Module: Digest
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Defined in: | ext/digest/digest.c, ext/digest/bubblebabble/bubblebabble.c, ext/digest/lib/digest.rb, ext/digest/md5/md5init.c, ext/digest/rmd160/rmd160init.c, ext/digest/sha1/sha1init.c |
Overview
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 web.mit.edu/kenta/www/one/bubblebabble/spec/jrtrjwzi/draft-huima-01.txt.
Digest algorithms
Different digest algorithms (or hash functions) are available:
- HMAC
-
See FIPS PUB 198 The Keyed-Hash Message Authentication Code (HMAC).
- RIPEMD-160
-
As Digest::RMD160. See homes.esat.kuleuven.be/~bosselae/ripemd160.html.
- SHA1
-
See FIPS 180 Secure Hash Standard.
- SHA2 family
-
See FIPS 180 Secure Hash Standard which defines the following algorithms:
-
SHA512
-
SHA384
-
SHA256
-
The latest versions of the FIPS publications can be found here: csrc.nist.gov/publications/PubsFIPS.html.
Constant Summary
-
REQUIRE_MUTEX =
A mutex for Digest().
Mutex.new
Class Method Summary
-
.bubblebabble(string) ⇒ bubblebabble_string
mod_func
Returns a BubbleBabble encoded version of a given string.
-
.hexencode(string) ⇒ hexencoded_string
mod_func
Generates a hex-encoded version of a given string.
Class Method Details
.bubblebabble(string) ⇒ bubblebabble_string
(mod_func)
Returns a BubbleBabble encoded version of a given string.
.hexencode(string) ⇒ hexencoded_string
(mod_func)
Generates a hex-encoded version of a given string.