Class: Pubnub::Crypto::LegacyCryptor

Inherits:
Cryptor show all
Defined in:
lib/pubnub/modules/crypto/cryptors/legacy_cryptor.rb

Overview

Legacy cryptor.

The cryptor provides encryption and decryption using `AES-256 in CBC mode with a cipher key and configurable initialization vector randomness. When it is registered as a secondary with other cryptors, it will provide backward compatibility with previously encrypted data.

Important: It has been reported that the digest from cipherKey has low entropy, and it is suggested to use AesCbcCryptor instead.

Constant Summary collapse

BLOCK_SIZE =

AES-128 CBC block size.

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Instance Method Summary collapse

Constructor Details

#initialize(cipher_key, use_random_iv = true) ⇒ LegacyCryptor

Create legacy cryptor instance.



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# File 'lib/pubnub/modules/crypto/cryptors/legacy_cryptor.rb', line 22

def initialize(cipher_key, use_random_iv = true)
  @alg = 'AES-256-CBC'
  @original_cipher_key = cipher_key
  @cipher_key = Digest::SHA256.hexdigest(cipher_key.to_s).slice(0, 32)
  @iv = use_random_iv ? nil : '0123456789012345'
  super()
end

Instance Method Details

#decrypt(data) ⇒ Object 



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# File 'lib/pubnub/modules/crypto/cryptors/legacy_cryptor.rb', line 55

def decrypt(data)
  encrypted_data = data.data
  iv = if @iv.nil? && encrypted_data.length >= BLOCK_SIZE
         encrypted_data.slice!(0..(BLOCK_SIZE - 1)) if encrypted_data.length >= BLOCK_SIZE
       else
         @iv
       end
  if iv.length != BLOCK_SIZE
    puts "Pubnub :: DECRYPTION ERROR: Unexpected initialization vector length: #{data.metadata.length} bytes (#{BLOCK_SIZE} bytes is expected)"
    return nil
  end

  unless encrypted_data.length.positive?
    puts 'Pubnub :: DECRYPTION ERROR: Empty data for decryption'
    return nil
  end

  cipher = OpenSSL::Cipher.new(@alg).decrypt
  cipher.key = @cipher_key
  cipher.iv = iv

  decrypted = cipher.update encrypted_data
  decrypted << cipher.final
rescue StandardError => e
  puts "Pubnub :: DECRYPTION ERROR: #{e}"
  nil
end

#encrypt(data) ⇒ Object 



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# File 'lib/pubnub/modules/crypto/cryptors/legacy_cryptor.rb', line 34

def encrypt(data)
  if data.nil? || data.empty?
    puts 'Pubnub :: ENCRYPTION ERROR: Empty data for encryption'
    return nil
  end

  iv = @iv || OpenSSL::Random.random_bytes(BLOCK_SIZE)
  cipher = OpenSSL::Cipher.new(@alg).encrypt
  cipher.key = @cipher_key
  cipher.iv = iv

  encoded_message = ''
  encoded_message << iv if @iv.nil? && iv
  encoded_message << cipher.update(data)
  encoded_message << cipher.final
  Crypto::EncryptedData.new(encoded_message)
rescue StandardError => e
  puts "Pubnub :: ENCRYPTION ERROR: #{e}"
  nil
end

#identifier ⇒ Object 



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# File 'lib/pubnub/modules/crypto/cryptors/legacy_cryptor.rb', line 30

def identifier
  '\x00\x00\x00\x00'
end