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Secure Hash Algorithms facts for kids

Kids Encyclopedia Facts

The Secure Hash Algorithms (often called SHA) are like special digital fingerprints for information. They are a group of cryptographic hash functions. Imagine you have a message or a file. A hash function takes that information and turns it into a short, unique code, like a fingerprint. This fingerprint is always the same length, no matter how big the original message is.

These algorithms were created and published by the National Institute of Standards and Technology (NIST) in the U.S.. They are used for important things like checking if a file has been changed or making sure digital signatures are real.

There are different versions of SHA algorithms:

  • SHA-0: This was the very first version, released in 1993. It was a 160-bit hash function. But soon after it came out, a problem was found with it. Because of this, it was quickly replaced by a slightly improved version called SHA-1.
  • SHA-1: This is also a 160-bit hash function. It was designed by the National Security Agency (NSA). SHA-1 was used as part of the Digital Signature Algorithm. However, experts later found some weaknesses in SHA-1. Because of these weaknesses, it is no longer recommended for most important security uses after 2010.
  • SHA-2: This is actually a family of several similar hash functions. The main ones are SHA-256 and SHA-512. They work a bit differently inside, especially with how they handle data. SHA-256 uses smaller pieces of data (32-bit words), while SHA-512 uses larger ones (64-bit words). There are also shorter versions like SHA-224, SHA-384, SHA-512/224, and SHA-512/256. These were also designed by the NSA.
  • SHA-3: This hash function was originally called Keccak. It was chosen in 2012 after a big public competition. Unlike the other SHA versions, SHA-3 was designed by people outside the NSA. It can create hash fingerprints of the same lengths as SHA-2. Its internal design is very different from the other SHA algorithms.

Checking SHA Algorithms

All SHA-family algorithms are considered important security tools. Because of this, they have to be officially checked and approved. This checking is done by the CMVP. The CMVP is a joint program run by the American National Institute of Standards and Technology (NIST) and the Canadian Communications Security Establishment (CSE). They make sure these algorithms work correctly and are secure.

See also

A robot thinking about digital security. In Spanish: Secure Hash Algorithm para niños

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