# shw2 - IS2150/TEL2810 Introduction to Security Fall 2011...

This preview shows pages 1–5. Sign up to view the full content.

IS2150/TEL2810 Introduction to Security - Fall 2011 Homework 2: Sample Solution Question 1

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
Question 2-a Step 1: Step 2: Step 3: V 1 V 3 V 2 V 4 V 5 V 6 {g} {a 3 ,a 6 ,a 10 ,g} {a 8 ,g} {a 2 ,a 4 ,a 5 ,a 7 ,g} {a 1 ,a 9 ,g} V 1 V 3 V 2 V 4 V 5 V 6 {g} {a 3 } {a 8 ,g} {a 2 ,a 4 ,a 5 ,a 7 ,g} {a 1 ,a 9 ,g} {a 8 } {a 10 } {a 6 } {a 9 } {a 5 } {a 7 } V 1 V 3 V 2 V 4 V 5 V 6 {a 3 } {a 2 } {a 1 } {a 8 } {a 10 } {a 6 } {a 9 } {a 5 } {a 7 }
Question 2-b Access sets: A(x)={x,a1,a2,a3} A(a1)={a1,a2,a3} A(a2)={a2,a3} A(a3)={a3} A(b)={a3,b,c} A(c)={c,d} A(d)={d} A(e)={d,e} Deletion sets: δ(x,a1)={a1} δ(x,a2)={a2} δ(x,a3)={a3} δ(a1,a2)={a2} δ(a1,a3)={a3} δ(a2,a3)={a3} δ(a3,b)={a3} δ(b,c)={c} δ(c,d)={d} δ(c,e)={d} δ(d,e)={d} Conspiracy graph: Theft of r by x: Conspirators set: {x,a3,b,c,e} Witness: 1. e grants (r to z) to d 2. c takes (r to z) from d 3. b gets (r to z) from c (Lemma 3-2) a. b creates (tg to new vertex) t1 b. b grants (g to t1) to c c. c grants (r to z) to t1 d. b takes (r to z) from t1 4. b grants (r to z) to a3 5. x takes (t to a2) from a1 6. x takes (g to a3) from a2 7. x gets (r to z) from a3 (Lemma 3-2) a. x creates (tg to new vertex) t2 b. x grants (g to t2) to a3 c. a3 grants (r to z) to t2 h(x) h(a1) h(a2) h(a3) h(b) h(c) h(d) h(e)

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
d. x takes (r to z) from t2
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

### Page1 / 7

shw2 - IS2150/TEL2810 Introduction to Security Fall 2011...

This preview shows document pages 1 - 5. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online