Liveness in consensus protocol

Patent metadata

Field	Value
Publication number	US-12335304-B2
Application number	US-202418603926-A
Country	US
Kind code	B2
Filing date	Mar 13, 2024
Priority date	Mar 14, 2023
Publication date	Jun 17, 2025
Grant date	Jun 17, 2025

Abstract

Various aspects of the subject technology relate to systems, methods, and machine-readable media for enhancing liveness in a blockchain. Various aspects may include running a first consensus protocol. Aspects may also include detecting a liveness attack in the first consensus protocol. Aspects may also include suspending, when the liveness attack is detected, acceptance of new blocks in the first consensus protocol. Aspects may also include broadcasting a preferred block and identifying a highest accepted block in the set of nodes from running the first consensus protocol based on the preferred block. Aspects may also include transitioning from the first consensus protocol to the second consensus protocol and running the second consensus protocol until a consensus value or a new accepted block is decided. Aspects may also include reinstating and resuming running the first consensus protocol based on the new accepted block.

First claim

What is claimed is:

1. A computer-implemented method for implementing transition protocols, comprising:
running a first consensus protocol in a set of nodes of a blockchain network;
detecting a liveness attack in the first consensus protocol at a node in the set of nodes;
initiating, based on detecting the liveness attack, a transition protocol enabling a transition from the first consensus protocol to a second consensus protocol;
suspending, when the liveness attack is detected, acceptance of new blocks in the first consensus protocol;
identifying a highest accepted block in the set of nodes from running the first consensus protocol;
setting an initial preference for the second consensus protocol to the highest accepted block;
transitioning to the second consensus protocol, wherein the second consensus protocol is run until a new accepted block is finalized, the new accepted block representing a successful protocol transition; and
broadcasting a complete message based on the new accepted block being finalized, wherein the node receiving the complete message triggers a reinstatement of the first protocol.

2. The computer-implemented method of claim 1 , further comprising reinstating the first consensus protocol after a consensus value of the new accepted block is finalized by running the second consensus protocol, wherein the first consensus protocol is reinstated on top of the new accepted block.

3. The computer-implemented method of claim 1 , wherein the first consensus protocol is a fast protocol that guarantees high safety, and the second consensus protocol is a protocol that guarantees high safety and high liveness.

4. The computer-implemented method of claim 1 , further comprising:
broadcasting, to the blockchain network, a preferred block of the set of nodes based on running the first consensus protocol, wherein the highest accepted block is determined based on the preferred block; and
waiting for a present number of broadcast messages comprising the preferred block from the set of nodes, wherein the initial preference for running the second consensus is set based on the preset number of broadcast messages being met.

5. The computer-implemented method of claim 1 , further comprising:
generating, based on the new accepted block, the complete message, wherein the complete message is tagged by an transition instance identification (ID); and
broadcasting the complete message to the blockchain network, wherein the node receiving the complete message triggers an instance counter to increment.

6. The computer-implemented method of claim 1 , further comprising monotonically incrementing a transition instance counter based on the second consensus protocol deciding on the new accepted block,
wherein the transition instance counter tracks each transition from the first consensus protocol to the second consensus protocol in the blockchain network as a transition instance, and a value of the transition instance counter represents a number of past accepted blocks as an identifier of the transition instance.

7. The computer-implemented method of claim 1 , wherein the second consensus protocol is a quorum-based asynchronous byzantine fault tolerance protocol.

8. The computer-implemented method of claim 1 , further comprising determining, based on the new accepted block, a staking set included in a shared chain block of the blockchain network using a height field included in the new accepted block, wherein the height field points to the shared chain block.

9. A system for implementing transition protocols, comprising:
a processor; and
a memory comprising instructions stored thereon, which when executed by the processor, causes the processor to:
run a first consensus protocol in a set of nodes of a blockchain network;
detect a liveness attack in the first consensus protocol at a node in the set of nodes;
initiate, based on detecting the liveness attack, a transition protocol enabling a transition from the first consensus protocol to a second consensus protocol;
suspend, when the liveness attack is detected, acceptance of new blocks in the first consensus protocol;
identify, based on a preferred block, a highest accepted block in the set of nodes from running the first consensus protocol;
set an initial preference for the second consensus protocol to the highest accepted block;
transition from the first consensus protocol to the second consensus protocol;
determine a consensus value of a new accepted block based on running the second consensus protocol in the set of nodes; and
broadcast a complete message based on the new accepted block being finalized, wherein the node receiving the complete message triggers a reinstatement of the first protocol, and the new accepted block represents a successful protocol transition.

10. The system of claim 9 , further comprising instructions, which when executed by the processor, cause the processor to:
reinstate the first consensus protocol after the consensus value of the new accepted block is determined, wherein the first consensus protocol is reinstated on top of the new accepted block.

11. The system of claim 9 , wherein the first consensus protocol is a fast protocol that guarantees high safety, and the second consensus protocol is a protocol that guarantees high safety and high liveness.

12. The system of claim 9 , further comprising instructions, which when executed by the processor, cause the processor to:
broadcast, to the blockchain network, the preferred block of the set of nodes based on running the first consensus protocol, wherein the highest accepted block is determined based on the preferred block; and
wait for a present number of broadcast messages comprising the preferred block from the set of nodes, wherein the initial preference for running the second consensus is set based on the preset number of broadcast messages being met.

13. The system of claim 9 , further comprising instructions, which when executed by the processor, cause the processor to:
generate, based on the new accepted block, a complete message including a transition instance identification (ID); and
broadcast the complete message to the blockchain network, wherein the broadcasting is inclusive of the node.

14. The system of claim 9 , further comprising instructions, which when executed by the processor, cause the processor to:
monotonically increment a transition instance counter based on the second consensus protocol deciding on the new accepted block, wherein the transition instance counter tracks each transition from the first consensus protocol to the second consensus protocol in the blockchain network, and a value of the transition instance counter represents a number of past accepted blocks as an identifier of the transition instance.

15. The system of claim 9 , wherein the second consensus protocol is a quorum-based asynchronous byzantine fault tolerance protocol.

16. A non-transitory computer-readable storage medium comprising instructions stored thereon, which when executed by one or more processors, cause the one or more processors to perform a method comprising:
running a first consensus protocol in a set of nodes of a blockchain network;
detecting a liveness attack in the first consensus protocol at a node in the set of nodes;
initiating, based on detecting the liveness attack, a transition protocol enabling a transition from the first consensus protocol to a second consensus protocol;
suspending, when the liveness attack is detected, acceptance of new blocks in the first consensus protocol;
identifying, based on a preferred bloc

Assignees

• Ava Labs Inc

Inventors

• Buttolph Stephen John
• Sekniqi Kevin

Classifications

• H04L63/1441 Primary

  Countermeasures against malicious traffic (countermeasures against attacks on cryptographic mechanisms H04L9/002) · CPC title

• H04L9/3239

  involving non-keyed hash functions, e.g. modification detection codes [MDCs], MD5, SHA or RIPEMD · CPC title

• H04L9/50 Primary

  using hash chains, e.g. blockchains or hash trees · CPC title