CBSE - Certified Blockchain Security Expert Blockchain Cryptography Fundamentals Questions and Answers 1 — Questions and Answers
Question 1: Which of the following cryptographic primitives is primarily used in blockchain to ensure data integrity and create a unique, fixed-size fingerprint of transaction data?
- Symmetric Encryption
- Asymmetric Encryption
- Cryptographic Hash Functions (Correct answer)
- Digital Signatures
Correct answer: Cryptographic Hash Functions
Cryptographic hash functions are fundamental to blockchain technology for ensuring data integrity. They take an input of any size and produce a fixed-size output (a hash). Any change to the input data results in a completely different hash, making it easy to detect tampering. This property is crucial for linking blocks together in a chain and for creating Merkle trees.
Question 2: A blockchain development team is choosing a public-key cryptography algorithm for their new platform. They require high security with smaller key sizes to optimize for speed and reduce storage demands. Which algorithm best meets these requirements?
- RSA (Rivest-Shamir-Adleman)
- AES (Advanced Encryption Standard)
- ECC (Elliptic Curve Cryptography) (Correct answer)
- SHA-256
Correct answer: ECC (Elliptic Curve Cryptography)
Elliptic Curve Cryptography (ECC) provides the same level of security as other algorithms like RSA but with significantly smaller key sizes. This efficiency reduces computational overhead and storage requirements, making it ideal for resource-constrained environments and blockchain applications where performance is critical.
Question 3: In a blockchain transaction, what is the primary purpose of a digital signature?
- To encrypt the transaction data for confidentiality.
- To ensure the transaction can be reversed if incorrect.
- To provide proof of the sender's identity (authentication) and guarantee the message has not been altered (non-repudiation and integrity). (Correct answer)
- To reduce the size of the transaction data for faster processing.
Correct answer: To provide proof of the sender's identity (authentication) and guarantee the message has not been altered (non-repudiation and integrity).
A digital signature in a blockchain transaction cryptographically proves that the transaction was authorized by the holder of the private key (authentication), ensures the transaction data has not been tampered with (integrity), and prevents the sender from later denying they sent the transaction (non-repudiation).
Question 4: A user sends a cryptocurrency transaction. The transaction is combined with several others into a block. Which data structure is used to efficiently and securely verify that this specific transaction is included in the block without needing to download and check every single transaction?
- Linked List
- Merkle Tree (Correct answer)
- Binary Search Tree
- Hash Table
Correct answer: Merkle Tree
A Merkle Tree, or hash tree, is a data structure where each leaf node is a hash of a transaction. These hashes are then paired and hashed together until a single root hash, the Merkle Root, is created. This root hash summarizes all transactions in the block. To verify a transaction's inclusion, one only needs the transaction's hash and the path of hashes leading to the root, which is far more efficient than processing the entire block's transaction list.
Question 5: What is the key difference between cryptographic hashing and encryption in the context of blockchain security?
- Encryption is a one-way function, while hashing is a two-way function.
- Hashing is used for data confidentiality, while encryption is used for data integrity.
- Hashing is a reversible process, while encryption is irreversible.
- Hashing is a one-way function primarily for data integrity, while encryption is a two-way function for data confidentiality. (Correct answer)
Correct answer: Hashing is a one-way function primarily for data integrity, while encryption is a two-way function for data confidentiality.
The fundamental difference is reversibility and purpose. Hashing is a one-way, irreversible function that converts data into a unique digest to verify integrity. Encryption is a two-way, reversible process that converts plaintext to ciphertext and back again using a key, with the primary goal of ensuring data confidentiality.
Question 6: A security auditor is reviewing a blockchain's cryptographic implementation. They note that the system uses a private key to create a digital signature and a corresponding public key to verify it. This model is an example of which type of cryptography?
- Symmetric Cryptography
- Hash-based Cryptography
- Secret Key Cryptography
- Asymmetric Cryptography (Correct answer)
Correct answer: Asymmetric Cryptography
Asymmetric cryptography, also known as public-key cryptography, uses a pair of keys: a private key that is kept secret and a public key that can be shared. Data signed with the private key can be verified by anyone with the public key. This is the foundation for digital signatures in blockchain, which authenticate transactions.
CBSE - Certified Blockchain Security Expert Blockchain Cryptography Fundamentals Questions and Answers 1
Which of the following cryptographic primitives is primarily used in blockchain to ensure data integrity and create a unique, fixed-size fingerprint of transaction data?