BGP Blockchain

There have been many proposed solutions to help secure the Border Gateway Protocol (BGP) including securing TCP, CoPP, IPSec, Secure BGP, Route Origination Validation (ROV), BGPSec along with many variations. Could we also use Blockchain to secure BGP? This document provides a review of how Blockchain could be used to secure BGP particularly as supplemental to existing solutions. Many of the proposals can be extended to any routing protocol but the focus here is with BGP. The potential attractiveness of adding Blockchain to BGP is that it adds additional security without changes to the BGP protocol. This analysis does not consider external factors such as the energy demands of deploying such solutions.

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119.

There are various ways Blockchain could be used to help secure BGP that we will explore in this section.

Prefix origin announcements could be stored on a blockchain to avoid BGP human configuration errors or hijacks. The consensus algorithms will ensure that everyone knows the correct owner AS of the prefix and everyone will know if there is an unauthorized change attempt. The existing RPKI system could be used to to authorize prefix owners and then an additional step could be to treat that as a transaction to be stored on a blockchain. ROA entries could be added to a blockchain as secure transactions and those transactions would be relied upon by route validators as authoritative. Perhaps blockchain validation information could be added as a new ROA field.

This is very similar to the previous solution. If using RPKI, route validators could cross check with the BGP blockchain before sending authorized prefix/AS matches to relying BGP routers. If not using RPKI, then routers would need to check a IRR blockchain prefix/AS database, if one were to exist, in order to validate incoming BGP updates.

In addition to the prefix to AS match information being stored on a blockchain, the routing policy of those routes could also be stored on the blockchain. As long as the policy was correctly added to the chain, the path policies cannot be altered except by those authenticated to do so.

Blockchain could also be used to store configuration files within an AS in order to prevent malicious config tampering and to prevent misconfiguration. This protection could be provided within a private blockchain environment where only authorized users have access to the blockchain data. This could also be used within a trusted external peering environment to build a distributed database of BGP files such as communities for use between BGP neighbors. Peers can use the data in the blockchain to understand the necessary peering relationship and act on the communities in a consistent manner.

BGP stores multiple paths to a destination in the BGP table. The BGP table contains all of the routes from all of the neighbors. Only the best route gets installed in the routing table. To help further secure the BGP table, all of those routes/paths could be installed in a blockchain. Some mechanism could be used to validate these routes/paths, that reside in the blockchain, prior to one being selected as the path path in the routing table. This could also be extended to provide proof of transit across certain expected paths.

BGP-LS is used to provide BGP topology information to a Controller. That topology information could be added to a blockchain to ensure that the topology data is not compromised. PCEP, or other protocol, could be used by a controller to validate any update of a BGP forwarding table using this same (or separate) blockchain. The latest forwarding rules would be maintained in a distributed blockchain which is built using BGP-LS data and authorized users as an input. Without the proper credentials it would be very difficult to update the forwarding rules in the blockchain and a record would be kept with all update attempts.

The attractiveness of Blockchain applications, such as Bitcoin and Ethereum, are that they are highly decentralized and more resistant to attack. This has opened the way for securing monetary transactions using crytocurrencies and their underlying blockchain technology. Blockchains mining power, however, is centralized with mining pools concentrating within certain regions and Autonomous Systems. This also creates a more centralized routing situation which could become vulnerable to BGP vulerabilities where IP addresses of the mining pools are hijacked. Therefore helping to further secure BGP will help to secure blockchain's centralized mining pools.

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There could be new blockchain related attacks that BGP would experience if blockchain were to be added into BGP's policy system. These attacks include trying to replace the trusted chain with a fradulent chain. We will explore some of those here or in a new draft.