What is the Byzantine Generals Problem?

What is the Byzantine Generals Problem?

• The Byzantine Generals Problem was introduced in 1982 to describe the challenge of achieving consensus in distributed systems. It imagines a group of generals (nodes) surrounding a city who must coordinate to either “attack” or “retreat,” despite the possibility of traitors or unreliable communication.

• Each general must decide: attack or retreat. Once a decision is made, it cannot be changed, and the decision must be consistent across all generals to succeed.

• The core challenge is that messages may be delayed, lost, or tampered with, and traitors may deliberately spread false information. The system must still ensure that all loyal generals reach the same decision.

• In blockchain, this represents the problem of how decentralized nodes reach consensus on valid blocks, even when some participants act maliciously. Byzantine Fault Tolerance (BFT) algorithms are designed to solve this issue.