Class: BlueDoc::License::Encryptor

Inherits:
Object
  • Object
show all
Defined in:
lib/bluedoc/license/encryptor.rb

Defined Under Namespace

Classes: DecryptionError, Error, KeyError

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(key) ⇒ Encryptor

Returns a new instance of Encryptor.



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# File 'lib/bluedoc/license/encryptor.rb', line 12

def initialize(key)
  if key && !key.is_a?(OpenSSL::PKey::RSA)
    raise KeyError, "No RSA encryption key provided."
  end

  @key = key
end

Instance Attribute Details

#key ⇒ Object

Returns the value of attribute key.



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# File 'lib/bluedoc/license/encryptor.rb', line 10

def key
  @key
end

Instance Method Details

#decrypt(data) ⇒ Object 



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# File 'lib/bluedoc/license/encryptor.rb', line 20

def decrypt(data)
  unless key.public?
    raise KeyError, "Provided key is not a public key."
  end

  json_data = Base64.decode64(data.chomp)

  begin
    encryption_data = JSON.parse(json_data)
  rescue JSON::ParserError
    raise DecryptionError, "Encryption data is invalid JSON."
  end

  unless %w(data key iv).all? { |key| encryption_data[key] }
    raise DecryptionError, "Required field missing from encryption data."
  end

  encrypted_data  = Base64.decode64(encryption_data["data"])
  encrypted_key   = Base64.decode64(encryption_data["key"])
  aes_iv          = Base64.decode64(encryption_data["iv"])

  begin
    # Decrypt the AES key using asymmetric RSA encryption.
    aes_key = self.key.public_decrypt(encrypted_key)
  rescue OpenSSL::PKey::RSAError
    raise DecryptionError, "AES encryption key could not be decrypted."
  end

  # Decrypt the data using symmetric AES encryption.
  cipher = OpenSSL::Cipher::AES128.new(:CBC)
  cipher.decrypt

  begin
    cipher.key = aes_key
  rescue OpenSSL::Cipher::CipherError
    raise DecryptionError, "AES encryption key is invalid."
  end

  begin
    cipher.iv = aes_iv
  rescue OpenSSL::Cipher::CipherError
    raise DecryptionError, "AES IV is invalid."
  end

  begin
    data = cipher.update(encrypted_data) + cipher.final
  rescue OpenSSL::Cipher::CipherError
    raise DecryptionError, "Data could not be decrypted."
  end

  data
end