Class: MasterCrypt

Inherits:
Object
  • Object
show all
Defined in:
lib/master_crypt.rb,
lib/master_crypt/version.rb

Defined Under Namespace

Classes: CryptoError

Constant Summary collapse

VERSION = 
"0.0.5"

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(master_key) ⇒ MasterCrypt

Create a new MasterCrypt object with a master key which is used in ‘master_key_encrypt` and `master_key_decrypt`

Parameters:

  • Master (String) —

    key

Raises:

  • (ArgumentError) 


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# File 'lib/master_crypt.rb', line 15

def initialize(master_key)
  raise ArgumentError, "Master key must not be blank" if master_key.nil? || master_key.empty?
  @master_key = master_key
end

Class Method Details

.decrypt(encrypted_data, secret_key) ⇒ String

Decrypts encrypted data with a provided secret key

Parameters:

  • encrypted_data (String) —

    Base64 representation of encrypted data

  • secret_key (String) —

    Secret key to be used to decrypt data

Returns:

  • (String) —

    Decrypted plaintext data

Raises:



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# File 'lib/master_crypt.rb', line 88

def decrypt(encrypted_data, secret_key)
  encrypted_data64, encrypted_random_keys64_joined = Base64.strict_decode64(encrypted_data).split("|", 2)

  encrypted_random_keys64 = encrypted_random_keys64_joined.split(":")
  key = find_key(encrypted_random_keys64, secret_key)

  box = RbNaCl::SimpleBox.from_secret_key(key)

  ciphertext = Base64.strict_decode64(encrypted_data64)
  box.decrypt(ciphertext).force_encoding(Encoding::UTF_8)
rescue RbNaCl::CryptoError => e
  raise CryptoError, e.message
end

.encrypt(plaintext, secret_keys) ⇒ String

Encrypts plaintext data with a list of secret keys

Parameters:

  • plaintext (String) —

    Plaintext data to be encrypted

  • secret_keys (Array<String>) —

    A list of secret keys to be used for encrypting data

Returns:

  • (String) —

    Base64 representation of encrypted data

Raises:

  • (ArgumentError) —

    When secret keys are missing or blank



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# File 'lib/master_crypt.rb', line 54

def encrypt(plaintext, secret_keys)
  raise ArgumentError, "At least 1 secret key is required" if !secret_keys.is_a?(Array) || secret_keys.empty?
  raise ArgumentError, "Secret keys must not be blank" unless secret_keys.select(&:empty?).empty?
  # there's no point in using the same key multiple times
  secret_keys.uniq!

  random_key = RbNaCl::Random.random_bytes(RbNaCl::SecretBox.key_bytes)
  # encrypt data with random_key
  box = RbNaCl::SimpleBox.from_secret_key(random_key)

  encrypted_data = box.encrypt(plaintext)
  encrypted_data64 = Base64.strict_encode64(encrypted_data)

  # encrypt random_kets with each secret
  encrypted_random_keys64 = secret_keys.collect do |secret|
    key = generate_key_from_secret(secret)
    box = RbNaCl::SimpleBox.from_secret_key(key)

    encrypted_random_key = box.encrypt(random_key)
    encrypted_random_key64 = Base64.strict_encode64(encrypted_random_key)
    encrypted_random_key64
  end
  # encrypted_data|encrypted_random_key1:encrypted_random_key2:...
  Base64.strict_encode64(encrypted_data64 + "|" + encrypted_random_keys64.join(":"))
end

Instance Method Details

#master_key_decrypt(encrypted_data) ⇒ String

Decrypts encrypted data with the master key

Parameters:

  • encrypted_data (String) —

    Base64 representation of encrypted data

Returns:

  • (String) —

    Decrypted plaintext data

Raises:



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# File 'lib/master_crypt.rb', line 41

def master_key_decrypt(encrypted_data)
  self.class.decrypt(encrypted_data, @master_key)
end

#master_key_encrypt(plaintext, secret_keys = []) ⇒ String

Encrypts plaintext data with the master key and an optional list of additional secret keys

additional secret keys to be used for encrypting data

Parameters:

  • plaintext (String) —

    Plaintext data to be encrypted

  • secret_keys (Array<String>) (defaults to: []) —

    Optional list of

Returns:

  • (String) —

    Base64 representation of encrypted data

Raises:

  • (ArgumentError) —

    When secret keys are missing or blank



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# File 'lib/master_crypt.rb', line 30

def master_key_encrypt(plaintext, secret_keys = [])
  self.class.encrypt(plaintext, [@master_key] + Array(secret_keys))
end