Class: Encrypth::WebArchiver

Inherits:
Object
  • Object
show all
Defined in:
lib/encrypth/web_archiver.rb

Constant Summary collapse

SALT_LEN = 
32
IV_LEN = 
12
TAG_LEN = 
16

Instance Method Summary collapse

Constructor Details

#initialize(password) ⇒ WebArchiver

Returns a new instance of WebArchiver.



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# File 'lib/encrypth/web_archiver.rb', line 7

def initialize(password)
  @password = password
end

Instance Method Details

#decrypt(archive_path, destination) ⇒ Object 



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# File 'lib/encrypth/web_archiver.rb', line 46

def decrypt(archive_path, destination)
  File.open(archive_path, 'rb') do |file|
    salt = file.read(SALT_LEN)
    iv   = file.read(IV_LEN)
    
    ciphertext_len = File.size(archive_path) - SALT_LEN - IV_LEN - TAG_LEN
    key = derive_key(@password, salt)
    
    cipher = OpenSSL::Cipher.new('aes-256-gcm').decrypt
    cipher.key = key
    cipher.iv = iv
    
    ciphertext = file.read(ciphertext_len)
    auth_tag = file.read(TAG_LEN)
    cipher.auth_tag = auth_tag
    
    decrypted_data = cipher.update(ciphertext) + cipher.final
    
    tar_path = File.join(Dir.tmpdir, "dec_#{SecureRandom.hex(8)}.tar")
    File.binwrite(tar_path, decrypted_data)
    
    begin
      extract_tar(tar_path, destination)
    ensure
      File.delete(tar_path) if File.exist?(tar_path)
    end
  end
end

#encrypt(files) ⇒ Object 



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# File 'lib/encrypth/web_archiver.rb', line 11

def encrypt(files)
  out_path = File.join(Dir.tmpdir, "enc_#{SecureRandom.hex(8)}.tar.enc")
  tar_path = File.join(Dir.tmpdir, "tar_#{SecureRandom.hex(8)}.tar")
  
  salt = OpenSSL::Random.random_bytes(SALT_LEN)
  key = derive_key(@password, salt)
  
  begin
    create_tar(files, tar_path)
    
    cipher = OpenSSL::Cipher.new('aes-256-gcm').encrypt
    cipher.key = key
    iv = cipher.random_iv
    cipher.iv_len = IV_LEN
    cipher.iv = iv
    
    File.open(out_path, 'wb') do |out_f|
      out_f.write(salt)
      out_f.write(iv)
      
      File.open(tar_path, 'rb') do |tar_f|
        while chunk = tar_f.read(16384)
          out_f.write(cipher.update(chunk))
        end
      end
      out_f.write(cipher.final)
      out_f.write(cipher.auth_tag)
    end
    
    { path: out_path, size: File.size(out_path) }
  ensure
    File.delete(tar_path) if File.exist?(tar_path)
  end
end