SHA-3 (Keccak) extension for Ruby
C Ruby Makefile
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The SHA-3 (Keccak) extension for Ruby

This Ruby extension implements the SHA-3 (Keccak) cryptographic hashing algorithm. It is based on the reference C implementation, version 3.2. The exposed interface is almost identical to that of the digest standard library.


gem install digest-sha3

Note: as of version 1.1.0, digest-sha3 requires Ruby 2.2. The last version that worked on older versions was 1.0.2.


Keccak supports 5 hash lengths: 224-bit, 256-bit, 384-bit, 512-bit and variable length. Variable length is not supported by this Ruby extension. Unless the user specifies otherwise, this Ruby extension assumes 512-bit.

require 'digest/sha3'

# Generate 512-bit digest.
Digest::SHA3.digest("foo")       # => "\025\227\204*..."
Digest::SHA3.hexdigest("foo")    # => "1597842a..."

# Generate 224-bit digest.
Digest::SHA3.digest("foo", 224)       # => "\332\251M\247..."
Digest::SHA3.hexdigest("foo", 224)    # => "daa94da7..."

# Use this interface to feed data in chunks. 512-bit by default.
digest =
digest.digest       # => "\025\227\204*..."
digest.hexdigest    # => "1597842a..."

# You can pass a hash length to the constructor.
digest =

Running the test suite

Run the test suite as follows:

make test

A part of the test suite is automatically generated from Keccak's reference test suite.


Do not use SHA-3 for hashing passwords. Do not even use SHA-3 + salt for hashing passowords. Use a slow hash instead.

See also