Question 1

What is a cryptographic hash function?

Accepted Answer

A cryptographic hash function transforms input data into a fixed-length output called a hash. It is designed to be difficult to reverse and highly resistant to collisions, making it useful for data integrity, blockchain links, transaction IDs, password protection, and Merkle trees .

Question 2

How does hashing secure a blockchain?

Accepted Answer

Blockchain systems use hashes to connect blocks, summarize transactions, verify data, and support consensus. If someone changes a transaction or block, the resulting hash changes, alerting network participants that the data no longer matches the validated blockchain history.

Question 3

What is the difference between hashing and encryption?

Accepted Answer

Hashing is normally a one-way process used to create a verifiable data fingerprint. Encryption converts readable information into protected ciphertext that can be decrypted with an appropriate key. In blockchain systems, hashing primarily supports integrity, while encryption helps protect confidential information.

Question 4

Which cryptographic algorithms are used in blockchain technology?

Accepted Answer

Common examples include SHA-256, Keccak-256, SHA-3, ECDSA, EdDSA, Schnorr signatures, Scrypt, and Argon2 . The exact algorithm depends on the blockchain platform, its consensus mechanism, wallet design, privacy requirements, and security objectives.

Question 5

Can quantum computers break blockchain cryptography?

Accepted Answer

Large-scale quantum computers could threaten some current public-key cryptographic systems, particularly those based on elliptic curve mathematics. Blockchain researchers are investigating post-quantum cryptography, quantum-resistant signatures, and migration strategies to protect future decentralized networks.

Hashing & Cryptographic Algorithms