Midterm 01 - Technology: Hasing (SHA-256)

Fall 24

What is Hashing (SHA-256)?

an algorithm that scrambles data to produce a fixed length output.

Hashing Algorithm Properties

1. deterministic

2. collision resistance (unique)

3. pre-image resistance

4. secondary pre-image resistance

5. avalanche effect

Deterministic

Same input always produces same output

Collision resistance (unique)

Different inputs will not create same output

Pre-image resistance

Cannot infer or reverse engineer from hash back to original value

Secondary pre-image resistance

all guesses are worth the same - hackers cannot predict or create inputs better than random guessing.

Avalanche effect

any small change in the input will produce an unrecognizable output

What are the common uses of SHA-256 hashing?

create addresses:

• as input for digital signatures

• in blockchain for block identification (blockID)

• proof of work