Avalanche’s Consensus Algorithm: The Key to High-Throughput Blockchain Applications (Part 1)

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Consensus is the process of getting a group of nodes to come to an agreement on a decision, and nodes can reach a consensus by following a set of steps called a consensus protocol. Avalanche is a novel consensus protocol that is scalable, robust, and decentralized, and it has low latency and high throughput.

Avalanche follows sub-sampling voting i.e. small randomly selected subsets of validators are asked to vote on whether a transaction should be accepted or rejected. This is followed by network gossip, where participants exchange information back and forth and continue to validate the transaction. 

The benefit of this consensus model is that consensus can be reached quickly, regardless of the number of nodes on the network. Compared to other blockchain networks like Bitcoin and Ethereum, Avalanche’s consensus model is more secure because it requires a higher percentage of network control to perform an attack. In Bitcoin, an attacker needs to control 51% of all computers to attack, while in Ethereum, an attacker needs to control 51% of all stake tokens. However, in Avalanche, an attacker needs to control up to 80% of the network to perform an attack, making it much more difficult to breach the network’s security. 

Avalanche can process up to 4,500 transactions per second per subnet. Each subnet is a new network within the Avalanche ecosystem and can have multiple blockchains with their own consensus models and virtual machines. This allows for greater flexibility in building blockchain applications.

Avalanche is not just one blockchain, but rather a network consisting of at least three different blockchains: 

  • X-Chain: It is used for creating, managing, and transferring tokens on the network. This blockchain is based on the DAG consensus model.
  • C-Chain: It is designed specifically for smart contracts. It is a copy of the Ethereum Virtual Machine (EVM), making it easy to use Ethereum dApps on Avalanche. 
  • P-Chain: It is responsible for managing subnets, coordinating all validator nodes, and handling the staking mechanism. 

In short, C-chain is for DeFi, X-chain is for transfers, and P-chain is for staking. 

The difference between Avalanche’s consensus protocol and the Snowman protocol is minimal: 

  • The Snowman protocol is a linearized version of Avalanche that is optimized for smart contracts and high throughput.  
  • The Snowman protocol is designed to meet the specific needs of the Ethereum Virtual Machine. 


DAG stands for Directed Acyclic Graphs. Here a new block can have multiple parents whereas  in Ethereum, a new block usually has only one parent.

Transactions in DAG are directly linked to each other in a partial order. This means that transactions can be processed partially without waiting for the next block. This also allows for multiple chains to exist, without any waste of resources. 

DAG uses a vertex, which is similar to a block in a linear blockchain. Each vertex contains the hashes of its parents and a list of transactions. This allows transactions to be batched and voted on in groups instead of one-by-one.  

A vertex is accepted only when all transactions within it are accepted. If a vertex contains a rejected transaction, then the entire vertex and its descendants are rejected. Any valid transaction is being reissued with a new vertex that is not a child of the rejected vertex. 

DAG follows causal ordering, which means it considers the causes and effects relationship between events, rather than the order in which they occur. This allows for more efficient processing of transactions and ensures the security of the network.

Avalanche Consists of Three Main Components:


Slush is a decision-making process where multiple consultations are held until a final decision is reached. However, this process can be vulnerable to malicious nodes that can keep the process going indefinitely. To address this issue, the next version, Slush Snowflake, was introduced.


Snowflake uses a counter system where a decision of “no” increments the counter. As soon as a “yes” decision is encountered, the counter is reset to zero and the process starts again. However, if a malicious network manages to overrule the vote at the end, by having one “yes” decision among nine “no” decisions, the counter will reset from nine to zero, causing delays in the transaction verification process. To address this issue, the next version, Snowball, was introduced.


In Snowball, the confidence level is compared. For example, if there are 9 “no” decisions and 1 “yes” decision, the confidence level is 9. This level is compared to the confidence level of any other decisions. If the confidence level of the other decision is lower, then the counter will not reset and will remain at 9. This ensures a more secure and efficient decision-making process.

In Conclusion,

Avalanche’s consensus algorithm is a groundbreaking innovation in the world of blockchain technology. Its unique approach to achieving consensus offers a number of advantages over traditional consensus algorithms, including improved speed, security, and scalability. By allowing nodes to independently determine the validity of transactions, Avalanche eliminates the need for costly and time-consuming mining processes, while also reducing the risk of centralization. With Avalanche, it’s now possible to achieve consensus on a global scale, enabling faster and more secure transactions than ever before. As blockchain technology continues to evolve, it’s clear that Avalanche is poised to play a major role in shaping the future of the industry.

So, are you excited to learn more about Avalanche? Then don’t miss out on the next part of our blog series! Where we’ll delve even deeper into the world of Avalanche and share some valuable insights that you don’t want to miss. So don’t forget to subscribe to our Digital Insider Newsletter and check out the next post.