EVIA: Efficient and Verifiable In- Network Aggregation in Sensor Networks

Transcription

1 EVIA: Effcent and Verfable In- Network Areaton n Sensor Networks Yu-Shan Chen Wednesday, June 20, 2007

2 In-Network Areaton I stole ths slde fro Chan@CMU +15 Sensor readns Q What s the su of all the sensor readns? Answer:

3 Correct Data Areaton Aan! I stole ths slde fro Chan@CMU Q

4 Sensor Readn Falsfcaton Yes..It s stll stolen Q Malcous node reports false sensor readn wthn leal bounds 2 3

5 What s EVIA? Where s EVIA?

6 EVIA Execute SUM areaton n snlepass Verfy the exact result Optally secure Low councaton Lht coputaton

7 Pror Related Work SIA by Przydatek, Perr, & Son [2003] Flat topoloy snle areator Merkle hash tree Interactve checkn bt. Q & A Probablstc Proof sketch by Garofalaks, Hellersten & Manats [2006] FM-sketch Authentcaton anfests Probablstc COUNT-based SHINA by Chan, Perr & Son [2006] Merkle hash tree Herarchcal SUM-based Result-checkn accoplshed by all sensor nodes

8 Proof Sketches Approxated results FM-sketches Duplcate nsenstve Snle pass

9 SHINA Areaton Tree Cotent Tree M A B C D M R M F E M F M E E M A B D M C M A B C D M D M A B C M A B M B M C A M A A; v A M B B ; v B M A M A B hm A jjm B ; v A + v B M A B C D hm A B jjm D jjm C ; v A B + v D + v C }va B

10 [M R ]: Querer sns on M R M F R v ABCDF,M ABCD,M F,[M R ] v EF,M E,M F,[M R ] E M E M F D M A B C D v CD,v EF,M C, M D,M E,M F,[M R ] v ABD,v EF,M AB, M D,M E,M F,[M R ] v B,v CD,v EF,M B, M C, M D,M E,M F,[M R ] M A B B M D M C C M A A M B hv ABCDEF,hv ABCD, hv A +v B,hM A M B M C M D M E M F M R

11 Verfy MACK OK MACK E OK E M E F M R MACK F OK M F MACK A OK MACK B OK MACK C OK MACK D OK D M A B C D MACK A OK MACK B OK MACK C OK M A B B MACK D OK M D M C C MACK A OK M A MACK B OK A M B

12 SHINA Pro Optally secure Unless coprose the sensor nodes, not possble to falsfy data of others whle areaton. Lht coputaton Hash Messae Authentcaton Code Con 2 rounds More coneston to low level nodes Dstrbute the verfcaton to each node

13 Motvaton As optally secure as SHINA Make sure nteredate nodes are not able to subvert downstrea data Encrypt the data then areate the cphertext Hooorphc encrypton Naturally alleable Sn on the data then areate the snatures Reular snature schees are not lnear.

14 Why not hooorphc encrypton.. Hooorphc encrypton E: encrypton by querer s publc key E1 E2 E1+2 Only querer can decrypt Areator can perfor w/o known Areator lose otvaton But areator can perfor E too E Ed E+d

15 EVIA Defne a specfc snature schee Make snature areaton possble and secure The fnal snatures areaton looks lke a snle snature enerated by all nodes toether.

16 Settn Two lare pres p >1024 bts, q >160 bt and qkp-1. A enerator n Z p. Let k. The data of node. x y od p

17 Trck a c a c+ b d + b d 1od q od p a c+ b d od p a c+ b d od p a c b d od p Prvate keys Snature of

18 Settn The Querer Pck aster secret keys c, d for tself. Pck plct prvate key a, b for node. a c + b d α b β Store prvate keys α, β nto node before deployent a 1od q

19 Areaton Areaton Sensor node Areator node j s r β α j ch j ch j j ch j ch j j ch j s s r r β α

20 Verfcaton Verfcaton d l c l s r * * + + b d c a b d c a d b c a d c s r

21 Coputaton Effcency Sensor node 2 exponentaton Areator node 1 *#chldren suaton, 2*#chldren ultplcaton Querer 2 exponentaton, 1 ultplcaton

22 Councaton Effcency Payload sze +2 p 32 bts + 2*1024 bts Swtch to Ellptc Curve Cryptosyste +2 q 32 bts + 2*160 bts Snle Round!

23 But It doesn t work. The snature s alleable r r 1/ α α r ' r 3 3 α α 3

24 Fx t up Querer stores ore secret key nto nodes before deployent The offset secret keys δ for node. The snature s on shfted data v nstead of. v r s α β + v v δ

25 Verfcaton Verfcaton Alost the sae s r v v v b d c a d b v c v a d v b c v a d c δ δ s r d l c l δ * *

26 To be ore secure.. Offset vary fro query to query δ hash Query# γ Forward secrecy δ hash Query# δ, t 1, t

27 Proof Proof n every query. snature snce the offsets are dfferent leal t's nfeasble to ake a,, Gven any,,, t's nfeasble to derve,,, Gven a s r r b a s r δ δ α β α + +

28 Features Areate snatures Snle pass Low councaton < half SHIDA Exact data values

29 Naah Naah {ssn nodes} * * * * k k s r s r d l c l d l c l δ δ δ Nonsense! It s coplete practcal! Soe nodes ht not alve. Too deal to assue Q knows who are reachable. My excuse: h. Other areaton schees have the sae assupton.

30 A possble way. Is there any ethod slar to proof sketches whch can areate the d of alve nodes and ake a sketch to Q, shown who are probably out of servce. Bloo flter? Could be possble but On sketch?! Need not to be an exactly accurate sketch. An Olo n sze sketch ndcatn <Onlon possble cobnatons s ood enouh!

31 If the querer ets Onlon possble cobnatons of ssn nodes, r * l c s * l δ d δ k k {ssn nodes} t can test the cobnatons n Onlon.

32 Next. Make MIN/MAX to be one-pass COUNT, AVERAGE s trval. MIN/MAX based on COUNT. Duplcate nsenstve Cooperaton between close sensor nodes Locate the ssn nodes!