Flash loans in Blockchain / Solidity - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a flash loan in blockchain?

A flash loan is a type of uncollateralized loan that must be borrowed and repaid within a single blockchain transaction.

beginner

Why do flash loans not require collateral?

Because the loan is repaid within the same transaction, the blockchain ensures the lender either gets the money back or the whole transaction fails, so no collateral is needed.

beginner

What happens if a flash loan is not repaid in the same transaction?

The entire transaction is reverted, meaning all actions are undone and the loan is never given out.

intermediate

Give a simple example use case of a flash loan.

A trader can borrow funds to quickly buy an asset, sell it at a higher price, repay the loan, and keep the profit, all within one transaction.

intermediate

What is a key risk associated with flash loans?

Flash loans can be used for attacks like price manipulation or exploiting vulnerabilities in smart contracts.

What ensures a flash loan is safe for the lender?

A The borrower provides collateral

B The loan must be repaid within the same transaction

C The loan is insured by a third party

D The loan is given only to trusted users

Flash loans require repayment within the same transaction, or the transaction fails, protecting the lender.

Which of these is NOT a characteristic of a flash loan?

A Loan duration can be several days

B No collateral required

C Repaid within one transaction

D Used for arbitrage or quick trades

Flash loans must be repaid within the same transaction, so they cannot last several days.

What happens if a flash loan is not repaid on time?

A The transaction is reverted

B The lender loses money

C The borrower is blacklisted

D The loan is converted to a regular loan

If the flash loan is not repaid in the same transaction, the entire transaction is reverted.

Flash loans are mostly used for:

A Long-term investments

B Buying real estate

C Quick arbitrage opportunities

D Paying salaries

Flash loans are used for quick trades like arbitrage within one transaction.

Which is a potential risk of flash loans?

A They require high collateral

B They are only available to banks

C They have long repayment periods

D They can be used to exploit smart contract bugs

Flash loans can be used maliciously to exploit vulnerabilities in smart contracts.

Explain how a flash loan works in a blockchain transaction.

Think about what happens if the loan is not paid back immediately.

Describe one practical use case and one risk of flash loans.

Consider both benefits and dangers of instant loans.