IOTHACK Logs

Transactions are hashed into a Merkle tree and only the root goes into the block header — so pruning old branches never changes the block's hash, letting nodes drop the data they no longer need. * Only the root hash sits in the block header; spent branches are stubbed off, so pr...

Quiz: IOTHACK / Bitcoin: A Peer-to-Peer Electronic Cash System | updated: Aug 01, 2026

Because SCM's real weak point is the physical-to-digital interface: if you can't trust the humans/sensors entering data, the blockchain can't fix it; and if you can trust them, a shared database already suffices. Run SCM through the methodology: it stores state, has multiple writ...

Quiz: IOTHACK / Do You Need a Blockchain? | updated: Jul 30, 2026

None is universally best — each is the right answer for some application, and the choice must be made deliberately from trust assumptions, the parties involved, and performance needs. The take-away is anti-hype but not anti-blockchain. The authors provide a structured methodology...

Quiz: IOTHACK / Do You Need a Blockchain? | updated: Jul 30, 2026

Public verifiability, transparency, privacy, integrity, redundancy, and the trust anchor. Property What it means Public verifiability Anyone can verify the state was updated per the protocol Transparency How much of the data/update process observers can see (not all-or-n...

Quiz: IOTHACK / Do You Need a Blockchain? | updated: Jul 30, 2026

Because currencies on Ripple (other than its own XRP) are "issued" by gateways that must be trusted to honour withdrawals — so Ripple shifts the correspondent-banking trust onto gateways rather than eliminating it. Ripple provides a shared settlement ledger and its native currenc...

Quiz: IOTHACK / Do You Need a Blockchain? | updated: Jul 30, 2026

Because e-voting's requirements pull against each other (anonymous votes vs public verifiability), and no proposed system has yet been shown to be simultaneously secure, verifiable, and private. E-voting genuinely matches the blockchain profile: many mutually distrusting parties,...

Quiz: IOTHACK / Do You Need a Blockchain? | updated: Jul 30, 2026

A factory is a contract that creates and manages other contracts. In Solidity you deploy a new contract instance from within a contract using the new keyword. import "./SimpleStorage.sol"; contract StorageFactory { SimpleStorage[] public simpleStorageArray; function cre...

Quiz: IOTHACK / Smart Contracts & the Remix IDE | updated: Jul 30, 2026

A library is a contract-like collection of reusable functions that holds no state and cannot receive ether. using Lib for Type attaches the library's functions to a type so you can call them as methods on values of that type. library PriceConverter { function getConversionRat...

Quiz: IOTHACK / Smart Contracts & the Remix IDE | updated: Jul 30, 2026

A child inherits a parent's functionality with contract Child is Parent. To replace a parent function, the parent function must be marked virtual and the child's version must be marked override. import "./SimpleStorage.sol"; contract ExtraStorage is SimpleStorage { //...

Quiz: IOTHACK / Smart Contracts & the Remix IDE | updated: Jul 30, 2026

Blockchains are deterministic — every node must reach the same result — so they cannot make API calls or read real-world data; different nodes would get different answers and consensus would break. A decentralized oracle network like Chainlink delivers that data on-chain instead....

Quiz: IOTHACK / Smart Contracts & the Remix IDE | updated: Jul 30, 2026