Fix nil iv error

lib/cryptology.rb

@@ -20,15 +20,15 @@ def self.encrypt_data(data, key, algorithm, iv)
       cipher = ::OpenSSL::Cipher::Cipher.new(algorithm)
       cipher.encrypt
       cipher.key = key
-      cipher.iv = iv
+      cipher.iv = iv unless iv.nil?
       cipher.update(data) + cipher.final
     end
 
     def self.decrypt_data(encrypted_data, key, algorithm, iv)
       decipher = ::OpenSSL::Cipher::Cipher.new(algorithm)
       decipher.decrypt
       decipher.key = key
-      decipher.iv = iv
+      decipher.iv = iv unless iv.nil?
       decipher.update(encrypted_data) + decipher.final
     end
 

spec/cryptology_spec.rb

@@ -37,6 +37,13 @@
                 SEED-CBC)
 
 describe Cryptology do
+  it 'encrypts and decrypts with default arguments' do
+    data      = 'Very confidential data with UTF-8 symbols: ♠ я ü æ'
+    key       = 'veryLongAndSecurePassword_6154309'
+    encrypted = Cryptology.encrypt(data, key)
+    expect(Cryptology.decrypt(encrypted, key)).to eq data
+  end
+
   context 'encryption' do
     ALGORITHMS.each do |alg|
       it "encrypts #{alg}" do