Class: EncryptAttr::Encryptor

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

Constant Summary collapse

CIPHER = 
"AES-256-CBC".freeze

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(secret_token) ⇒ Encryptor

Returns a new instance of Encryptor.



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# File 'lib/encrypt_attr/encryptor.rb', line 26

def initialize(secret_token)
  @secret_token = secret_token
end

Instance Attribute Details

#secret_token ⇒ Object (readonly)

Set the encryptor’s secret token.



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# File 'lib/encrypt_attr/encryptor.rb', line 24

def secret_token
  @secret_token
end

Class Method Details

.decrypt(secret_token, value) ⇒ Object 



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# File 'lib/encrypt_attr/encryptor.rb', line 19

def self.decrypt(secret_token, value)
  new(secret_token).decrypt(value)
end

.encrypt(secret_token, value) ⇒ Object 



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# File 'lib/encrypt_attr/encryptor.rb', line 15

def self.encrypt(secret_token, value)
  new(secret_token).encrypt(value)
end

.validate_secret_token(secret_token) ⇒ Object 



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# File 'lib/encrypt_attr/encryptor.rb', line 5

def self.validate_secret_token(secret_token)
  return unless secret_token.size < 100

  offending_line = caller
                    .reject {|entry| entry.include?(__dir__) || entry.include?("forwardable.rb") }
                    .first[/^(.*?:\d+)/, 1]

  warn "[encrypt_attribute] secret token must have at least 100 characters (called from #{offending_line})"
end

Instance Method Details

#decode(value) ⇒ Object 



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# File 'lib/encrypt_attr/encryptor.rb', line 65

def decode(value)
  Base64.decode64(value)
end

#decrypt(value) ⇒ Object 



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# File 'lib/encrypt_attr/encryptor.rb', line 41

def decrypt(value)
  cipher = OpenSSL::Cipher.new(CIPHER).decrypt
  key = Digest::SHA256.digest(secret_token)

  parts = value.split(";")

  if parts.size == 1
    value = decode(value)
    iv = key[0...cipher.iv_len]
  else
    iv = parts.first
    value = decode(parts.last)
  end

  cipher.key = key
  cipher.iv = iv

  cipher.update(value) + cipher.final
end

#encode(value) ⇒ Object 



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# File 'lib/encrypt_attr/encryptor.rb', line 61

def encode(value)
  Base64.encode64(value).chomp
end

#encrypt(value) ⇒ Object 



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# File 'lib/encrypt_attr/encryptor.rb', line 30

def encrypt(value)
  cipher = OpenSSL::Cipher.new(CIPHER).encrypt
  key = Digest::SHA256.digest(secret_token)
  iv = SecureRandom.random_bytes(cipher.iv_len).unpack("H*").first[0...cipher.iv_len]

  cipher.key = key
  cipher.iv = iv

  iv + ";" + encode(cipher.update(value) + cipher.final)
end