35 lines
1.4 KiB
Markdown
35 lines
1.4 KiB
Markdown
# SHAmwow
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Sometimes you just want to understand how your hashing algorithms work, so you implement them yourself.
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It should go without saying that this was just for fun, and you should never, ever, _ever_ roll your own cryptography primatives for any purpose other than education!
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## sha1
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The sha1 function in `shamwow.rb` implements the SHA1 hashing function in Ruby, outputting the 160-bit hash as a hexadecimal string.
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### sources
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* wikipedia's pseudocode breakdown: <https://en.wikipedia.org/wiki/SHA-1#Examples_and_pseudocode>
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## sha2
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The sha2 function in `shamwow.rb` implements the SHA-256 hashing function in Ruby, outputting the 256-bit hash as a hexadecimal string.
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### Sources
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* the actual spec: <http://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.180-4.pdf>
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* wikipedia's pseudocode breakdown: <https://en.wikipedia.org/wiki/SHA-2#Pseudocode>
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* a JS implementation that helped as I was debugging some boneheaded mistakes: <http://www.movable-type.co.uk/scripts/sha256.html>
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* slides of a talk explaining the steps <https://speakerd.s3.amazonaws.com/presentations/c7c8df2206074d83b3d18fcba3287328/slides.pdf>
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## Tests
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`shamwow_test.rb` contains a few sanity tests for the bit-rotation functions and for the hashes themselves, testing against the output of the `Digest` gem in the standard library.
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## Obligatory
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[](https://www.youtube.com/watch?v=F3lrhPeK6gU)
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