Online Courses
Blockchain Security
Online Courses
Blockchain Security
  • Blockchain Security
  • Fundamentals of Blockchain Security
    • Introduction to blockchain
    • The promises of blockchain
    • Inside the blockchain hype
    • Blockchain structures
    • What is public-key cryptography?
      • How does public-key cryptography work?
      • Public-key cryptography in the blockchain
    • Security assumptions of public-key cryptography
      • Quantum computing
    • Hash function in blockchain
      • Properties of hash functions
      • Hash functions in the blockchain
      • Blockchain security hash key functions
    • Quiz
  • Consensus Algorithm Security
    • Introduction
      • The Byzantine generals problem
      • Security via scarcity
      • Common blockchain consensus algorithms
      • The longest chain rule
    • Proof of work
      • Inside PoW mining
    • Attacking proof of work
      • The 51% attack
      • Denial of service: Artificial difficulty increases
    • Proof of stake
      • Choosing the block creator
    • Attacking PoS consensus
      • XX% attack and the PoS "timebomb"
      • Fake stake attacks
      • Long-range attack
      • Nothing at stake problem
      • Sour milk attack
    • Quiz
  • Blockchain in Action
    • Nodes and network
      • Inside the node
      • How blocks are created
    • Attacking block creation
      • Denial-of-service
      • Frontrunning
      • Selfish mining
      • SPV mining
    • Attacking blockchain nodes
      • Blockchain software misconfiguration
      • Denial of service
      • Malicious transactions
    • Attacking the blockchain network
      • Eclipse attack
      • Routing attack
      • Sybil attack
    • Quiz
  • Smart Contract Security
    • What are smart contracts?
      • Smart contracts
    • General programming vulnerabilities
      • Arithmetic vulnerabilities
      • Right-to-left control character
    • Blockchain vulnerabilities
    • Ethereum vulnerabilities
    • Quiz
  • Beyond the Basics
    • Alternative distributed ledger architectures
      • Introduction to DAGs
      • Introduction to block lattices
      • Introduction to sidechains
    • Second-level blockchain protocols
      • How a state channel works
    • Advanced cryptography in blockchain
      • Multisignatures
      • Zero-knowledge proofs
      • Stealth addresses
      • Ring signatures
      • Commitment schemes
    • Quiz
  • Cumulative Quiz
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  1. Consensus Algorithm Security
  2. Attacking PoS consensus

Nothing at stake problem

Blockchain is based upon incentivizing actors to behave correctly. More profitable to behave than misbehave

When presented with divergent chains, a PoS block creator has no incentive to only build their block on one of them. Longest chain rule means that the "accepted" one could potentially switch at any time

In fact, they're incentivized to build on any and all divergent chains. Creating a block carries a reward. If their chosen chain is beat out by another version, they lose their reward

Key points

  1. Blockchain is based on incentives: In Blockchain, there is no central authority that enforces ethical behavior. Instead, the system is designed to make it more profitable to do good things than to not do them.

  2. Block rewards: Miners or validators in the Blockchain ecosystem are rewarded for their efforts in creating blocks. It is more profitable to create legitimate blocks than fraudulent ones.

  3. The nothing at stake problem: In a proof of stake system, block creators may be presented with two different versions of the Blockchain. Without protection against the nothing at stake problem, they are incentivized to build on both chains to ensure they don't lose their block rewards.

  4. Misaligned incentives: The nothing at stake problem can lead to misaligned incentives. For example, if someone is performing a long-range attack, they may convince others to build on their malicious chain to avoid losing rewards on the legitimate chain.

  5. Protecting against the nothing at stake problem: Proof of stake systems can be designed to protect against the nothing at stake problem by implementing mechanisms to penalize those who engage in such behavior.

  6. Default behavior: By default, proof of stake systems have the issue of incentivizing participants to back every chain to ensure they receive their rewards.

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Last updated 9 months ago