Digest

This module provides a framework for message digest libraries.

You may want to look at OpenSSL::Digest as it supports more algorithms.

A cryptographic hash function is a procedure that takes data and returns a fixed bit string: the hash value, also known as digest. Hash functions are also called one-way functions, it is easy to compute a digest from a message, but it is infeasible to generate a message from a digest.

Examples

require 'digest'
# Compute a complete digest
Digest ::SHA256.digest 'message' #=> "\xABS\n\x13\xE4Y..."
sha256 = Digest ::SHA256.new
sha256.digest 'message' #=> "\xABS\n\x13\xE4Y..."
# Other encoding formats
Digest ::SHA256.hexdigest 'message' #=> "ab530a13e459..."
Digest ::SHA256.base64digest 'message' #=> "q1MKE+RZFJgr..."
# Compute digest by chunks
md5 = Digest ::MD5 .new
md5.update 'message1'
md5 << 'message2' # << is an alias for update
md5.hexdigest #=> "94af09c09bb9..."
# Compute digest for a file
sha256 = Digest ::SHA256.file 'testfile'
sha256.hexdigest

Additionally digests can be encoded in "bubble babble" format as a sequence of consonants and vowels which is more recognizable and comparable than a hexadecimal digest.

require 'digest/bubblebabble'
Digest ::SHA256.bubblebabble  'message' #=> "xopoh-fedac-fenyh-..."

See the bubble babble specification at http://web.mit.edu/kenta/www/one/bubblebabble/spec/jrtrjwzi/draft-huima-01.txt.

Digest algorithms

Different digest algorithms (or hash functions) are available:

The latest versions of the FIPS publications can be found here: http://csrc.nist.gov/publications/PubsFIPS.html.

Related methods