CBSE Study Guide 2026
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📋 CBSE Exam Format at a Glance
📚 CBSE Topics to Study (69)
✍️ Sample CBSE Questions & Answers
1. A developer deploys a contract that reads price data from a Chainlink oracle but does not check the 'updatedAt' timestamp. What vulnerability does this create?
Without validating that the oracle's updatedAt timestamp is recent, the contract may act on stale prices during network outages or oracle failures, enabling attackers to profit from the discrepancy.
2. What does 'transaction malleability' allow an attacker to do at the network level before a transaction is confirmed?
Transaction malleability lets a third party tweak the scriptSig data, producing a different txid for the same economic transaction, which can confuse tracking systems.
3. In a blockchain security audit, which property is verified by 'liveness testing'?
Liveness testing confirms that the blockchain system continues to make progress and process valid transactions under normal and adverse conditions.
4. In a threshold signature scheme (t-of-n), what happens cryptographically if fewer than t key shares attempt to reconstruct the private key?
In Shamir's Secret Sharing (the basis of most threshold schemes), fewer than t shares reveal zero information about the secret due to the polynomial construction used.
5. What is the primary security vulnerability associated with paper wallets?
Paper wallets exist only as physical objects; if lost, stolen, burned, or deteriorated, the private key is permanently irrecoverable with no backup mechanism.
6. What is the primary purpose of a blockchain node's mempool (memory pool) from a security perspective?
The mempool temporarily holds unconfirmed transactions; attackers can exploit it via transaction pinning or fee manipulation to delay or block legitimate transactions.