90.85%

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SLIDE 97

Able to recover plaintext with over 99% accuracy

Conclusions

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SLIDE 98

Able to recover plaintext with over 99% accuracy Technique works on different document types

Conclusions

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SLIDE 99

Able to recover plaintext with over 99% accuracy Technique works on different document types Keystream reuse is a real problem

Conclusions