Fix accessor lint issues

Author: anakinj

.rubocop_todo.yml

@@ -6,12 +6,6 @@
 # Note that changes in the inspected code, or installation of new
 # versions of RuboCop, may require this file to be generated again.
 
-# Offense count: 6
-Lint/DuplicateMethods:
-  Exclude:
-    - 'lib/jwe/enc/aes_cbc_hs.rb'
-    - 'lib/jwe/enc/aes_gcm.rb'
-
 # Offense count: 15
 # Configuration parameters: MinNameLength, AllowNamesEndingInNumbers, AllowedNames, ForbiddenNames.
 # AllowedNames: as, at, by, cc, db, id, if, in, io, ip, of, on, os, pp, to

lib/jwe/enc/aes_cbc_hs.rb

@@ -6,7 +6,7 @@ module JWE
   module Enc
     # Abstract AES in Block cipher mode, with message signature for different key sizes.
     module AesCbcHs
-      attr_accessor :cek, :iv, :tag
+      attr_writer :cek, :iv, :tag
 
       def initialize(cek = nil, iv = nil)
         self.iv = iv

lib/jwe/enc/aes_gcm.rb

@@ -6,7 +6,7 @@ module JWE
   module Enc
     # Abstract AES in Galois Counter mode for different key sizes.
     module AesGcm
-      attr_accessor :cek, :iv, :tag
+      attr_writer :iv, :cek, :tag
 
       def initialize(cek = nil, iv = nil)
         self.iv = iv