CBCP Cryptography and Security Questions and Answers

Question 1

In public-key cryptography as used in blockchain, what is the primary function of the private key?

Accepted Answer

To encrypt the hash of a transaction, creating a digital signature.

Answer

To be shared publicly for verifying transactions.

Answer

To decrypt messages that were encrypted with the public key.

Answer

To generate a new public key for every transaction.

Question 2

A malicious actor gains control of a large number of nodes on a blockchain network by creating multiple fake identities. They then use this influence to isolate a genuine node from the rest of the network, feeding it false information. What type of attack is this?

Accepted Answer

Sybil Attack

Answer

Routing Attack

Answer

51% Attack

Answer

Phishing Attack

Question 3

Which cryptographic technique allows for computations to be performed on encrypted data without decrypting it first, offering enhanced privacy for smart contracts and blockchain analytics?

Accepted Answer

Homomorphic Encryption

Answer

Zero-Knowledge Proofs

Answer

Elliptic Curve Cryptography (ECC)

Answer

Multi-Party Computation (MPC)

Question 4

A user wants to prove they have a sufficient account balance to enter a decentralized lottery without revealing their actual balance or transaction history. Which cryptographic method is best suited for this scenario?

Accepted Answer

Zero-Knowledge Proof (ZKP)

Answer

Multi-signature Scheme

Answer

Symmetric Key Encryption

Answer

Digital Signature Algorithm (DSA)

Question 5

Compared to the RSA algorithm, what is the primary advantage of using Elliptic Curve Cryptography (ECC) for generating key pairs in blockchain systems like Bitcoin and Ethereum?

Accepted Answer

It provides the same level of security with significantly smaller key sizes.

Answer

It is resistant to attacks from quantum computers.

Answer

The decryption process is mathematically simpler and faster.

Answer

It uses a single key for both encryption and decryption.

Question 6

A developer is building a decentralized application and needs to store user private keys. Which of the following represents the MOST secure storage practice?

Accepted Answer

Storing keys offline in a hardware wallet and requiring user interaction for signing.

Answer

Storing the encrypted private key in the browser's local storage.

Answer

Sending the private key to a secure, centralized company server for management.

Answer

Writing the private key directly into the application's source code.