Support Ruby 3.4 (#26)

* Add base64 to Gemspec as it's no longer a default gem as of Ruby 3.4

The warning that appears without this change is:

  warning: base64 was loaded from the standard library, but is not part of the default gems starting from Ruby 3.4.0.
  You can add base64 to your Gemfile or gemspec to silence this warning.

* Freeze JWE::Alg::AesKw strings to prevent warnings when using Ruby 3.4

Co-authored-by: Étienne Barrié <[email protected]>

---------

Co-authored-by: Étienne Barrié <[email protected]>

Author: larouxn

jwe.gemspec

@@ -17,4 +17,6 @@ Gem::Specification.new do |s|
 
   s.required_ruby_version = '>= 2.5.0'
   s.metadata['rubygems_mfa_required'] = 'true'
+
+  s.add_dependency 'base64'
 end

lib/jwe/alg/aes_kw.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'jwe/enc/cipher'
 
 module JWE
@@ -8,13 +10,13 @@ module AesKw
       attr_accessor :iv
 
       def initialize(key = nil, iv = "\xA6\xA6\xA6\xA6\xA6\xA6\xA6\xA6")
-        self.iv = iv.force_encoding('ASCII-8BIT')
-        self.key = key.force_encoding('ASCII-8BIT')
+        self.iv = iv.b
+        self.key = key.b
       end
 
       def encrypt(cek)
         a = iv
-        r = cek.force_encoding('ASCII-8BIT').scan(/.{8}/m)
+        r = cek.b.scan(/.{8}/m)
 
         6.times do |j|
           a, r = kw_encrypt_round(j, a, r)
@@ -36,7 +38,7 @@ def kw_encrypt_round(j, a, r)
       end
 
       def decrypt(encrypted_cek)
-        c = encrypted_cek.force_encoding('ASCII-8BIT').scan(/.{8}/m)
+        c = encrypted_cek.b.scan(/.{8}/m)
         a, *r = c
 
         5.downto(0) do |j|