Weakest Link

The strength of any chain is only as strong as its weakest link.

While a useful term in the industries that work with an actual chain¹, the analogy can also be expanded to composite (digital) systems with interdependent constituents.

graph LR
	classDef smallNode font-size:10px
	C0[Strong Link] --> C1[Weak Link] --> C2[Strong Link]

	C1:::smallNode

The argument then is that the overall Trustless-ness of a composite Authority is only as good as its weakest component.

Few examples of this concept that we see in this book:

• Oracle Problem, especially when bridging real-world information to the blockchain.
• Scaling Out - Pure Multi-chain, where an interconnected set of blockchains with different degrees of Economic Security exchanges value-bearing messages, and act upon them, not taking into account that the sending chain of a message might be compromised.

Footnotes

1. Originally appearing in “Essays on the Intellectual Powers of Man”. ↩