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M3)ZK-SNARK in 6 Simple Points
Proves something is true without showing the secret. You can prove you know information without revealing the information itself.
Proof is very small and fast to verify. Even big or complex statements create tiny, quick proofs.
No back-and-forth communication is needed. The prover sends one single proof, and the verifier checks it.
Uses a trusted setup at the beginning. Public parameters are created once; everyone uses them.
Keeps data private while still proving correctness. Used for private transactions where amounts and addresses stay hidden.
Widely used in blockchains like Zcash for privacy and scalability. Helps verify large computations on-chain without revealing sensitive data.
M3) 3 security properties of HASH function?
1.Preimage Resistance (One-way property)
You cannot find the original data from the hash.
Hash → data is almost impossible.
2. Second Preimage Resistance
If you know one input and its hash,
you cannot find another different input with the same hash.
3. Collision Resistance
You cannot find any two different inputs that produce the same hash.
No two messages should have identical hashes.
M4) Explain the structure and life cycle of a bitcoin transaction?
###Structure of a Bitcoin Transaction:
#Metadata
This includes basic details like transaction size, number of inputs and outputs, version, lock time, and the transaction ID.
#Inputs
Inputs are old UTXOs you already own. They act as the source of funds. You sign them with your private key #Outputs:
This includes the receiver’s address and the amount. These outputs become new UTXOs that can be spent later.
###Lifecycle of a Bitcoin Transaction:
#Creation
Your wallet creates a transaction, chooses inputs, sets outputs, and signs it.
#Broadcasting
The transaction is sent to many nodes in the network.
#Verification by nodes
Nodes check if the inputs are valid, unspent, correctly signed, and properly formatted.
#Mempool :
Verified transactions sit in the mempool until miners add them into a block.
#Miner selection
Miners pick transactions from the mempool, usually choosing higher-fee ones first.
#Proof of Work
Miners solve a difficult puzzle to create a valid block.
#Block broadcast
The new block is shared with the rest of the network, and other nodes verify it.
#Confirmations
Once your transaction is inside a block, it has 1 confirmation.
#Finalization
After enough confirmations, the transaction is permanent and cannot be reversed.
M4)Smart Contracts — discuss their history, evolution, and the advantages they offer over traditional contracts.?
###History of Smart Contracts
Nick Szabo proposed smart contracts in the 1990s as code that runs agreements automatically. Bitcoin (2009) allowed simple smart contract features but was limited. Ethereum (2015) made smart contracts powerful and popular with its programming language. Early projects like The DAO showed both potential and security risks.
###Evolution
Started with basic Bitcoin scripts. Became advanced with Ethereum and Solidity. New languages and templates were created for safer and more structured contracts. Security methods improved to avoid bugs and hacks
##advantages :
They work automatically when conditions are met. No middlemen are needed. They cannot be changed once on the blockchain.
Everyone can see how they work. They execute very fast. They reduce cheating and mistakes. They save money.
M4)Explain the process of deploying a smart contract on a public blockchain?
1. Write the smart contract code.
2. Compile the code into bytecode.
3. Create a deployment transaction containing the compiled code.
4. Sign the transaction with your private key.
5. Broadcast the signed transaction to the blockchain network.
6. Nodes check it, and miners add it into a block.
7. The blockchain gives the contract a unique address.
8. Users can now interact with the contract by sending transactions to that address.
M4)Genesis Block — describe its significance in maintaining the security and continuity of the blockchain.?
It is the very first block of the blockchain and acts as the starting point for everything. Its hash is linked to all future blocks, making it an anchor for the whole chain. If anyone tries to change old data, the chain breaks, so it helps keep the blockchain tamper-proof. Its details are fixed in the blockchain software, so everyone agrees on the same starting point. Creating the Genesis Block marks the official launch of the blockchain.
M4)Importance of Smart Contract Templates and their role in simplifying smart contract development.?
Templates give ready-made structures, so developers don’t need to write every contract from scratch.
They help connect legal terms with code, making smart contracts more accurate for legal and financial use.
Well-tested templates reduce mistakes and security bugs.
They improve compatibility so contracts can work across different blockchains. Templates allow quick customization for things like insurance, trading, or energy deals. They include industry standards, helping developers follow best practices and legal rules
M4)Ricardian Contracts — compare and contrast Ricardian Contracts and Smart Contracts.?
###Ricardian Contracts:
They are legal documents that both humans and computers can read. They contain clear legal language plus digital signatures. Their main goal is to be legally binding and enforceable in court. They focus on legal meaning, not automatic execution. They look like detailed documents connected to code.
###Smart Contracts:
They are computer programs that run automatically on a blockchain. They execute rules and actions without human involvement. Their main goal is automation and self-enforcement. They focus on code execution, not legal text.
M4) Illustrate how an oracle interacts with a smart contract using a diagram?
Step 1: The smart contract initiates a data request for an off-chain event or data point.
Step 2: The oracle fetches the data from an external source.
Step 3: The oracle uses an attestation service, such as TLSNotary or trusted hardware, to generate a proof of data authenticity.
Step 4: The oracle sends the data with its proof back to the smart contract.
Step 5: The smart contract verifies the proof and, upon confirmation, uses the data to trigger subsequent business logic.
M5)Contract creation transaction and message call transaction — explain with a suitable diagram.?
###Contract Creation Transaction:
– Its primary function is to deploy a new smart contract on the Ethereum blockchain.
– Essential parameters include the sender’s address, gas, gas price, initial Ether allocation (endowment), and the initialization code for the contract.
– Upon execution, if successful, a new account with a unique contract address is created, containing the deployed code and balance.
###Message Call Transaction:
– Used to interact with existing contracts or transfer Ether without creating a new contract.
– Parameters include sender, recipient, gas, value, input data (call data), etc.
– It results in a state change if the call executes successfully but does not create a new account.
m5)Explain the architecture and functioning of the Ethereum Virtual Machine (EVM). Why is the EVM considered a critical component of Ethereum?
The Ethereum Virtual Machine (EVM) is the engine that runs all smart contracts on Ethereum. It is like a computer inside every Ethereum node that executes the same code in the same way, ensuring trust and consistency.
###EVM Architecture:
Uses a stack to run instructions.
Works with 256-bit data. Has code , memory , and storage . Uses gas for every operation. Errors revert everything. Runs in a sandbox with no external access.
###How the EVM Works
It reads the contract’s bytecode when a transaction calls it.
It executes instructions one by one using stack, memory, and storage. It uses transaction details like sender, value, gas, and input data. If everything runs fine, the state is updated . If something fails, all changes are undone. It returns output data or logs after execution.
###Why the EVM Is Important :
It runs all smart contracts on Ethereum.
Ensures every node gets the same result.
Keeps execution safe using isolation.
Makes Ethereum programmable for dApps.
Supports DeFi, NFTs, DAOs, and many more applications.
M5)Role of Ether and Gas in executing smart contracts.?
🔹 Role of Ether (ETH) –
Ether is the currency of Ethereum. It is used to pay for Gas, which is needed to run transactions and smart contracts. Miners earn Ether as a reward for processing transactions. Every contract execution needs enough Ether to cover gas fees.
🔹 Role of Gas –
Gas measures how much work a transaction or smart contract needs. Every EVM instruction has a fixed gas cost. Gas prevents infinite loops and misuse by charging for computation. Users set gasLimit and gasPrice to decide cost and speed. Total fee = gasUsed × gasPrice. Unused gas is refunded, but if gas runs out, execution fails and changes are reverted.
M5)The consensus mechanism used by Ethereum — compare Ethereum’s Proof of Work (PoW) and Proof of Stake (PoS).?
🔹 Proof of Work (PoW) –
Miners solve puzzles using powerful computers. The first to solve the puzzle creates the next block. Uses a lot of electricity and expensive hardware. Security comes from the huge amount of computing power needed to attack the network.
🔹 Proof of Stake (PoS) –
No puzzles. Validators are chosen to create blocks based on how much Ether they stake . Uses very little energy. If validators cheat, their stake can be slashed . Rewards are given for validating correctly.
M5)Ethereum in detail — discuss its architecture, key features, and how it differs from Bitcoin.?
###Ethereum :
Ethereum is a blockchain platform that runs smart contracts and DApps.
It uses the EVM to execute code, gas to pay for computation, and Ether (ETH) as its currency.
It is decentralized, secure, and programmable.
##Key Features
Runs smart contracts
Uses PoW earlier, now moving to PoS
Supports DApps, DeFi, NFTs, DAOs
Faster and more flexible than Bitcoin
###Ethereum vs Bitcoin
Ethereum: Smart contracts + applications
Bitcoin: Digital money only
Ethereum is faster, programmable, and more flexible.
m5)What is Geth? Explain how Geth is used for managing Ethereum clients and wallets. Describe some common Geth commands.?
Geth (Go Ethereum) is a command–
Line Ethereum client used to run an Ethereum node, manage wallets, and interact with the blockchain. It is one of the most widely used Ethereum clients.
###How Geth Manages Clients & Wallets
#Run a node:
Using geth, you connect to Ethereum and sync the blockchain.
#JavaScript console:
geth attach opens a console where you can manage accounts, send transactions, and interact with smart contracts.
#Wallet management
You can create, list, unlock, and use Ethereum accounts. Keys are stored securely in the keystore.
#Syncing with the network:
Geth downloads all blocks and keeps the node updated with the latest state.
###commands:
geth
geth attach
personal.NewAccount(“password”)
eth.Accounts
eth.GetBalance(a)
M5) Explain the process of mining in Ethereum and its consensus model.?
###Ethereum Mining :
Mining means verifying transactions and adding blocks using Proof of Work. Miners try different nonces until they find a valid hash. Ethereum uses Ethash and the DAG file to keep mining decentralized. Miners earn block rewards, gas fees, and Uncle rewards.
###Consensus :
Ethereum uses the GHOST protocol, choosing the heaviest chain . Uncles are included to improve fairness and security. Ethereum is shifting from PoW → PoS (Casper) to reduce energy use.