Consensus Computing in CRE

Consensus computing is the foundational computing paradigm that makes CRE secure and reliable. It ensures that every operation your workflow performs—whether fetching data from an API or reading from a blockchain—is verified by multiple independent nodes before producing a final result.

What is consensus computing?

Consensus computing is when a decentralized network of nodes must form consensus as part of executing code and storing information. Unlike traditional computing where you trust a single server or service, consensus computing provides unique guarantees:

  • Tamper-resistance: No single node can manipulate results
  • High availability: The network continues operating even if individual nodes fail
  • Trust minimization: You don't need to trust any single entity
  • Verifiability: All results are cryptographically verified

Blockchains pioneered consensus computing for maintaining asset ledgers and executing smart contracts. CRE extends this paradigm to any offchain operation—API calls, computations, and more.

How CRE uses consensus

In CRE, every execution capability automatically includes decentralized consensus. Here's how it works:

  1. Independent execution: When your workflow invokes a capability (like http.Client or evm.Client), each node in the dedicated capability DON performs the operation independently
  2. Result collection: Each node produces its own result based on what it observed
  3. Consensus protocol: The DON applies a Byzantine Fault Tolerant (BFT) consensus protocol to validate and aggregate the individual results
  4. Verified output: A single, consensus-verified result is returned to your workflow

This process happens automatically for every capability call. You don't need to write any special code—consensus is built into the CRE runtime environment.

Why this matters for your workflows

Protection against node failures and manipulation

CRE's consensus model protects against individual node failures and malicious behavior. When multiple independent nodes execute the same operation:

  • Node-level resilience: If some nodes fail or go offline, the network continues operating
  • Byzantine Fault Tolerance: Even if some nodes are compromised and return incorrect results, the honest majority ensures the correct outcome
  • Execution consistency: All nodes must execute your workflow logic identically, preventing manipulation by individual operators

Validated and verified results

Every result your workflow receives has been cryptographically verified and validated across multiple nodes. This provides strong guarantees that:

  • The operation was executed correctly
  • The result matches what independent observers agreed upon
  • No single node operator can manipulate your workflow's execution or outputs

Unified security model

With CRE, your entire institutional-grade smart contract—not just the onchain parts—benefits from consensus computing. This means:

  • API responses are validated across multiple nodes before your workflow uses them
  • Blockchain reads are verified by multiple nodes
  • Blockchain writes are validated by multiple nodes before being submitted onchain
  • Computation results within your workflow are executed consistently across all nodes

Your workflow inherits the same security and reliability guarantees as blockchain transactions, but for any offchain operation.

Consensus in practice

HTTP capability

When your workflow makes an API request using http.Client, the HTTP capability DON executes your request across multiple nodes. Their responses are validated through a consensus protocol before returning a result to your workflow.

This ensures:

  • Execution consistency across all nodes
  • Protection against individual node compromise or failure
  • Detection of inconsistent API responses (e.g., due to load balancing or timing)

See the HTTP Capability page for details.

EVM Read & Write capability

When your workflow reads from or writes to a blockchain using evm.Client, the EVM capability DON performs the operation across multiple nodes:

  • For reads: Multiple nodes independently query the blockchain, and consensus validates their responses match
  • For writes: Multiple nodes agree on the transaction data before submitting it onchain

This ensures:

  • Execution consistency across all nodes
  • Protection against individual node compromise or failure
  • Validated blockchain data before use in your workflow

See the EVM Read & Write Capability page for details.

Consensus in simulation vs. deployed workflows

Learn more

Learn more about how to use CRE capabilities with built-in consensus:

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