Luca Maria Aiello, Università degli Studi di Torino, Computer Science department 1 Tempering Kademlia with a robust identity based system

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


PeeR-to-peer beyOnd FILE Sharing

CataniaFirenzeParmaPaviaRomaTorinoTrento

Security onp2p networks


Goal

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

a. Scalabilityb. Complete decentralizationc. Efficiency

Preserving:


Steps

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

+f. Identity Based Cryptography


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


Attacks against DHTs

a. Storage attacks

b. Routing attacks

c. DDoS attacks

e. Man In The Middle

d. Sybil attack


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


Current DHT designs

PastryChord Tapestry

KademliaCAN Viceroy


Kademlia

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

b. Routing messages piggybacking

c. Lightweight join phase

d. XOR metric

e. Caching


Kademlia: applications

Vuze Bittorrent eMule Limewire Retroshare


Likir

Layered Id-based Kademlia InfRastructure

Problema: loose binding between node and identity

Soluzione: a certification service

Sfida: preserving the p2p paradigm pureness


Likir: architecture


Likir: initialization


Likir: node session


Likir: content STORE

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


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


Identity 2.0

+


VERIFIED

Identity 2.0


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

Identity Based Signature

Schema IBS di Boneh Franklyn (2001)


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


Performance evaluation


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


Implementation


Conclusions

Kademlia + Identity support +

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

Likir__

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

Questions?

Documents

Luca Maria Aiello, Università degli Studi di Torino, Computer Science department 1 Tempering Kademlia with a robust identity based system