C S P , C a s p e r a n d S e c u r i t y V e - - PowerPoint PPT Presentation

SLIDE 1

고려대학교 정형기법 연구실

C S P , C a s p e r a n d S e c u r i t y V e r i f i c a t i

• n

김 일 곤 2 3 . 8 . 2

SLIDE 2

S e c u r i t y

S

e c u r i t y : C

• n

f i d e n t i a l i t y , A u t h e n t i c a t i

• n

, I n t e g r i t y a n d A v a i l a b i l i t y

R

e s e a r c h 1 . S e c u r i t y S y s t e m

A c c e s s C

• n

t r

• l

M

• d

e l , I n f

• r

ma t i

• n

F l

• w

M

• d

e l

2

. S e c u r i t y P r

• t
• c
• l

S S H , K e r b e r

• s

, R A D I U S a n d e t c

SLIDE 3

F

• r

ma l A p p r

• a

c h

T

h e

• r

e m P r

• v

i n g

• B

A N , G N Y , S V O l

• g

i c

M

• d

e l C h e c k i n g

• F

D R ( C S P ) , S P I N , S M V , C A D P

T

y p e T h e

• r

y

• P

C C ( P r

• f

C a r r y i n g C

• d

e )

G

l

• b

a l C

• mp

u t i n g

• s

p i c a l c u l u s

SLIDE 4

P r

• c

e s s A l g e b r a a n d C S P

P

r

• c

e s s A l g e b r a

a

f

• r

ma l d e s c r i p t i

• n

t e c h n i q u e t

• c
• mp

l e x c

• mp

u t e r s y s t e ms , e s p e c i a l l y t h

• s

e i n v

• l

v i n g c

• mmu

n i c a t i

• n

, c

• n

c u r r e n t l y e x e c u t i n g c

• mp
• n

e n t s

C

S P ( C

• mmu

n i c a t i n g S e q u e n t i a l P r

• c

e s s e s )

I

t i s a p r

• c

e s s s p e c i f i c a t i

• n

l a n g u a g e d e s i g n e d b y C . A . R . H

• a

r e , a t t h e U n i v e r s i t y

• f

O x f

• r

d d u r i n g t h e 1 9 8 s

A

f

• r

ma l n

• t

a t i

• n

i n w h i c h t h e c

• mp

u t a t i

• n

s

• f

c

• n

c u r r e n t p r

• c

e s s e s c

• mmu

n i c a t i n g b y c h a n n e l c a n b e c

• n

c i s e l y d e s c r i b e d a n d mo d e l l e d .

SLIDE 5

C a s p e r

• C

a s p e r ( A C

• mp

i l e r f

• r

t h e A n a l y s i s

• f

S e c u r i t y P r

• t
• c
• l

s )

• C

S P d e s c r i p t i

• n
• f

t h e s y s t e m i s

1 . v

e r y t i me

• c
• n

s u mi n g

2 . o

n l y p

• s

s i b l e f

• r

p e

• p

l e w e l l p r a c t i c e d i n C S P

2 . e

v e n t h e e x p e r t s w i l l

• f

t e n ma k e mi s t a k e s t h a t p r

• v

e h a r d t

• s

p

• t

※ C a s p e r s i mp l i f i e s t h i s p r

• c

e s s .

SLIDE 6

C a s p e r a n d C S P / F D R

Casper

CSP Modeling

FDR Verification

S e c u r i t y P r

• t
• c
• l

S p e c

• f

S e c u r i t y P r

• t
• c
• l

S p e c

• f

I n t r u d e r

I n t r u d e r

SLIDE 7

C S P Mo d e l i n g

Intiator Responder Server Intruder

take.Alice.y fake.x.Bob send receive learn say receive receive send send

Initiator | | | Responder | | | Server | | | Intruder

leak

SLIDE 8

R e f i n e me n t C h e c k i n g

1

. T r a c e R e f i n e me n t : S a f e t y

2

. F a i l u r e s R e f i n e me n t : D e a d l

• c

k

3

. F a i l u r e s

• D

i v e r g e n c e s R e f i n e me n t : L i v e n e s s

SLIDE 9

R e f i n e me n t C h e c k i n g

Specification Implementation trace (Implementation) trace (Specification) refinement

SLIDE 10

T r a c e s

• f

a P r

• c

e s s

A

t r a c e

• f

a p r

• c

e s s i s a f i n i t e s e q u e n c e

• f

e v e n t s , r e p r e s e n t i n g t h e b e h a v i

• u

r

• f

t h e p r

• c

e s s u p t

• a

c e r t a i n p

• i

n t i n t i me . T r a c e s e t i s w r i t t e n t r a c e s ( P )

t r a c e s ( c

• i

n

• >

S T O P ) = { < > , < c

• i

n > } C L O C K = t i c k

• >

C L O C K t r a c e s ( C L O C K ) = { < > , < t i c k > , < t i c k , t i c k > , < t i c k , t i c k , t i c k > , … } = { t i c k } * E x a mp l e s : a

• >

b

• >

S T O P a

• >

S T O P A

• >

b

• >

S T O P S T O P

SLIDE 11

S e c r e c y a n d A u t h e n t i c a t i

• n

T

h e y a r e b

• t

h s a f e t y p r

• p

e r t i e s : a c e r t a i n b a d t h i n g s h

• u

l d n

• t

h a p p e n

S

e c r e c y : I n f

• r

ma t i

• n

m h a s n

• t

b e c

• me

k n

• w

n t

• t

h e i n t r u d e r

• A

u t h e n t i c a t i

• n

: T h e ma t c h i n g

• f

t h e s e t w

• e

v e n t s g u a r a n t e e s t h e i d e n t i t i e s

• f

Aa n d B

SLIDE 12

A u t h e n t i c a t i

• n

P r

• p

e r t y

B

I nt r

A

Commit wit h B Run wit h A

SLIDE 13

E x a mp l e : T h e Y a h a l

• m

P r

• t
• c
• l

T

h e p r

• t
• c
• l

M e s s a g e 1 a

• >

b : a . n

a

M e s s a g e 2 b

• >

s : b . { a . n

a

. n

b

}

S e r v e r K e y ( b )

M e s s a g e 3 s

• >

a : { b . k

a b

. n

a

. n

b

}

S e r v e r K e y ( a )

{ a . k

a b

}

S e r v e r K e y ( b )

M e s s a g e 4 a

• >

b : { a . k

a b

}

S e r v e r K e y ( b )

. { n

b

}

k a b

SLIDE 14

Y a h a l

• m P

r

• t
• c
• l

S A B a.na b.{ a.na.nb} ServerKey(b) { b.kab.na.nb} ServerKey(a). { a.kab} ServerKey(b) { a.kab} ServerKey(b).{nb} kab

SLIDE 15

# F r e e V a r i a b l e s

A , B : A g e n t S : S e r v e r n a , n b: N

• n

c e S K e y : A g e n t

• >S

e r v e r K e y k a b: S e s s i

• n

K e y I n v e r s e K e y s= ( S K e y , S K e y ) , ( k a b , k a b )

SLIDE 16

# P r

• c

e s s e s

I N I T I A T O R ( A , n a ) k n

• w

s S K e y ( A ) R E S P O N D E R ( B , S , n b ) k n

• w

sS K e y ( B ) S E R V E R ( S , k a b ) k n

• w

s S K e y

SLIDE 17

# P r

• t
• c
• l

d e s c r i p t i

• n

.

• >

A : B 1 . A

• >

B : n a 2 . B

• >

S : { A , n a , n b } { S K e y ( B ) } 3 a . S

• >

A : { B , k a b , n a , n b } { S K e y ( A ) } 3 b . S

• >

A : { A , k a b } { S K e y ( B ) } % e n c 4 a . A

• >

B : e n c % { A , k a b } { S K e y ( B ) } 4 b . A

• >

B : { n b } { k a b }

SLIDE 18

# S p e c i f i c a t i

• n

A g r e e me n t ( B , A , [ n a ] ) A g r e e me n t ( A , B , [ n a ] )

SLIDE 19

# A c t u a l v a r i a b l e s

A l i c e , B

• b

, M a l l

• r

y : A g e n t S a m : S e r v e r N a , N b: N

• n

c e K a b: S e s s i

• n

K e y I n v e r s e K e y s= ( K a b , K a b )

SLIDE 20

# I n l i n e f u n c t i

• n

s

s

y mb

• l

i cS K e y

SLIDE 21

# S y s t e m

I N I T I A T O R ( A l i c e , N a ) R E S P O N D E R ( B

• b

, S a m, N b ) S E R V E R ( S a m, K a b )

SLIDE 22

A u t h e n t i c a t i

• n

T

h e C S P a p p r

• a

c h i s b a s e d

• n

i n s e r t i n g s i g n a l s :

R

u n n i n g . a . b ( i n a ’s p r

• t
• c
• l

)

• A

g e n t ai s e x e c u t i n g a p r

• t
• c
• l

r u n a p p a r e n t l y w i t h b

C

• mmi

t . b . a ( i n b ’sp r

• t
• c
• l

)

• A

g e n t bh a s c

• mp

l e t e d a p r

• t
• c
• l

r u n a p p a r e n t l y w i t h a

A

u t h e n t i c a t i

• n

i s a c h i e v e di f R u n n i n g . a . ba l w a y s p r e c e d e s C

• mmi

t . b . ai n t h e t r a c e s

• f

t h e s y s t e m

We

a k e r

• r

s t r

• n

g e r f

• r

ms

• f

a u t h e n t i c a t i

• n

c a n b e a c h i e v e d b y v a r i a t i

• n

s

• f

t h e p a r a me t e r s

• f

t h e s e s i g n a l s a n d t h e c

• n

s t r a i n t s

• n

t h e m

SLIDE 23

A u t h e n t i c a t i

• n

i n t h e Y a h a l

• m

P r

• t
• c
• l

T

h e Y a h a l

• m P

r

• t
• c
• l

a i ms a t p r

• v

i d i n g a u t h e n t i c a t i

• n
• f

b

• t

h p a r t i e s : a u t h e n t i c a t i

• n
• f

t h e i n i t i a t

• r

t

• t

h e r e s p

• n

d e r , a n d v i c e v e r s a

We

w i l l a n a l y z e t h e t w

• a

u t h e n t i c a t i

• n

p r

• p

e r t i e s s e p a r a t e l y

T

h i s r e q u i r e s t w

• s

e p a r a t e e n h a n c e me n t s

• f

t h e p r

• t
• c
• l

SLIDE 24

Y a h a l

• m:

a u t h e n t i c a t i

• n
• f

i n i t i a t

• r

C

S P d e s c r i p t i

• n
• f

t h e t w

• p

a r t i e s

• E

n h a n c e d

I n i t i a t

• r

’( a , n

a)

=

e n v ? b : A g e n t s e n d . a . b . a . n

a

[ ]( r e c e i v e . J . a { b . k

a b

. n

a

. n

b

}

S e r v e r K e y ( a )

. m

k a bε K e y

s i g n a l . R u n n i n g _ I n i t i a t

• r

. a . b . n

a .

n

b .

k

a b n bε N

• n

c e

s e n d . a . b . m. { n

b

}

k a b m ε T

S e s s i

• n

( a , b , k

a b

, n

a

, n

b

) )

R e s p

• n

d e r ’( b , n

b)

=

[ ]( r e c e i v e . a . b . a . n

a s

e n d . b . J . b . { a . n

a

. n

b

}

S e r v e r K e y ( b ) k a bε K e y

r e c e i v e . a . b . { a . k

a b

}

S e r v e r K e y ( b )

. { n

b

}

k a b n bε N

• n

c e

s i g n a l . C

• mmi

t _ R e s p

• n

d e r . b . a . n

a .

n

b .

k

a b m ε T

S e s s i

• n

( b , a , k

a b

, n

a

, n

b

) )

SLIDE 25

Y a h a l

• m:

a u t h e n t i c a t i

• n
• f

i n i t i a t

• r

Initiatora Responderb Server

a.na b.{a.na.nb}ServerKey(b) {b.kab.na.nb}ServerKey(a) {a.kab}ServerKey(b) {a.kab}ServerKey(b) .{nb}kab Com_Resp.b.a.na.nb.kab Run_I nit .a.b.na.nb.kab

SLIDE 26

Y a h a l

• m:

a u t h e n t i c a t i

• n
• f

i n i t i a t

• r

T

h e p r

• p

e r t y t

• b

e v e r i f i e d :

s i g n a l . R u n n i n g _ I n i t i a t

• r

. a . b . n

a .

n

b .

k

a b

p r e c e d e s s i g n a l . C

• mmi

t _ R e s p

• n

d e r . b . a . n

a .

n

b .

k

a b

i n a l l t h e T r a c e s ( S y s t e m)

A

g a i n , t h i s p r

• p

e r t y c a n b e v e r i f i e d a u t

• ma

t i c a l l y b y c h e c k i n g t h e t r a c e s

SLIDE 27

Y a h a l

• m:

a u t h e n t i c a t i

• n
• f

i n i t i a t

• r

S p e c i f i c a t i

• n

A u t h e n t i c a t e I N I T I A T O R T

• R

E S P O N D E R A g r e e me n t

_ n a ( A ) = s i g n a l . R u n n i n g 2 . I N I T I A T O R _ r

• l

e . A ? B ? n a- > s i g n a l . C

• mmi

t 2 . R E S P O N D E R _ r

• l

e . B . A . n a- > S T O P

S y s t e m

S Y S T E M _ = ( A G E N T _ A l i c e [ | i n t e r ( A l p h a _ A l i c e , u n i

• n

( A l p h a _ B

• b

, A l p h a _ S a m) ) | ] ( A G E N T _ B

• b

[ | i n t e r ( A l p h a _ B

• b

, A l p h a _ S a m) | ] A G E N T _ S a m) ) S Y S T E M = S Y S T E M _ [ | { | c

• mm

, f a k e , i n t e r c e p t | } | ] I N T R U D E R

V e r i f i c a t i

• n

A s s e r t S p e c i f i c a t i

• n

[ T = S y s t e m

SLIDE 28

Y a h a l

• m:

a u t h e n t i c a t i

• n
• f

r e s p

• n

d e r

C

S P d e s c r i p t i

• n
• f

t h e t w

• p

a r t i e s

• E

n h a n c e d

I n i t i a t

• r

’( a , n

a)

=

e n v ? b : A g e n t s e n d . a . b . a . n

a

[ ]( r e c e i v e . J . a { b . k

a b

. n

a

. n

b

}

S e r v e r K e y ( a )

. m

k a bε K e y

s e n d . a . b . m. { n

b

}

k a b n bε N

• n

c e

• s

i g n a l . C

• mmi

t _ I n i t i a t

• r

. a . b . n

a .

n

b .

k

a b m ε T

S e s s i

• n

( a , b , k

a b

, n

a

, n

b

) )

R e s p

• n

d e r ’( b , n

b)

=

[ ]( r e c e i v e . a . b . a . n

a s

e n d . b . J . b . { a . n

a

. n

b

}

S e r v e r K e y ( b ) k a bε K e y

s i g n a l . R u n n i n g _ R e s p

• n

d e r . b . a . n

a .

n

b n bε N

• n

c e

r e c e i v e . a . b . { a . k

a b

}

S e r v e r K e y ( b )

. { n

b

}

k a b m ε T

S e s s i

• n

( b , a , k

a b

, n

a

, n

b

) )

SLIDE 29

Y a h a l

• m:

a u t h e n t i c a t i

• n
• f

r e s p

• n

d e r

Initiatora Responderb Server

a.na b.{a.na.nb}ServerKey(b) {b.kab.na.nb}ServerKey(a) {a.kab}ServerKey(b) {a.kab}ServerKey(b) .{nb}kab Run_Resp.b.a.na.nb. Run_I nit .a.b.na.nb.kab

SLIDE 30

Y a h a l

• m:

a u t h e n t i c a t i

• n
• f

r e s p

• n

d e r

T

h e p r

• p

e r t y t

• b

e v e r i f i e d :

s i g n a l . R u n n i n g _ R e s p

• n

d e r . b . a . n

a .

n

b

p r e c e d e s s i g n a l . C

• mmi

t _ I n i t i a t

• r

. a . b . n

a .

n

b .

k

a b

i n a l l t h e T r a c e s ( S y s t e m)

A

g a i n , t h i s p r

• p

e r t y c a n b e v e r i f i e d a u t

• ma

t i c a l l y b y c h e c k i n g t h e t r a c e s

SLIDE 31

Y a h a l

• m:

a u t h e n t i c a t i

• n
• f

r e s p

• n

d e r

S p e c i f i c a t i

• n

A u t h e n t i c a t e R E S P O N D E R T

• I

N I T I A T O R A g r e e me n t _ n a ( B ) =

s i g n a l . R u n n i n g 1 . R E S P O N D E R _ r

• l

e . B ? A ? n a- > s i g n a l . C

• mmi

t 1 . I N I T I A T O R _ r

• l

e . A . B . n a- > S T O P

S y s t e m

S Y S T E M _ = ( A G E N T _ A l i c e [ | i n t e r ( A l p h a _ A l i c e , u n i

• n

( A l p h a _ B

• b

, A l p h a _ S a m) ) | ] ( A G E N T _ B

• b

[ | i n t e r ( A l p h a _ B

• b

, A l p h a _ S a m) | ] A G E N T _ S a m) ) S Y S T E M = S Y S T E M _ [ | { | c

• mm

, f a k e , i n t e r c e p t | } | ] I N T R U D E R

V e r i f i c a t i

• n

A s s e r t S p e c i f i c a t i

• n

[ T = S y s t e m