- published: 28 Sep 2016
- views: 1242
SHA-2 (Secure Hash Algorithm 2) is a set of cryptographic hash functions designed by the NSA. SHA stands for Secure Hash Algorithm. Cryptographic hash functions are mathematical operations run on digital data; by comparing the computed "hash" (the output from execution of the algorithm) to a known and expected hash value, a person can determine the data's integrity. For example, computing the hash of a downloaded file and comparing the result to a previously published hash result can show whether the download has been modified or tampered with. A key aspect of cryptographic hash functions is their collision resistance: nobody should be able to find two different input values that result in the same hash output.
SHA-2 includes significant changes from its predecessor, SHA-1. The SHA-2 family consists of six hash functions with digests (hash values) that are 224, 256, 384 or 512 bits: SHA-224, SHA-256, SHA-384, SHA-512, SHA-512/224, SHA-512/256.
SHA-256 and SHA-512 are novel hash functions computed with 32-bit and 64-bit words, respectively. They use different shift amounts and additive constants, but their structures are otherwise virtually identical, differing only in the number of rounds. SHA-224 and SHA-384 are simply truncated versions of the first two, computed with different initial values. SHA-512/224 and SHA-512/256 are also truncated versions of SHA-512, but the initial values are generated using the method described in FIPS PUB 180-4. SHA-2 was published in 2001 by the NIST as a U.S. federal standard (FIPS). The SHA-2 family of algorithms are patented in US patent 6829355. The United States has released the patent under a royalty-free license.
You're already seeing SHA-1 hash warnings. You've basically got 2-14 months to get migrated, depending on your applications. Attend this session and learn everything about SHA-1 to SHA-2 migrations, including the following:_x000D_\n Why do we have to migrate, what really is the threat?_x000D_\n When do we have to migrate? What applications don't like SHA-1? What applications don't like SHA-2?_x000D_\n How to migrate Active Directory Certificate Services (ADCS) to SHA-2_x000D_\n A SHA-1 to SHA-2 migration plan_x000D_\n_x000D_\nFrequent presenter and Microsoft Principal Security Architect, Roger A. Grimes, will teach you how to talk to your customers about SHA-2 and how to get them there. https://ignite.microsoft.com/
Here is a detailed walkthrough of why the strength of the hash function used to sign the certificates is very important and why SHA-1 is being phased out in favour of SHA-2. We go through the end to end process of signing a certificate, then in reverse show what happens as the signatures are validated by the browser. Then we discuss some ways in which a compromise of the hash functions can lead to dangerous scenarios on the internet. Finally a brief overview of what people who are responsible for websites need to know and the urgency of making the changes. If you're looking for a great text description of how the SSL chain works I would recommend this one. http://commandlinefanatic.com/cgi-bin/showarticle.cgi?article=art012
The tutorial is at: http://www.asecuritysite.com/Encryption/md5
Bitcoins are mined using a cryptographic algorithm called SHA-256. This algorithm is simple enough to be done with pencil and paper, as I show in this video. Not surprisingly, this is a thoroughly impractical way to mine. One round of the algorithm takes 16 minutes, 45 seconds which works out to a hash rate of 0.67 hashes per day. For details, see http://righto.com/sha
For clearer illustrations, a .ppsx file (ppt slide show with narration) can be accessed at https://www.dropbox.com/s/j7k4c5nm3zgezp2/ppsxABU_SHA2_Presentation.ppsx
Audible free book: http://www.audible.com/computerphile Hashing Algorithms are used to ensure file authenticity, but how secure are they and why do they keep changing? Tom Scott hashes it out. More from Tom Scott: http://www.youtube.com/user/enyay and https://twitter.com/tomscott http://www.facebook.com/computerphile https://twitter.com/computer_phile This video was filmed and edited by Sean Riley. Pigeon Sound Effects courtesy of http://www.freesfx.co.uk/ Computerphile is a sister project to Brady Haran's Numberphile. See the full list of Brady's video projects at: http://bit.ly/bradychannels
Entrust navigates you through the rapid sun-setting of SHA-1 certificates for a seamless, secure experience for your end users.
https://github.com/openssl/openssl/blob/master/crypto/sha/sha256.c https://github.com/B-Con/crypto-algorithms/blob/master/sha256.c Details: https://drive.google.com/file/d/0B4-Ln6UubyEeS3NmdVJOODNmZzA/
SSL certificates are used to encrypt traffic between two devices, proving that your site is what it says it is, and that it’s safe. About 90% of sites use SSL encryption, and you see it as the ‘https’ bit in your browser’s address bar; it might also have a padlock symbol or turn the address bar green. As part of SSL you have ‘SHA’, which is the algorithm used to generate the certificate. Until recently most sites have been using SHA-1, but it’s not really safe any more, so lots of experts want to upgrade to SHA-2, which is much stronger and supported nearly everywhere. The people behind our browsers have plans to move everything over to SHA-2, but it might take years. Google has decided to take the lead though, and is pushing for it to happen sooner. As we get closer to 2015, warning s...
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What exactly did he do to make you cry this time
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I will comfort, comfort, comfort you
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Lay down and tell me what's on your mind
What exactly did he do to make you cry this time
Well, I will be your comforter, I will make it right