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Questions about Cryptographic hash function

Short answers, pulled from the story.

What are the three main security requirements of a cryptographic hash function?

A cryptographic hash function must provide pre-image resistance, second pre-image resistance, and collision resistance. These properties ensure that malicious adversaries cannot replace or modify data without changing its digest.

When was MD5 designed by Ronald Rivest and what output size does it produce?

Ronald Rivest designed MD5 in 1991 to replace an earlier function called MD4. It produced a 128-bit digest and was specified as RFC 1321 in 1992.

Who developed SHA-3 and when did NIST publish it on the 5th of August 2015?

NIST published SHA-3 on the 5th of August 2015 which relies on the Keccak algorithm developed by Guido Bertoni, Joan Daemen, Michael Peeters, and Gilles Van Assche.

Why is MD5 considered unsuitable for most cryptographic uses after 2004?

Collisions against MD5 can be calculated within seconds rendering it unsuitable for most cryptographic uses. Researchers found collisions in several popular functions including MD5 and RIPEMD-128 in August 2004.

How do Bitcoin mining systems use hash functions to unlock rewards?

Bitcoin mining uses partial hash invocations to deter denial-of-service attacks and spam on networks. These mechanisms allow miners to find messages whose hash begins with specific zero bits to unlock rewards.

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