An analysis of the applicability of blockchain to secure IP addresses allocation, delegation and bindings draft-paillisse-sidrops-blockchain-01

Transcription

1 An analysis of the applicability of blockchain to secure IP addresses allocation, delegation and bindings draft-paillisse-sidrops-blockchain-01 OPSEC - IETF London March 2018 Jordi Paillissé, Albert Cabellos, Vina Ermagan, Alberto Rodríguez, Fabio Maino jordip@ac.upc.edu 1

2 A short Blockchain tutorial 2

3 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 3

4 Blockchain - Transactions Transaction Sender s Public Key Sender s signature Data 4

5 Blockchain - Transactions Transaction Sender s Public Key Sender s signature Data 1 Transactions are broadcasted to all the nodes P2P network 5

6 Blockchain - Transactions Transaction Sender s Public Key Sender s signature Data 1 Transactions are broadcasted to all the nodes P2P network 2 A node collects transactions into a block Block Previous Hash Transactions 1 N 6

7 Blockchain - Transactions Transaction Sender s Public Key Sender s signature Data 1 Transactions are broadcasted to all the nodes P2P network 2 A node collects transactions into a block 3 Compute consensus algorithm Block Previous Hash New Block Previous Hash Transactions 1 N Transactions 1 N 7

8 Blockchain - Transactions Transaction Sender s Public Key 1 Transactions are broadcasted to all the nodes Sender s signature P2P network Data 2 A node collects transactions into a block 3 Compute consensus algorithm 4 Broadcast new block to the network Block Previous Hash New Block Previous Hash Transactions 1 N Transactions 1 N 8

9 Blockchain - Transactions Transaction Sender s Public Key 1 Transactions are broadcasted to all the nodes Sender s signature P2P network Data 2 A node collects transactions into a block 3 Compute consensus algorithm 4 Broadcast new block to the network Block Previous Hash New Block Previous Hash 5 The other nodes verify the consensus algorithm and accept the block Transactions 1 N Transactions 1 N 9

10 Summary of features vs. traditional PKI systems Advantages Decentralized No CAs Simplified management Simple rekeying Limited prior trust Auditable Censorship-resistant Drawbacks No crypto guarantees Large storage Costly bootstrapping 10

11 Blockchain for IP addresses 11

12 Data in the blockcahin We want to store: Prefix: 10/8 Holder: P+ Prefix: 10/8 Holder: P1+ new holder Prefix: 10/8 AS#: IP address block + Holder Prefix: 10/8 Holder: P2+ Prefix: 10/8 Holder: P3+ new holder IP address block + AS number Chain of allocations and delegations 12

13 IP addresses vs. coins IP addresses = coins Similar properties: Unique Transferrable Divisible Exchange blocks of IP addresses just like coins 13

14 Example 14

15 Allocation From: IANA To: IANA I have all prefixes blockchain n n+1 n+2 15

16 Allocation From: IANA To: IANA I have all prefixes Allocation From: IANA To: APNIC Prefix 1/8 for APNIC blockchain n n+1 n+2 16

17 Allocation From: IANA To: IANA I have all prefixes Allocation From: IANA To: APNIC Prefix 1/8 for APNIC Delegation From: APNIC To: ISP A ISP A has 1.2/16 blockchain n n+1 n+2 17

18 Allocation From: IANA To: IANA I have all prefixes Allocation From: IANA To: APNIC Prefix 1/8 for APNIC Delegation From: APNIC To: ISP A ISP A has 1.2/16 Binding From: ISP A To: ISP A Bind 1.2/16 to AS # blockchain n n+1 n+2 18

19 Allocation From: IANA To: IANA I have all prefixes Allocation From: IANA To: APNIC Prefix 1/8 for APNIC Delegation From: APNIC To: ISP A ISP A has 1.2/16 Binding From: ISP A To: ISP A Bind 1.2/16 to AS # blockchain n n+1 n+2 Who has 1.2/16? AS# From: ISP A To: ISP A Bind 1.2/16 to AS #

20 Allocation From: IANA To: IANA I have all prefixes Allocation From: IANA To: APNIC Prefix 1/8 for APNIC I can go back to check if this prefix Delegation was originally owned by Binding IANA From: APNIC To: ISP A ISP A has 1.2/16 From: ISP A To: ISP A Bind 1.2/16 to AS # blockchain n n+1 n+2 Who has 1.2/16? AS# From: ISP A To: ISP A Bind 1.2/16 to AS #

21 Operational Considerations 21

22 Revocation Traditional PKIs Centralized control Bitcoin Decentralized control Lost keys Compromised keys Improper use 22

23 Revocation Traditional PKIs Centralized control Bitcoin Decentralized control Middle ground: Timeout transfer to previous owner Multi-signature more than one key Revocation tx. by a third party 23

24 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) From: keya To: keyb Prefix 1/8 Other transactions 24

25 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) From: keya To: keyb Prefix 1/8 Other transactions From: keyb To: keyc Prefix 1/8 Controlled by the same entity 25

26 Privacy Lawful interception RIR policies Business relationships Public Private Blockchain (IP prefix1, pubkey1) (IP prefix2, pubkey2) Internal RIR policies 26

27 Privacy Lawful interception RIR policies Business relationships Public Blockchain (IP prefix1, pubkey1) (IP prefix2, pubkey2) Update (prefix, key) pair Private Internal RIR policies 27

28 Prototype 28

29 _pythons_flying_circus_uk Prototype Python Features: Simple Proof of Stake Block time 60s 2 MB blocks IPv4 and IPv6 Open-sourced: ckchain-mapping-system 29

30 Experiment Master Genesis block 0/0 0::/0 1-Allocate all /10 8 nodes 30

31 Experiment Master Genesis block 0/0 0::/0 1-Allocate all /10 2-Allocate all /16 8 nodes 3-Allocate ~130k prefixes* *Extracted from RIR statistics exchange files, eg. ftp://ftp.apnic.net/pub/stats/apnic/delegated-apnic-extended-latest 31

32 Processed ~160k transactions 32

33 3-Allocate ~130k prefixes 2-Allocate all /16 1-Allocate all /10 Processed ~160k transactions 33

34 34

35 35

36 Thanks for listening! 36

37 Scalability Approx. 600 GB in 2034 (IP blocks + AS bindings) 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: 37

38 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 *Nakamoto, S. (2008). Bitcoin: A peer-to-peer electronic cash system. Sec. 8 38

39 Transaction examples 39

40 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 New Transaction Hash(P+ root)= Root@1 I own all the address space Root@2 40

41 Prefix allocation and delegation Root allocates blocks of addresses to other entities (identified by Hash(Public Key)) by adding transactions New Transaction allocate (rest of space) 0.0/ /8 Holders can further delegate address blocks to other entities New Transaction delegate (rest of space) 0.0.1/ /24 41

42 Writing AS bindings Just like delegating a prefix, but instead of the new holder, we write the binding New Transaction Deleg3@ binding 0.0.1/24 from AS#

43 External server authentication Some information may not be suitable for the blockchain, or changes so fast it is already outdated 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 43

44 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! 44