This README is better viewed through the YARD formatted documentation: rdoc.info/github/ueno/ruby-gpgme/frames for latest github version, or rdoc.info/gems/gpgme for latest gem release.
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Ruby 1.8 or later
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GPGME 1.1.2 or later
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gpg-agent (optional, but recommended)
$ gem install gpgme
GPGME provides three levels of API. The highest level API is as simple as it gets, the mid level API provides more functionality but might be less user-friendly, and the lowest level API is close to the C interface of GPGME.
For example, to create a cleartext signature of the plaintext from stdin and write the result to stdout can be written as follows.
crypto = GPGME::Crypto.new crypto.clearsign $stdin, :output => $stdout
The same example can be rewritten in the mid level API as follows.
plain = GPGME::Data.new($stdin) sig = GPGME::Data.new($stdout) GPGME::Ctx.new do |ctx| ctx.sign(plain, sig, GPGME::SIG_MODE_CLEAR) end
The same example can be rewritten in the lowest level API as follows.
ret = [] GPGME::gpgme_new(ret) ctx = ret.shift GPGME::gpgme_data_new_from_fd(ret, 0) plain = ret.shift GPGME::gpgme_data_new_from_fd(ret, 1) sig = ret.shift GPGME::gpgme_op_sign(ctx, plain, sig, GPGME::SIG_MODE_CLEAR)
As you see, it’s much harder to write a program in this API than the highest level API. However, if you are already familiar with the C interface of GPGME and want to control detailed behavior of GPGME, it might be useful.
All the high level methods attack the mid level GPGME::Ctx API. It is recommended to read through the GPGME::Ctx.new methods for common options.
Also, most of the input/output is done via GPGME::Data objects that create a common interface for reading/writing to normal strings, or other common objects like files. Read the GPGME::Data documentation to understand how it works. Every time the lib needs a GPGME::Data object, it will be automatically converted to it.
The GPGME::Crypto class has the high level convenience methods to encrypt, decrypt, sign and verify signatures. Here are some examples, but it is recommended to read through the GPGME::Crypto class to see all the options.
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Document encryption via
GPGME::Crypto#encrypt:
crypto = GPGME::Crypto.new crypto.encrypt "Hello world!", :recipients => "someone@example.com"
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Symmetric encryption:
crypto = GPGME::Crypto.new :password => "gpgme" crypto.encrypt "Hello world!", :symmetric => true
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Document decryption via
GPGME::Crypto#decrypt(including signature verification):
crypto.decrypt File.open("text.gpg")
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Document signing via
GPGME::Crypto#sign. Also the clearsigning and detached signing.
crypto.sign "I hereby proclaim Github the beneficiary of all my money when I die"
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Sign verification via
GPGME::Crypto#verify
sign = crypto.sign "Some text" data = crypto.verify(sign) { |signature| signature.valid? }
The GPGME::Key object represents a key, and has the high level related methods to work with them and find them, export, import, deletetion and creation.
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Key listing
GPGME::Key.find(:secret, "someone@example.com") # => Returns an array with all the secret keys available in the keychain. # that match "someone@example.com"
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Key exporting
GPGME::Key.export("someone@example.com") # => Returns a GPGME::Data object with the exported key. key = GPGME::Key.find(:secret, "someone@example.com").first key.export # => Returns a GPGME::Data object with the exported key.
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Key importing
GPGME::Key.import(File.open("my.key"))
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Key validation
GPGME::Key.valid?(public_key) # => Returns wheter this key is valid or not
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TODO: Key generation
Provides three convenience methods to obtain information about the gpg engine one is currently using. For example:
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Getting current information
GPGME::Engine.info.first
# => #<GPGME::EngineInfo:0x00000100d4fbd8
@file_name="/usr/local/bin/gpg",
@protocol=0,
@req_version="1.3.0",
@version="1.4.11">
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Changing home directory to work with different settings:
GPGME::Engine.home_dir = '/tmp'
Rather than importing the keys it’s possible to specify the recipient when performing crypto functions. Here’s a roundtrip example, and note that as this is for a console, the conf.echo = false line is to stop IRB complaining when echoing binary data
# Stop IRB echoing everything, which errors with binary data. # Not required for production code conf.echo = false class PassphraseCallback def initialize(passphrase) @passphrase = passphrase end def call(*args) fd = args.last io = IO.for_fd(fd, 'w') io.puts(@passphrase) io.flush end end # recipients can be found using $ gpg --list-keys --homedir ./keychain_location # pub 2048R/A1B2C3D4 2014-01-17 # Use that line to substitute your own. 2048R is the key length and type (RSA in this case) # If you want to substitute a non-default keychain into the engine do this: # home_dir = Rails.root.join('keychain_location').to_s # GPGME::Engine.set_info(GPGME::PROTOCOL_OpenPGP, '/usr/local/bin/gpg', home_dir) # Note GPG executable location will change across platforms crypto = GPGME::Crypto.new options = {:recipients => 'A1B2C3D4'} plaintext = GPGME::Data.new(File.open(Rails.root.join('Gemfile'))) data = crypto.encrypt plaintext, options f = File.open(Rails.root.join('Gemfile.gpg'), 'wb') bytes_written = f.write(data) f.close puts bytes_written crypto = GPGME::Crypto.new options = {:recipients => 'A1B2C3D4', :passphrase_callback => PassphraseCallback.new('my_passphrase')} cipthertext = GPGME::Data.new(File.open(Rails.root.join('Gemfile.gpg'))) data = crypto.decrypt cipthertext, options puts data
To run the local test suite you need bundler and gpg:
bundle rake compile # simple rake task to compile the extension rake # runs the test suite
The library itself is licensed under LGPLv2.1+. See the file COPYING.LESSER and each file for copyright and warranty information.