Class: Kasefet::MasterKey

Inherits:
Object
  • Object
show all
Defined in:
lib/kasefet/master_key.rb

Constant Summary collapse

PBKDF2SaltLength = 
32
CipherKeyLength = 
32
CipherIVLength = 
12
CipherAuthTagLength = 
16

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(file, passphrase: nil, keyfile: nil) ⇒ MasterKey

Returns a new instance of MasterKey.



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# File 'lib/kasefet/master_key.rb', line 67

def initialize(file, passphrase: nil, keyfile: nil)
  @file = file

  # read in the key
  if File.exist?(@file)
    @key = File.binread(@file)
    if passphrase
      load_key_with_passphrase(passphrase)
    elsif keyfile
      load_key_with_keyfile(keyfile)
    end
  else
    # this is a new wallet, generate a random key
    cipher = OpenSSL::Cipher.new("aes-256-gcm")
    @key = cipher.random_key
    if passphrase
      store_key_with_passphrase(passphrase)
    elsif keyfile
      store_key_with_keyfile(keyfile)
    else
      File.binwrite(@file, @key)
    end
  end
end

Instance Attribute Details

#key ⇒ Object

Returns the value of attribute key.



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# File 'lib/kasefet/master_key.rb', line 92

def key
  @key
end

Instance Method Details

#load_key_with_keyfile(keyfile) ⇒ Object 



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# File 'lib/kasefet/master_key.rb', line 42

def load_key_with_keyfile(keyfile)
  master_key = File.binread(keyfile)
  cipher = OpenSSL::Cipher.new("aes-256-gcm")
  cipher.decrypt
  cipher.iv = @key[0...CipherIVLength]
  @key = @key[CipherIVLength..-1]
  cipher.auth_tag = @key[0...CipherAuthTagLength]
  @key = @key[CipherAuthTagLength..-1]
  cipher.key = master_key
  @key = cipher.update(@key) + cipher.final
end

#load_key_with_passphrase(passphrase) ⇒ Object 



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# File 'lib/kasefet/master_key.rb', line 54

def load_key_with_passphrase(passphrase)
  cipher = OpenSSL::Cipher.new("aes-256-gcm")
  cipher.decrypt
  salt = @key[0...PBKDF2SaltLength]
  @key = @key[PBKDF2SaltLength..-1]
  cipher.iv = @key[0...CipherIVLength]
  @key = @key[CipherIVLength..-1]
  cipher.auth_tag = @key[0...CipherAuthTagLength]
  @key = @key[CipherAuthTagLength..-1]
  cipher.key = passphrase_to_key(passphrase, salt)
  @key = cipher.update(@key) + cipher.final
end

#passphrase_to_key(passphrase, salt) ⇒ Object 



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# File 'lib/kasefet/master_key.rb', line 10

def passphrase_to_key(passphrase, salt)
  return OpenSSL::PKCS5.pbkdf2_hmac_sha1(passphrase, salt, 20000, CipherKeyLength)
end

#store_key_with_keyfile(keyfile) ⇒ Object 



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# File 'lib/kasefet/master_key.rb', line 29

def store_key_with_keyfile(keyfile)
  cipher = OpenSSL::Cipher.new("aes-256-gcm")
  master_key = File.binread(keyfile)
  cipher.encrypt
  cipher.iv = iv = cipher.random_iv
  cipher.key = master_key
  cipher.auth_data = ""
  encrypted_key = cipher.update(@key) + cipher.final
  encrypted_key = cipher.auth_tag + encrypted_key
  encrypted_key = iv + encrypted_key
  File.binwrite(@file, encrypted_key)
end

#store_key_with_passphrase(passphrase) ⇒ Object 



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# File 'lib/kasefet/master_key.rb', line 14

def store_key_with_passphrase(passphrase)
  cipher = OpenSSL::Cipher.new("aes-256-gcm")
  salt = SecureRandom.random_bytes(PBKDF2SaltLength)
  master_key = passphrase_to_key(passphrase, salt)
  cipher.encrypt
  cipher.iv = iv = cipher.random_iv
  cipher.key = master_key
  cipher.auth_data = ""
  encrypted_key = cipher.update(@key) + cipher.final
  encrypted_key = cipher.auth_tag + encrypted_key
  encrypted_key = iv + encrypted_key
  encrypted_key = salt + encrypted_key
  File.binwrite(@file, encrypted_key)
end