SHA (Secure Hash Algorithm)

 SHA (Secure Hash Algorithm)


History of SHA family


SHA-0 (originally named just SHA) was a 160-bit hash function that was published in 1993 by National Institute of Standards and Technology (NIST) and withdrawn shortly because of a flaw. 

SHA-1 was also a 160-bit function that was replacement for SHA-0 (published in 1995 by NASA).

SHA-2 consists of two hash functions SHA-256 and SHA-512 (Developed by NASA in 2001 and 2004)

Main difference between the SHA algorithms are output string sizes.


How secure is SHA

Despite the fact that SHA-1 is no longer recommended for fell funded attackers, SHA-512 and SHA-256 are still very safe. Here is a video that explains how safe SHA-256 explains how long would it take to break SHA-256:

https://www.youtube.com/watch?v=S9JGmA5_unY


Why should you be interested in SHA-256?

SHA-256 is a really safe way to encrypt data and it is used by a lot of websites and banks, and even by the very famous bitcoin (more about bitcoin in my other post). But why would you care about it? Firstly SHA-256 is allowed for public use and you could use it to encrypt your own data or just read about it and educate yourself.


More about SHA-256 and it’s Characteristics?

SHA-256 is a hashing algorithm that takes an input that can vary from a single letter to thousands of words and turns it into a fixed 256 bit-sized string. And it’s usefulness comes from the fact that it is a ‘one way function’ meaning that there is no way to take the 256 bit-sized string and get the original input (currently the only way to get original input is to guess it and it takes a REALLY long time). And it also changes completely every time a single digit is changed, for example “A random sentence” has an output of “2f1a4a7877237bfca0cafa6a0e229de40aa924f4cb7035795b6095a1e91127e2”, while when you were to add a punctuation to end of it (“A random sentence.”), it would change to  “8c7b6b7feb64849815099a9b90b74f007f14254f644092123cc13d5b931c2dea”. But what makes it really useful is that it is deterministic, meaning it will always produce the same output, given the same input. So you can go to https://emn178.github.io/online-tools/sha256.html and get the same string from “A random sentence”.


Used articles:

https://komodoplatform.com/en/academy/sha-256-algorithm/

https://www.appviewx.com/education-center/encryption-standards-regulations-and-algorithms/what-is-sha-and-what-are-sha-1-and-sha-2/


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