An SHA-3 implementation written in Crystal.

Supports:

• The FIPS 202 SHA-3 standard (Digest::SHA3)
• Keccak[3] (Digest::Keccak3)

The main difference between the two is the value of the first byte of padding set after the input in the buffer. For SHA-3, this byte is 6u8. For Keccak[3] it is 1u8.

Add the dependency to your shard.yml:

dependencies:
  sha3:
    github: OscarBarrett/crystal-sha3
    version: ~> 0.3

Then in your code:

require "sha3"

SHA-3

# Defaults to SHA3-512
Digest::SHA3.hexdigest("abc123")
# => 3274f8455be84b8c7d79f9bd93e6c8520d13f6bd2855f3bb9c006ca9f3cce25d4b924d0370f8af4e27a350fd2baeef58bc37e0f4e4a403fe64c98017fa012757

digest = Digest::SHA3.new(256)
digest.update("abc123")
digest.hexdigest
# => f58fa3df820114f56e1544354379820cff464c9c41cb3ca0ad0b0843c9bb67ee

Keccak3

# Defaults to a hash size of 512
Digest::Keccak3.hexdigest("abc123")
# => 17c4bf22aaa8fcd7ff070fd3435619b5666dc3eac901872c73f091d9f3753cd871161269f14741e3b263c616e9f4bb4314abcbb271b2796d14eb89434a0afd03

digest = Digest::Keccak3.new(256)
digest.update("abc123")
digest.hexdigest
# => 719accc61a9cc126830e5906f9d672d06eab6f8597287095a2c55a8b775e7016

Currently KAT specs are generated and not stored in this repository.

make spec
crystal spec

ExtremelyLongMsg KAT data for Keccak is included in the repo but is not tested.

LongMsg KAT data for SHA3 has not been located but should be added if a suitable source is found.

256,000 hashes:

Benchmarks can be run using make benchmark.

To compare with the Ruby sha3 gem (which uses a C binding), run:
make benchmark-compare
Ruby and bundler are required dependencies.