Changes

Algorithms such as MD5<ref>https://blog.avira.com/md5-the-broken-algorithm/</ref><ref>http://cryptocrats.com/crypto/md5-the-hash-algorithm-is-now-broken/</ref> and SHA-1<ref>https://www.thesslstore.com/blog/sha-1-collision-created/</ref> have been "broken" by producing collisions.

Algorithms such as MD5<ref>https://blog.avira.com/md5-the-broken-algorithm/</ref><ref>http://cryptocrats.com/crypto/md5-the-hash-algorithm-is-now-broken/</ref> and SHA-1<ref>https://www.thesslstore.com/blog/sha-1-collision-created/</ref> have been "broken" by producing collisions.

== MD5 ==

=== MD5 ===

MD5 became a computing standard <ref>http://tools.ietf.org/html/rfc1321</ref> for hashing but was subsequently found to be insecure<ref>http://merlot.usc.edu/csac-f06/papers/Wang05a.pdf</ref> and was replaced with SHA1. MD5 breaks the input up into 512-bit blocks and churns it down into a 128-bit bit hash. For example, the text "The quick brown fox jumps over the lazy dog" would become (base64 encoded):

MD5 became a computing standard <ref>http://tools.ietf.org/html/rfc1321</ref> for hashing but was subsequently found to be insecure<ref>http://merlot.usc.edu/csac-f06/papers/Wang05a.pdf</ref> and was replaced with SHA1. MD5 breaks the input up into 512-bit blocks and churns it down into a 128-bit bit hash. For example, the text "The quick brown fox jumps over the lazy dog" would become (base64 encoded):

<code>50842ef1bd9a95a284b395a0f0e0e2f8</code><br />

<code>50842ef1bd9a95a284b395a0f0e0e2f8</code><br />

MD5 was intended to solve a weakness in MD4, although both were actually published as open standards at the same time. For this reason, MD4 was never largely implemented and MD5 became the algorithm of choice.

MD5 was intended to solve a weakness in MD4, although both were actually published as open standards at the same time. For this reason, MD4 was never largely implemented and MD5 became the algorithm of choice.

== RIPEMD ==

=== RIPEMD ===

RIPEMD (Race Integrity Primitives Evaluation Message Digest)<ref>"RIPEMD." TheFreeDictionary.com. 2019. Farlex, Inc. 15 May. 2019 https://acronyms.thefreedictionary.com/RIPEMD</ref> was released in 1992, and based on MD4. This original RIPEMD-128 ran two instances of the MD4 algorithm in parallel. It was therefore less efficient than MD5, and not entirely trusted by many, since MD4 had a weakness which had been known since its public release. A hash collision was found with PIREMD in 2004, and the industry stopped using it.  However, RIPEMD-160 (the most popular), RIPEMD-256, are RIPEMD-320 are strengthened (utilizing larger keys) versions of this algorithm which were released in 1996 and are still in use today.  

RIPEMD (Race Integrity Primitives Evaluation Message Digest)<ref>"RIPEMD." TheFreeDictionary.com. 2019. Farlex, Inc. 15 May. 2019 https://acronyms.thefreedictionary.com/RIPEMD</ref> was released in 1992, and based on MD4. This original RIPEMD-128 ran two instances of the MD4 algorithm in parallel. It was therefore less efficient than MD5, and not entirely trusted by many, since MD4 had a weakness which had been known since its public release. A hash collision was found with PIREMD in 2004, and the industry stopped using it.  However, RIPEMD-160 (the most popular), RIPEMD-256, are RIPEMD-320 are strengthened (utilizing larger keys) versions of this algorithm which were released in 1996 and are still in use today.  

== SHA-1 ==

=== SHA-1 ===

SHA (Secure Hash Algorithm) is a set of functions for hashing which fixed the problems found in MD5 and has since become the industry standard. SHA1 hashes down to a 160-bit hash. For example, the text "The quick brown fox jumps over the lazy dog" would become (base64 encoded):

SHA (Secure Hash Algorithm) is a set of functions for hashing which fixed the problems found in MD5 and has since become the industry standard. SHA1 hashes down to a 160-bit hash. For example, the text "The quick brown fox jumps over the lazy dog" would become (base64 encoded):

<code>

<code>

SHA-1 has been found not to have sufficient complexity to reduce collisions, so it is now disfavored.

SHA-1 has been found not to have sufficient complexity to reduce collisions, so it is now disfavored.

== SHA-2==

=== SHA-2===

SHA-2 (typically SHA-256) is an updated version of SHA-1, which adds complexity to help reduce the chance of hash collisions.

SHA-2 (typically SHA-256) is an updated version of SHA-1, which adds complexity to help reduce the chance of hash collisions.

"SHA-224," "SHA-384," and "SHA-512" are also forms of SHA-2, which are using other key lengths; the trailing number states the key length in use.  The greater the key size, the more difficult it is to have a hash collision, as this produces a longer hash. For example, the text "The quick brown fox jumps over the lazy dog" using SHA-256 would produce:

"SHA-224," "SHA-384," and "SHA-512" are also forms of SHA-2, which are using other key lengths; the trailing number states the key length in use.  The greater the key size, the more difficult it is to have a hash collision, as this produces a longer hash. For example, the text "The quick brown fox jumps over the lazy dog" using SHA-256 would produce: