diff --git a/README.md b/README.md
index 36ad1eeb..0b2e0c16 100644
--- a/README.md
+++ b/README.md
@@ -715,6 +715,7 @@ Profile on LeetCode: [fartem](https://leetcode.com/fartem/).
 | 1706. Where Will the Ball Fall                                                      | [Link](https://leetcode.com/problems/where-will-the-ball-fall/)                                                      | [Link](./lib/medium/1706_where_will_the_ball_fall.rb)                                                      | [Link](./test/medium/test_1706_where_will_the_ball_fall.rb)                                                      |
 | 1721. Swapping Nodes in a Linked List                                               | [Link](https://leetcode.com/problems/swapping-nodes-in-a-linked-list/)                                               | [Link](./lib/medium/1721_swapping_nodes_in_a_linked_list.rb)                                               | [Link](./test/medium/test_1721_swapping_nodes_in_a_linked_list.rb)                                               |
 | 1780. Check if Number is a Sum of Powers of Three                                   | [Link](https://leetcode.com/problems/check-if-number-is-a-sum-of-powers-of-three/)                                   | [Link](./lib/medium/1780_check_if_number_is_a_sum_of_powers_of_three.rb)                                   | [Link](./test/medium/test_1780_check_if_number_is_a_sum_of_powers_of_three.rb)                                   |
+| 1797. Design Authentication Manager                                                 | [Link](https://leetcode.com/problems/design-authentication-manager/)                                                 | [Link](./lib/medium/1797_design_authentication_manager.rb)                                                 | [Link](./test/medium/test_1797_design_authentication_manager.rb)                                                 |
 | 2116. Check if a Parentheses String Can Be Valid                                    | [Link](https://leetcode.com/problems/check-if-a-parentheses-string-can-be-valid/)                                    | [Link](./lib/medium/2116_check_if_a_parentheses_string_can_be_valid.rb)                                    | [Link](./test/medium/test_2116_check_if_a_parentheses_string_can_be_valid.rb)                                    |
 | 2425. Bitwise XOR of All Pairings                                                   | [Link](https://leetcode.com/problems/bitwise-xor-of-all-pairings/)                                                   | [Link](./lib/medium/2425_bitwise_xor_of_all_pairings.rb)                                                   | [Link](./test/medium/test_2425_bitwise_xor_of_all_pairings.rb)                                                   |
 | 2429. Minimize XOR                                                                  | [Link](https://leetcode.com/problems/minimize-xor/)                                                                  | [Link](./lib/medium/2429_minimize_xor.rb)                                                                  | [Link](./test/medium/test_2429_minimize_xor.rb)                                                                  |
diff --git a/leetcode-ruby.gemspec b/leetcode-ruby.gemspec
index c7114933..4938bbe5 100644
--- a/leetcode-ruby.gemspec
+++ b/leetcode-ruby.gemspec
@@ -5,7 +5,7 @@ require 'English'
 ::Gem::Specification.new do |s|
   s.required_ruby_version = '>= 3.0'
   s.name = 'leetcode-ruby'
-  s.version = '8.8.1'
+  s.version = '8.8.2'
   s.license = 'MIT'
   s.files = ::Dir['lib/**/*.rb'] + %w[README.md]
   s.executable = 'leetcode-ruby'
diff --git a/lib/medium/1797_design_authentication_manager.rb b/lib/medium/1797_design_authentication_manager.rb
new file mode 100644
index 00000000..5d4afb2d
--- /dev/null
+++ b/lib/medium/1797_design_authentication_manager.rb
@@ -0,0 +1,38 @@
+# frozen_string_literal: true
+
+# https://leetcode.com/problems/design-authentication-manager/
+class AuthenticationManager
+  # @param {Integer} time_to_live
+  def initialize(time_to_live)
+    @time_to_live = time_to_live
+    @auth = {}
+    @tokens = ::Set.new
+  end
+
+  # @param {String} token_id
+  # @param {Integer} current_time
+  # @return {Void}
+  def generate(token_id, current_time)
+    @auth[token_id] = current_time + @time_to_live
+    @tokens << token_id
+  end
+
+  # @param {String} token_id
+  # @param {Integer} current_time
+  # @return {Void}
+  def renew(token_id, current_time)
+    time = @auth.fetch(token_id, 0)
+
+    return unless time > current_time
+
+    generate(token_id, current_time)
+
+    @tokens << token_id
+  end
+
+  # @param {Integer} current_time
+  # @return {Integer}
+  def count_unexpired_tokens(current_time)
+    @tokens.count { |token| @auth[token] > current_time }
+  end
+end
diff --git a/test/medium/test_1797_design_authentication_manager.rb b/test/medium/test_1797_design_authentication_manager.rb
new file mode 100644
index 00000000..49ed231b
--- /dev/null
+++ b/test/medium/test_1797_design_authentication_manager.rb
@@ -0,0 +1,27 @@
+# frozen_string_literal: true
+
+require_relative '../test_helper'
+require_relative '../../lib/medium/1797_design_authentication_manager'
+require 'minitest/autorun'
+
+class DesignAuthenticationManagerTest < ::Minitest::Test
+  def test_default_one
+    authentication_manager = ::AuthenticationManager.new(5)
+    authentication_manager.renew('aaa', 1)
+    authentication_manager.generate('aaa', 2)
+
+    assert_equal(
+      1,
+      authentication_manager.count_unexpired_tokens(6)
+    )
+
+    authentication_manager.generate('bbb', 7)
+    authentication_manager.renew('aaa', 8)
+    authentication_manager.renew('bbb', 10)
+
+    assert_equal(
+      0,
+      authentication_manager.count_unexpired_tokens(15)
+    )
+  end
+end