Sentry lib - painless encryption library

Sentry is a simple wrapper around the mostly undocumented OpenSSL encryption classes.

For now, look at the pseudo test cases in sentry.rb until I can get more examples written out.

Resources

Install

• gem install sentry

Rubyforge project

• rubyforge.org/projects/sentry

RDocs

• sentry.rubyforge.org

Subversion

• techno-weenie.net/svn/projects/sentry

Collaboa

• collaboa.techno-weenie.net/repository/browse/sentry

Using with ActiveRecord

I wrote this for the purpose of encrypting ActiveRecord attributes. Just require 'sentry', and some new class methods will be available to you:

generates_crypted

generates_crypted :password, :mode => :sha | :symmetric | :asymmetric

This is the generic class method to use. Default mode is :sha.

generates_crypted_hash_of

generates_crypted_hash_of :password

This is a shortcut for using SHA encryption. No different than specifying generates_crypted :password. In the above example, model.password is a virtual field, and the SHA hash is saved to model.crypted_password

asymmetrically_encrypts

asymmetrically_encrypts :password

This is a shortcut for using an asymmetrical algorithm with a private/public key file. To use this, generate a public and private key with Sentry::AsymmetricalSentry.save_random_rsa_key(private_key_file, public_key_file). If you want to encrypt the private key file with a symmetrical algorithm, pass a secret key (neither the key nor the decrypted value will be stored).

Sentry::AsymmetricSentry.save_random_rsa_key(private_key_file, public_key_file, :key => 'secret_password')

What that does, is requires you to pass in that same secret password when accesing the method.

class Model < ActiveRecord::Base
  generates_crypted :password, :mode => :asymmetric
end

model.password = '5234523453425'
model.save   # password is encrypted and saved to crypted_password in the database, 
             # model.password is cleared and becomes a virtual field.
model.password('secret_password')
=> '5234523453425'

The public and private key file names can be set in config/environment.rb

Sentry::AsymmetricSentry.default_public_key_file = "#{RAILS_ROOT}/config/public.key"
Sentry::AsymmetricSentry.default_private_key_file = "#{RAILS_ROOT}/config/private.key"

If the private key was encrypted with the Sentry::AsymmetricalSentry#save_random_rsa_key, you must provide that same key when accessing the AR model.

symmetrically_encrypts

symmetrically_encrypts :password

This is a shortcut for using a symmetrical algorithm with a secret password to encrypt the field.

class Model < ActiveRecord::Base
  generates_crypted :password, :mode => :symmetric
end

model.password = '5234523453425'
model.save   # password is encrypted and saved to crypted_password in the database, 
             # model.password is cleared and becomes a virtual field.
model.password
=> '5234523453425'

The secret password can be set in config/environment.rb

Sentry::SymmetricSentry.default_key = "secret_password"