diff --git a/lib/net/smtp/auth_cram_md5.rb b/lib/net/smtp/auth_cram_md5.rb
deleted file mode 100644
index 50994ee..0000000
--- a/lib/net/smtp/auth_cram_md5.rb
+++ /dev/null
@@ -1,53 +0,0 @@
-unless defined? OpenSSL
-  begin
-    require 'digest/md5'
-  rescue LoadError
-  end
-end
-
-class Net::SMTP
-  class AuthCramMD5 < Net::SMTP::Authenticator
-    auth_type :cram_md5
-
-    def auth(user_arg = nil, secret_arg = nil,
-             authcid: nil, username: nil, user: nil,
-             secret: nil, password: nil,
-             **)
-      user   = req_param authcid, username, user, user_arg, "username (authcid)"
-      secret = req_param password, secret, secret_arg,      "secret (password)"
-      challenge = continue('AUTH CRAM-MD5')
-      crammed = cram_md5_response(secret, challenge.unpack1('m'))
-      finish(base64_encode("#{user} #{crammed}"))
-    end
-
-    IMASK = 0x36
-    OMASK = 0x5c
-
-    # CRAM-MD5: [RFC2195]
-    def cram_md5_response(secret, challenge)
-      tmp = digest_class::MD5.digest(cram_secret(secret, IMASK) + challenge)
-      digest_class::MD5.hexdigest(cram_secret(secret, OMASK) + tmp)
-    end
-
-    CRAM_BUFSIZE = 64
-
-    def cram_secret(secret, mask)
-      secret = digest_class::MD5.digest(secret) if secret.size > CRAM_BUFSIZE
-      buf = secret.ljust(CRAM_BUFSIZE, "\0")
-      0.upto(buf.size - 1) do |i|
-        buf[i] = (buf[i].ord ^ mask).chr
-      end
-      buf
-    end
-
-    def digest_class
-      @digest_class ||= if defined?(OpenSSL::Digest)
-                          OpenSSL::Digest
-                        elsif defined?(::Digest)
-                          ::Digest
-                        else
-                          raise '"openssl" or "digest" library is required'
-                        end
-    end
-  end
-end
diff --git a/lib/net/smtp/auth_login.rb b/lib/net/smtp/auth_login.rb
deleted file mode 100644
index 174ab09..0000000
--- a/lib/net/smtp/auth_login.rb
+++ /dev/null
@@ -1,16 +0,0 @@
-class Net::SMTP
-  class AuthLogin < Net::SMTP::Authenticator
-    auth_type :login
-
-    def auth(user_arg = nil, secret_arg = nil,
-             authcid: nil, username: nil, user: nil,
-             secret: nil, password: nil,
-             **)
-      user   = req_param authcid, username, user, user_arg, "username (authcid)"
-      secret = req_param password, secret, secret_arg,      "secret (password)"
-      continue('AUTH LOGIN')
-      continue(base64_encode(user))
-      finish(base64_encode(secret))
-    end
-  end
-end
diff --git a/lib/net/smtp/auth_plain.rb b/lib/net/smtp/auth_plain.rb
deleted file mode 100644
index e778bad..0000000
--- a/lib/net/smtp/auth_plain.rb
+++ /dev/null
@@ -1,14 +0,0 @@
-class Net::SMTP
-  class AuthPlain < Net::SMTP::Authenticator
-    auth_type :plain
-
-    def auth(user_arg = nil, secret_arg = nil,
-             authcid: nil, username: nil, user: nil,
-             secret: nil, password: nil,
-             **)
-      user   = req_param authcid, username, user, user_arg, "username (authcid)"
-      secret = req_param password, secret, secret_arg,      "secret (password)"
-      finish('AUTH PLAIN ' + base64_encode("\0#{user}\0#{secret}"))
-    end
-  end
-end
diff --git a/test/net/smtp/test_smtp.rb b/test/net/smtp/test_smtp.rb
index d2fd19a..de181ff 100644
--- a/test/net/smtp/test_smtp.rb
+++ b/test/net/smtp/test_smtp.rb
@@ -138,23 +138,28 @@ def test_unsucessful_auth_plain
     def test_auth_cram_md5
       server = FakeServer.start(auth: 'CRAM-MD5')
       smtp = Net::SMTP.start 'localhost', server.port
-      assert smtp.auth(:cram_md5, "account", password: "password").success?
+      assert smtp.auth(:cram_md5, "account", password: "password",
+                       warn_deprecation: false).success?
     end
 
     def test_auth_login
       server = FakeServer.start(auth: 'login')
       smtp = Net::SMTP.start 'localhost', server.port
-      assert smtp.authenticate("account", "password", :login).success?
+      assert smtp.auth(:login, "account", "password",
+                       warn_deprecation: false).success?
 
       server = FakeServer.start(auth: 'login')
       smtp = Net::SMTP.start 'localhost', server.port
-      assert smtp.auth("LOGIN", username: "account", secret: "password").success?
+      assert smtp.auth(username: "account", secret: "password",
+                       type: :login, warn_deprecation: false).success?
     end
 
     def test_unsucessful_auth_login
       server = FakeServer.start(auth: 'login')
       smtp = Net::SMTP.start 'localhost', server.port
-      err = assert_raise(Net::SMTPAuthenticationError) { smtp.authenticate("foo", "bar", :login) }
+      err = assert_raise(Net::SMTPAuthenticationError) {
+        smtp.auth(:login, "foo", "bar", warn_deprecation: false)
+      }
       assert_equal "535 5.7.8 Error: authentication failed: authentication failure\n", err.message
       assert_equal "535", err.response.status
     end
@@ -167,7 +172,9 @@ def server.auth(*)
         @sock.puts "235 2.7.0 Authentication successful\r\n"
       end
       smtp = Net::SMTP.start 'localhost', server.port
-      err = assert_raise(Net::SMTPUnknownError) { smtp.authenticate("account", "password", :login) }
+      err = assert_raise(Net::SMTPUnknownError) {
+        smtp.auth(:login, "account", "password", warn_deprecation: false)
+      }
       assert_equal "235 2.7.0 Authentication successful\n", err.message
       assert_equal "235", err.response.status
     end
@@ -502,16 +509,19 @@ def test_start_auth_plain
 
     def test_start_auth_login
       port = fake_server_start(auth: 'LOGIN')
-      Net::SMTP.start('localhost', port, user: 'account', password: 'password', authtype: :login){}
+      Net::SMTP.start('localhost', port, user: 'account', password: 'password',
+                      authtype: :login, auth: {warn_deprecation: false}){}
 
       port = fake_server_start(auth: 'LOGIN')
       assert_raise Net::SMTPAuthenticationError do
-        Net::SMTP.start('localhost', port, user: 'account', password: 'invalid', authtype: :login){}
+        Net::SMTP.start('localhost', port, user: 'account', password: 'invalid',
+                        authtype: :login, auth: {warn_deprecation: false}){}
       end
 
       port = fake_server_start(auth: 'PLAIN')
       assert_raise Net::SMTPAuthenticationError do
-        Net::SMTP.start('localhost', port, user: 'account', password: 'password', authtype: :login){}
+        Net::SMTP.start('localhost', port, user: 'account', password: 'password',
+                        authtype: :login, auth: {warn_deprecation: false}){}
       end
     end
 
@@ -519,16 +529,19 @@ def test_start_auth_cram_md5
       omit "openssl or digest library not loaded" unless defined? OpenSSL or defined? Digest
 
       port = fake_server_start(auth: 'CRAM-MD5')
-      Net::SMTP.start('localhost', port, user: 'account', password: 'password', authtype: "CRAM-MD5"){}
+      Net::SMTP.start('localhost', port, user: 'account', password: 'password',
+                      authtype: "CRAM-MD5", auth: {warn_deprecation: false}){}
 
       port = fake_server_start(auth: 'CRAM-MD5')
       assert_raise Net::SMTPAuthenticationError do
-        Net::SMTP.start('localhost', port, user: 'account', password: 'invalid', authtype: :cram_md5){}
+        Net::SMTP.start('localhost', port, user: 'account', password: 'invalid',
+                        authtype: :cram_md5, auth: {warn_deprecation: false}){}
       end
 
       port = fake_server_start(auth: 'PLAIN')
       assert_raise Net::SMTPAuthenticationError do
-        Net::SMTP.start('localhost', port, user: 'account', password: 'password', authtype: :cram_md5){}
+        Net::SMTP.start('localhost', port, user: 'account', password: 'password',
+                        authtype: :cram_md5, auth: {warn_deprecation: false}){}
       end
     end