Sha-256

Definition

SHA-256 is a cryptographic hash function that produces a fixed-size 256-bit hash value from input data of any size. It's part of the SHA-2 family and is widely used in security applications and protocols, including SSL/TLS and cryptocurrency transactions, due to its strong resistance to collisions and pre-image attacks.

5 Must Know Facts For Your Next Test

1. SHA-256 generates a 64-character hexadecimal string, which represents the 256 bits of data produced by the hashing process.
2. It's widely used in Bitcoin mining to validate transactions and secure the network, as each block's header contains the SHA-256 hash of the previous block.
3. The algorithm is designed to be one-way, meaning it’s computationally infeasible to reverse-engineer the original input from its hash output.
4. SHA-256 is considered secure against known attack vectors, making it suitable for securing sensitive data and verifying digital signatures.
5. The performance of SHA-256 can vary based on hardware, with specialized hardware often being able to compute hashes significantly faster than standard processors.

Review Questions

• How does SHA-256 ensure data integrity in digital transactions?
  • SHA-256 ensures data integrity by generating a unique hash value for each input. When a transaction is initiated, it is hashed using SHA-256, producing a distinct 256-bit output. This hash acts as a digital fingerprint for the transaction. If any alteration occurs in the transaction data, even changing a single character, the SHA-256 hash will change significantly, indicating potential tampering.
• Evaluate the security features of SHA-256 compared to its predecessor, SHA-1.
  • SHA-256 offers enhanced security features compared to SHA-1 primarily due to its larger hash size of 256 bits versus SHA-1's 160 bits. This increased size makes it more resistant to collision attacks where two different inputs produce the same hash output. Additionally, vulnerabilities have been discovered in SHA-1, allowing for practical collision attacks, while SHA-256 remains robust against these threats, making it the preferred choice in modern cryptographic applications.
• Synthesize how SHA-256 contributes to the functionality and security of blockchain technology.
  • SHA-256 plays a critical role in blockchain technology by providing a secure hashing mechanism for linking blocks in a chain. Each block contains the SHA-256 hash of the previous block, ensuring that once data has been recorded on the blockchain, it cannot be altered without changing all subsequent blocks. This creates a secure and immutable ledger where each transaction can be verified through its unique hash. The algorithm also underpins mining processes in cryptocurrencies like Bitcoin, where miners compete to solve complex mathematical problems based on SHA-256 to add new blocks to the chain, ensuring both security and decentralization.

Related terms

Cryptographic Hash Function: A function that takes an input and produces a fixed-size string of characters, which is typically a digest that is unique to each unique input.

Collision Resistance: The property of a hash function that makes it difficult to find two different inputs that produce the same hash output.

Blockchain: A decentralized digital ledger that records transactions across many computers in a way that ensures the recorded transactions cannot be altered retroactively.