Crypt Helper

crypt_helper.rb

require 'rubygems'
require 'openssl'
require 'digest/sha2'
require 'base64'

class CryptHelper

  def self.generate_rsa_key(passphrase, bits = 4096)
    cipher = OpenSSL::Cipher::AES256.new(:CBC)
    rsa_key = OpenSSL::PKey::RSA.generate(bits)
    rsa_key.to_pem(cipher, passphrase)
  end

  def self.decrypt_rsa_key(encrypted_master_rsa_key_pem, passphrase)
    OpenSSL::PKey::RSA.new(encrypted_master_rsa_key_pem, passphrase)
  end

  def self.generate_iv64
    cipher = OpenSSL::Cipher::AES256.new(:CBC)
    Base64.strict_encode64(cipher.random_iv)
  end

  def self.encrypt64(string, pass, iv_b64)
    cipher = OpenSSL::Cipher::AES256.new(:CBC)
    cipher.encrypt
    cipher.key = Digest::SHA512.digest(pass)
    cipher.iv = Base64.strict_decode64(iv_b64)
    encrypted = cipher.update(string) + cipher.final
    Base64.strict_encode64(encrypted)
  end

  def self.decrypt64(string_b64, pass, iv_b64)
    cipher = OpenSSL::Cipher::AES256.new(:CBC)
    cipher.decrypt
    cipher.key = Digest::SHA512.digest(pass)
    cipher.iv = Base64.strict_decode64(iv_b64)
    cipher.update(Base64.strict_decode64(string_b64)) + cipher.final
  end

end