Glossary

Double Spend is a potential issue in digital currencies where the same tokens in a wallet are spent more than once. Blockchains use consensus mechanisms like Proof-of-Work or Proof-of-Stake to prevent double spending by requiring nodes to validate transactions before adding them to the ledger. This prevents users from spending the same tokens twice. Double spending can occur as a result of a 51% attack.

Gas price is a fee paid to validators for verifying transactions on blockchain networks like Ethereum. The term “Gas” is a measure of the computational work needed to process transactions and smart contracts on the network. Complex smart contracts need more gas to execute. Ethereum and Polygon use the term "gas fees," while the Bitcoin blockchain use "transaction fees" or “miner fees”. On Ethereum, gas fees are in Gwei, a unit of its cryptocurrency Ether.

A hard fork is a permanent divergence in a blockchain, resulting from an upgrade to the underlying protocol that creates new consensus rules. This can cause non-upgraded nodes to be unable to validate blocks created by upgraded nodes. “Hard forks” are different from “soft forks”, which are software upgrades that do not result in a chain split as long as the upgrade is adopted by the majority of nodes on the network. In a hard fork of a blockchain network, miners are divided on which protocol to adopt, resulting in a split and the creation of a new chain with a new set of protocols. Holders of the old chain's cryptocurrency are granted coins from the new forked chain.