luca maria aiello, università degli studi di torino, computer science department 1 tempering...

Luca Maria Aiello, Università degli Studi di Torino, Computer Science department 1

Tempering Kademlia with a Tempering Kademlia with a robust identity based systemrobust identity based system

Luca Maria Aiello, Università degli Studi di Torino, Computer Science department 2

PeeR-to-peer beyOnd FILE Sharing

CataniaFirenzeParmaPaviaRomaTorinoTrento

Security onp2p networks

Luca Maria Aiello, Università degli Studi di Torino, Computer Science department 3

Goal

Design and implementation of a DHT middleware resistant to most known overlay attacks

a. Scalabilityb. Complete decentralizationc. Efficiency

Preserving:

Luca Maria Aiello, Università degli Studi di Torino, Computer Science department 4

Steps

a. Analysis of DHT security issuesb. Overview on existing DHTs propertiesc. Secure protocol (and architecture) designd. Performance analisyse. Implementation

+f. Identity Based Cryptography

Luca Maria Aiello, Università degli Studi di Torino, Computer Science department 5

Distributed Hash Tables

b. Overlay network

c. Keyspace

d. Key-node binding

e. Key-content binding

f. Responsibility function

g. Lookup in O(log(N)) steps

a. Content storage

Luca Maria Aiello, Università degli Studi di Torino, Computer Science department 6

Attacks against DHTs

a. Storage attacks

b. Routing attacks

c. DDoS attacks

e. Man In The Middle

d. Sybil attack

Luca Maria Aiello, Università degli Studi di Torino, Computer Science department 7

Applying countermeasures

a. Random NodeIds

b. Few nodes per user

c. Verifiable node identity

d. Secure communication protocol

e. Safe bootstrap

No existent DHT grants these features

Luca Maria Aiello, Università degli Studi di Torino, Computer Science department 8

Current DHT designs

PastryChord Tapestry

KademliaCAN Viceroy

Luca Maria Aiello, Università degli Studi di Torino, Computer Science department 9

Kademlia

a. Simple protocol (ping, store, find-node, find-value)

b. Routing messages piggybacking

c. Lightweight join phase

d. XOR metric

e. Caching

Luca Maria Aiello, Università degli Studi di Torino, Computer Science department 10

Kademlia: applications

Vuze Bittorrent eMule Limewire Retroshare

Luca Maria Aiello, Università degli Studi di Torino, Computer Science department 11

Likir

Layered Id-based Kademlia InfRastructure

Problema: loose binding between node and identity

Soluzione: a certification service

Sfida: preserving the p2p paradigm pureness

Luca Maria Aiello, Università degli Studi di Torino, Computer Science department 12

Likir: architecture

Luca Maria Aiello, Università degli Studi di Torino, Computer Science department 13

Likir: initialization

Luca Maria Aiello, Università degli Studi di Torino, Computer Science department 14

Likir: node session

Luca Maria Aiello, Università degli Studi di Torino, Computer Science department 15

Likir: content STORE

All RPC used are the same defined in Kademlia.We customize only the STORE:

Luca Maria Aiello, Università degli Studi di Torino, Computer Science department 16

Likir: Security properties

Routing Storage / DDOSSybil MITM

a. Random generated NodeIds

b. Verifiable identity No masquerading Account binded to every node ID-based applications integration

c. Credentials binded to contents Verifiable ownership Reputation + Blacklisting

d. Secure communication protocol Resistant to interleaving attacks

SPoF

e. The Certification Service is contected only ONCE

Luca Maria Aiello, Università degli Studi di Torino, Computer Science department 17

Identity 2.0

+

Luca Maria Aiello, Università degli Studi di Torino, Computer Science department 18

VERIFIED

Identity 2.0

Luca Maria Aiello, Università degli Studi di Torino, Computer Science department 19

1.Setup → 2.Extract → 3.Sign → 4.Verify

Identity Based Signature

Schema IBS di Boneh Franklyn (2001)

Luca Maria Aiello, Università degli Studi di Torino, Computer Science department 20

Likir & IBS: evaluation

Need of a Private Key Generator

Key Escrow

Signature generation and check is slower than RSA

Identity 2.0 compliant

The public key can be omitted

Signatures are smaller than in RSA

Luca Maria Aiello, Università degli Studi di Torino, Computer Science department 21

Performance evaluation

Luca Maria Aiello, Università degli Studi di Torino, Computer Science department 22

Performance evaluation

a. JLikir, Java 1.6b. Kademlia adhering c. CS implemented like a CAd. Index Side Filteringe. We used JLikir to develop LiCha

− Privacy-aware instant messaging application− Fully decentralized service− Likir identity support is fully exploited− High privacy and security level

Luca Maria Aiello, Università degli Studi di Torino, Computer Science department 23

Implementation

Luca Maria Aiello, Università degli Studi di Torino, Computer Science department 24

Conclusions

Kademlia + Identity support +

Protection from attacks = —————————————

Likir__

Luca Maria Aiello, Università degli Studi di Torino, Computer Science department 25Likir monastery, Ladakh

Questions?