OpenSSL::Digest allows you to compute message digests (sometimes interchangeably called “hashes”) of arbitrary data that are cryptographically secure, i.e. a Digest implements a secure one-way function.
One-way functions offer some useful properties. E.g. given two distinct inputs the probability that both yield the same output is highly unlikely. Combined with the fact that every message digest algorithm has a fixed-length output of just a few bytes, digests are often used to create unique identifiers for arbitrary data. A common example is the creation of a unique id for binary documents that are stored in a database.
Another useful characteristic of one-way functions (and thus the name) is that given a digest there is no indication about the original data that produced it, i.e. the only way to identify the original input is to “brute-force” through every possible combination of inputs.
These characteristics make one-way functions also ideal companions for public key signature algorithms: instead of signing an entire document, first a hash of the document is produced with a considerably faster message digest algorithm and only the few bytes of its output need to be signed using the slower public key algorithm. To validate the integrity of a signed document, it suffices to re-compute the hash and verify that it is equal to that in the signature.
You can get a list of all digest algorithms supported on your system by running this command in your terminal:
openssl list -digest-algorithms
Among the OpenSSL 1.1.1 supported message digest algorithms are:
SHA224, SHA256, SHA384, SHA512, SHA512-224 and SHA512-256
SHA3-224, SHA3-256, SHA3-384 and SHA3-512
BLAKE2s256 and BLAKE2b512
Each of these algorithms can be instantiated using the name:
digest = OpenSSL::Digest.new('SHA256')
“Breaking” a message digest algorithm means defying its one-way function characteristics, i.e. producing a collision or finding a way to get to the original data by means that are more efficient than brute-forcing etc. Most of the supported digest algorithms can be considered broken in this sense, even the very popular MD5 and SHA1 algorithms. Should security be your highest concern, then you should probably rely on SHA224, SHA256, SHA384 or SHA512.
data = File.binread('document') sha256 = OpenSSL::Digest.new('SHA256') digest = sha256.digest(data)
data1 = File.binread('file1') data2 = File.binread('file2') data3 = File.binread('file3') sha256 = OpenSSL::Digest.new('SHA256') sha256 << data1 sha256 << data2 sha256 << data3 digest = sha256.digest
Digest instance data1 = File.binread('file1') sha256 = OpenSSL::Digest.new('SHA256') digest1 = sha256.digest(data1) data2 = File.binread('file2') sha256.reset digest2 = sha256.digest(data2)
Subclasses ‘BadAlias` for backwards compatibility
This class works in conjunction with Psych::Parser to build an in-memory parse tree that represents a YAML document.
parser = Psych::Parser.new Psych::TreeBuilder.new parser.parse('--- foo') tree = parser.handler.root
See Psych::Handler for documentation on the event methods used in this class.
Subclass of Zlib::Error. This error is raised when the zlib stream is currently in progress.
For example:
inflater = Zlib::Inflate.new inflater.inflate(compressed) do inflater.inflate(compressed) # Raises Zlib::InProgressError end
Zlib:Inflate is the class for decompressing compressed data. Unlike Zlib::Deflate, an instance of this class is not able to duplicate (clone, dup) itself.
Zlib::GzipWriter is a class for writing gzipped files. GzipWriter should be used with an instance of IO, or IO-like, object.
Following two example generate the same result.
Zlib::GzipWriter.open('hoge.gz') do |gz| gz.write 'jugemu jugemu gokou no surikire...' end File.open('hoge.gz', 'w') do |f| gz = Zlib::GzipWriter.new(f) gz.write 'jugemu jugemu gokou no surikire...' gz.close end
To make like gzip(1) does, run following:
orig = 'hoge.txt' Zlib::GzipWriter.open('hoge.gz') do |gz| gz.mtime = File.mtime(orig) gz.orig_name = orig gz.write IO.binread(orig) end
NOTE: Due to the limitation of Ruby’s finalizer, you must explicitly close GzipWriter objects by Zlib::GzipWriter#close etc. Otherwise, GzipWriter will be not able to write the gzip footer and will generate a broken gzip file.
Objects of class File::Stat encapsulate common status information for File objects. The information is recorded at the moment the File::Stat object is created; changes made to the file after that point will not be reflected. File::Stat objects are returned by IO#stat, File::stat, File#lstat, and File::lstat. Many of these methods return platform-specific values, and not all values are meaningful on all systems. See also Kernel#test.
exception to wait for reading by EWOULDBLOCK. see IO.select.
exception to wait for writing by EWOULDBLOCK. see IO.select.
The DidYouMean::Formatter is the basic, default formatter for the gem. The formatter responds to the message_for method and it returns a human readable string.
spell checker for a dictionary that has a tree structure, see doc/tree_spell_checker_api.md
Raised when the provided IP address is an invalid address.
Raised when the address is an invalid length.
This class is the base class for Net::HTTP request classes. The class should not be used directly; instead you should use its subclasses, listed below.
An request object may be created with either a URI or a string hostname:
require 'net/http' uri = URI('https://jsonplaceholder.typicode.com/') req = Net::HTTP::Get.new(uri) # => #<Net::HTTP::Get GET> req = Net::HTTP::Get.new(uri.hostname) # => #<Net::HTTP::Get GET>
And with any of the subclasses:
req = Net::HTTP::Head.new(uri) # => #<Net::HTTP::Head HEAD> req = Net::HTTP::Post.new(uri) # => #<Net::HTTP::Post POST> req = Net::HTTP::Put.new(uri) # => #<Net::HTTP::Put PUT> # ...
The new instance is suitable for use as the argument to Net::HTTP#request.
A new request object has these header fields by default:
req.to_hash # => {"accept-encoding"=>["gzip;q=1.0,deflate;q=0.6,identity;q=0.3"], "accept"=>["*/*"], "user-agent"=>["Ruby"], "host"=>["jsonplaceholder.typicode.com"]}
See:
You can add headers or override default headers:
# res = Net::HTTP::Get.new(uri, {'foo' => '0', 'bar' => '1'})
This class (and therefore its subclasses) also includes (indirectly) module Net::HTTPHeader, which gives access to its methods for setting headers.
Subclasses for HTTP requests:
Subclasses for WebDAV requests:
Parent class for informational (1xx) HTTP response classes.
An informational response indicates that the request was received and understood.
References:
Response class for Continue responses (status code 100).
A Continue response indicates that the server has received the request headers.
References:
Response class for Early Hints responses (status code 103).
The Early Hints indicates that the server has received and is processing the request, and contains certain headers; the final response is not available yet.
References:
Response class for Multi-Status (WebDAV) responses (status code 207).
The Multi-Status (WebDAV) response indicates that the server has received the request, and that the message body can contain a number of separate response codes.
References:
Response class for Found responses (status code 302).
The Found response indicates that the client should look at (browse to) another URL.
References:
Response class for Permanent Redirect responses (status code 308).
This and all future requests should be directed to the given URI.
References:
Response class for Bad Request responses (status code 400).
The server cannot or will not process the request due to an apparent client error.
References:
Response class for Unauthorized responses (status code 401).
Authentication is required, but either was not provided or failed.
References: