An analysis of the applicability of blockchain to secure IP - - PowerPoint PPT Presentation

An analysis of the applicability

• f blockchain to secure IP

addresses allocation, delegation and bindings

draft-paillisse-sidrops-blockchain-01

OPSEC - IETF 101 - London March 2018

Jordi Paillissé, Albert Cabellos, Vina Ermagan, Alberto Rodríguez, Fabio Maino

jordip@ac.upc.edu

http://openoverlayrouter.org

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A short Blockchain tutorial

2

Blockchain - Introduction

• Blockchain:

– Decentralized, secure and trustless database – Token tracking system (who has what)

• Add blocks of data one after another
• Protected by two mechanisms:

– Chain of signatures – Consensus algorithm

• First appeared: Bitcoin, to exchange money
• Other applications are possible

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Blockchain - Transactions

4

Sender’s Public Key Sender’s signature Transaction Data

Blockchain - Transactions

5

Sender’s Public Key Sender’s signature Transaction Data Transactions are broadcasted to all the nodes

P2P network

1

Blockchain - Transactions

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Sender’s Public Key Sender’s signature Transaction Data Previous Hash

Transactions 1 ··· N Block

Transactions are broadcasted to all the nodes

2

A node collects transactions into a block

P2P network

1

Blockchain - Transactions

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Sender’s Public Key Sender’s signature Transaction Data Transactions are broadcasted to all the nodes

2

A node collects transactions into a block

3

Compute consensus algorithm

P2P network

1

Transactions 1’ ··· N’ New Block

Previous Hash

Transactions 1 ··· N Block

Previous Hash

Blockchain - Transactions

8

Sender’s Public Key Sender’s signature Transaction Data Transactions are broadcasted to all the nodes

2

A node collects transactions into a block

P2P network

1 4

Broadcast new block to the network

3

Compute consensus algorithm

Transactions 1’ ··· N’ New Block

Previous Hash

Transactions 1 ··· N Block

Previous Hash

Blockchain - Transactions

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Sender’s Public Key Sender’s signature Transaction Data Transactions are broadcasted to all the nodes

2

A node collects transactions into a block

5

The other nodes verify the consensus algorithm and accept the block

P2P network

1 4

Broadcast new block to the network

3

Compute consensus algorithm

Transactions 1’ ··· N’ New Block

Previous Hash

Transactions 1 ··· N Block

Previous Hash

Summary of features

Advantages

• Decentralized
• No CAs
• Simplified management
• Simple rekeying
• Limited prior trust
• Auditable
• Censorship-resistant

Drawbacks

• No crypto guarantees
• Large storage
• Costly bootstrapping

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• vs. traditional PKI systems

Blockchain for IP addresses

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Data in the blockcahin

We want to store:

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Prefix: 10/8 Holder: P+ IP address block + Holder IP address block + AS number Prefix: 10/8 AS#: 12345 Prefix: 10/8 Holder: P1+ Prefix: 10/8 Holder: P2+ Prefix: 10/8 Holder: P3+ Chain of allocations and delegations

new holder new holder

IP addresses vs. coins

• IP addresses = coins
• Similar properties:

– Unique – Transferrable – Divisible

• Exchange blocks of IP addresses just like

coins

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Example

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1 2 3

4 5 6

7 ... n n+1 n+2

blockchain

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From: IANA To: IANA I have all prefixes

Allocation

1 2 3

4 5 6

7 ... n n+1 n+2

blockchain

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From: IANA To: IANA I have all prefixes From: IANA To: APNIC Prefix 1/8 for APNIC

Allocation Allocation

1 2 3

4 5 6

7 ... n n+1 n+2

blockchain

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From: IANA To: IANA I have all prefixes From: IANA To: APNIC Prefix 1/8 for APNIC From: APNIC To: ISP A ISP A has 1.2/16

Allocation Allocation Delegation

1 2 3

4 5 6

7 ... n n+1 n+2

blockchain

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From: IANA To: IANA I have all prefixes From: IANA To: APNIC Prefix 1/8 for APNIC From: APNIC To: ISP A ISP A has 1.2/16 From: ISP A To: ISP A Bind 1.2/16 to AS # 12345

Allocation Binding Allocation Delegation

1 2 3

4 5 6

7 ... n n+1 n+2

blockchain Who has 1.2/16? AS# 12345

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From: IANA To: IANA I have all prefixes From: IANA To: APNIC Prefix 1/8 for APNIC From: APNIC To: ISP A ISP A has 1.2/16 From: ISP A To: ISP A Bind 1.2/16 to AS # 12345

Allocation Binding Allocation Delegation

From: ISP A To: ISP A Bind 1.2/16 to AS # 12345

1 2 3

4 5 6

7 ... n n+1 n+2

blockchain Who has 1.2/16? AS# 12345

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From: IANA To: IANA I have all prefixes From: IANA To: APNIC Prefix 1/8 for APNIC From: APNIC To: ISP A ISP A has 1.2/16 From: ISP A To: ISP A Bind 1.2/16 to AS # 12345

Allocation Binding Allocation Delegation

From: ISP A To: ISP A Bind 1.2/16 to AS # 12345

I can go back to check if this prefix was originally owned by IANA

Operational Considerations

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Revocation

• Lost keys
• Compromised keys
• Improper use

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Traditional PKIs Bitcoin

Decentralized control Centralized control

Revocation

Middle ground:

• Timeout  transfer to previous owner
• Multi-signature  more than one key
• Revocation tx.  by a third party

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Traditional PKIs Bitcoin

Decentralized control Centralized control

Rekeying

• Delegating the block of addresses to itself using

a new key pair.

• Simpler than traditional rekeying schemes
• Can be performed independently (each holder

can do it without affecting other holders)

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From: keyA To: keyB Prefix 1/8 Other transactions…

Rekeying

• Delegating the block of addresses to itself using

a new key pair.

• Simpler than traditional rekeying schemes
• Can be performed independently (each holder

can do it without affecting other holders)

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From: keyA To: keyB Prefix 1/8 From: keyB To: keyC Prefix 1/8 Other transactions…

Controlled by the same entity

Privacy

• Lawful interception
• RIR policies
• Business relationships

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Internal RIR policies Blockchain (IP prefix1, pubkey1) (IP prefix2, pubkey2) …

Public Private

Privacy

• Lawful interception
• RIR policies
• Business relationships

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Internal RIR policies Blockchain (IP prefix1, pubkey1) (IP prefix2, pubkey2) …

Public Private

Update (prefix, key) pair

Prototype

28

Prototype

• Python
• Features:

– Simple Proof of Stake – Block time 60s – 2 MB blocks – IPv4 and IPv6

• Open-sourced:

https://github.com/OpenOverlayRouter/blo ckchain-mapping-system

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http://sharetv.com/shows/monty _pythons_flying_circus_uk

Experiment

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Master 8 nodes

1-Allocate all /10

Genesis block 0/0 0::/0

Experiment

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Master 8 nodes

1-Allocate all /10 3-Allocate ~130k prefixes*

*Extracted from RIR statistics exchange files, eg. ftp://ftp.apnic.net/pub/stats/apnic/delegated-apnic-extended-latest

2-Allocate all /16

Genesis block 0/0 0::/0

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Processed ~160k transactions

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Processed ~160k transactions

1-Allocate all /10 3-Allocate ~130k prefixes 2-Allocate all /16

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Thanks for listening!

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Scalability

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• One AS <> prefix binding for each block of /24 IPv4 address space
• Growth similar to BGP churn*
• Each transaction approx. 400 bytes
• Only IP Prefixes: worst case + BGP table growth*: approx. 40 GB in 20

years

• With PoS, storage can be reduced

*Source: http://www.potaroo.net/ispcol/2017-01/bgp2016.html

• Approx. 600 GB in 2034

(IP blocks + AS bindings)

Storage

• Several mechanisms can help reducing

storage, eg:

– Prune old transactions – Download only headers (Bitcoin SPV*) – Discard old blocks

• These techniques depend on the

consensus algorithm

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*Nakamoto, S. (2008). Bitcoin: A peer-to-peer electronic cash system. Sec. 8

Transaction examples

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First transaction

• Users trust the Public Key of the Root, that

initially claims all address space by writing the genesis block

• Root can delegate all address space to itself

and use a different keypair

“I own all the address space” Hash(P+ root)= Root@1 Root@2 New Transaction

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Prefix allocation and delegation

• Root allocates blocks of addresses to other

entities (identified by Hash(Public Key)) by adding transactions

“allocate” Root@2 Root@3 (rest of space) New Transaction 0.0/16 Deleg1@ 25.5.5/8 Deleg2@

• Holders can further delegate address blocks to
• ther entities

“delegate” Deleg1@ Deleg1@2 (rest of space) New Transaction 0.0.1/24 Deleg3@ 0.0.2/24 Deleg4@

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Writing AS bindings

• Just like delegating a prefix, but instead of the

new holder, we write the binding

“binding” Deleg3@ New Transaction 0.0.1/24 from AS# 12345

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External server authentication

• Some information may not be suitable for the

blockchain, or changes so fast it is already

• utdated when added into a block
• A public key from an external server can also be

included in the delegations

• Since blockchain provides authentication and

integrity for this key, parties can use it to authenticate responses from the external server

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FAQ

• Does it grow indefinitely?

– Yes

• Do all nodes have the same information?

– Yes

• When answering a query, do you have to

search the entire blockchain?

– No, you can create a separate data structure only with the current data

• If I lose my private key, do I lose my prefixes

also?

– Yes, watch out!

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