Add sha2-{256,512}-etm@openssh.com MAC algorithms

Implement the Encrypt-Then-Mac versions of the SHA2-256 and SHA2-512
MACs. These MACs are implemented by openssh and may be the only MACs
available on a hardened installation of openssh.

With EtM the MAC is calculated over the unencrypted packet length and
the encrypted payload (which includes padding length and padding).

The main benefit of EtM schemes is that it allows the encrypted
payload to be authenticated before it gets passed to the encryption
engine. This patch does not implement that mechanism, but this can be
added later to the poll_next_packet method. Note that all current MACs
already pass unauthenticated data to the encryption engine.

14 files changed, 332 insertions, 31 deletions

diff --git a/.rubocop_todo.yml b/.rubocop_todo.yml
index 8ca8930..bc4efd8 100644
--- a/.rubocop_todo.yml
+++ b/.rubocop_todo.yml
@@ -253,7 +253,7 @@ Lint/UselessAssignment:
 
 # Offense count: 229
 Metrics/AbcSize:
-  Max: 69
+  Max: 89
 
 # Offense count: 15
 # Configuration parameters: CountComments, ExcludedMethods.
@@ -283,7 +283,7 @@ Metrics/MethodLength:
 # Offense count: 2
 # Configuration parameters: CountComments.
 Metrics/ModuleLength:
-  Max: 138
+  Max: 160
 
 # Offense count: 1
 # Configuration parameters: CountKeywordArgs.
@@ -317,14 +317,18 @@ Naming/ClassAndModuleCamelCase:
     - 'lib/net/ssh/transport/hmac/sha1_96.rb'
     - 'lib/net/ssh/transport/hmac/sha2_256.rb'
     - 'lib/net/ssh/transport/hmac/sha2_256_96.rb'
+    - 'lib/net/ssh/transport/hmac/sha2_256_etm.rb'
     - 'lib/net/ssh/transport/hmac/sha2_512.rb'
     - 'lib/net/ssh/transport/hmac/sha2_512_96.rb'
+    - 'lib/net/ssh/transport/hmac/sha2_512_etm.rb'
     - 'test/transport/hmac/test_md5_96.rb'
     - 'test/transport/hmac/test_sha1_96.rb'
     - 'test/transport/hmac/test_sha2_256.rb'
     - 'test/transport/hmac/test_sha2_256_96.rb'
+    - 'test/transport/hmac/test_sha2_256_etm.rb'
     - 'test/transport/hmac/test_sha2_512.rb'
     - 'test/transport/hmac/test_sha2_512_96.rb'
+    - 'test/transport/hmac/test_sha2_512_etm.rb'
 
 # Offense count: 4
 Naming/ConstantName:
@@ -496,8 +500,10 @@ Style/ClassAndModuleChildren:
     - 'lib/net/ssh/transport/hmac/sha1_96.rb'
     - 'lib/net/ssh/transport/hmac/sha2_256.rb'
     - 'lib/net/ssh/transport/hmac/sha2_256_96.rb'
+    - 'lib/net/ssh/transport/hmac/sha2_256_etm.rb'
     - 'lib/net/ssh/transport/hmac/sha2_512.rb'
     - 'lib/net/ssh/transport/hmac/sha2_512_96.rb'
+    - 'lib/net/ssh/transport/hmac/sha2_512_etm.rb'
     - 'lib/net/ssh/transport/kex.rb'
     - 'lib/net/ssh/transport/kex/diffie_hellman_group_exchange_sha1.rb'
     - 'lib/net/ssh/transport/kex/diffie_hellman_group_exchange_sha256.rb'
diff --git a/README.md b/README.md
index e00321c..4fc8ec8 100644
--- a/README.md
+++ b/README.md
@@ -76,6 +76,8 @@ Unsecure algoritms will be definively remove in Net::SSH 7.*.
 
 | Name                 | Support               | Details  |
 |----------------------|-----------------------|----------|
+| hmac-sha2-512-etm    | OK                    |          |
+| hmac-sha2-256-etm    | OK                    |          |
 | hmac-sha2-512        | OK                    |          |
 | hmac-sha2-256        | OK                    |          |
 | hmac-sha2-512-96     | Deprecated in 5.3     | removed from the specification, will be removed in 6.0 |
diff --git a/lib/net/ssh/transport/algorithms.rb b/lib/net/ssh/transport/algorithms.rb
index 830fa71..86059dd 100644
--- a/lib/net/ssh/transport/algorithms.rb
+++ b/lib/net/ssh/transport/algorithms.rb
@@ -43,7 +43,8 @@ module Net
 
           encryption: %w[aes256-ctr aes192-ctr aes128-ctr],
 
-          hmac: %w[hmac-sha2-512 hmac-sha2-256
+          hmac: %w[hmac-sha2-512-etm@openssh.com hmac-sha2-256-etm@openssh.com
+                   hmac-sha2-512 hmac-sha2-256
                    hmac-sha1]
         }.freeze
 
diff --git a/lib/net/ssh/transport/hmac.rb b/lib/net/ssh/transport/hmac.rb
index d8560eb..0905050 100644
--- a/lib/net/ssh/transport/hmac.rb
+++ b/lib/net/ssh/transport/hmac.rb
@@ -7,6 +7,8 @@ require 'net/ssh/transport/hmac/sha2_256'
 require 'net/ssh/transport/hmac/sha2_256_96'
 require 'net/ssh/transport/hmac/sha2_512'
 require 'net/ssh/transport/hmac/sha2_512_96'
+require 'net/ssh/transport/hmac/sha2_256_etm'
+require 'net/ssh/transport/hmac/sha2_512_etm'
 require 'net/ssh/transport/hmac/ripemd160'
 require 'net/ssh/transport/hmac/none'
 
@@ -15,17 +17,19 @@ require 'net/ssh/transport/hmac/none'
 module Net::SSH::Transport::HMAC
   # The mapping of SSH hmac algorithms to their implementations
   MAP = {
-    'hmac-md5'         => MD5,
-    'hmac-md5-96'      => MD5_96,
-    'hmac-sha1'        => SHA1,
-    'hmac-sha1-96'     => SHA1_96,
-    'hmac-sha2-256'    => SHA2_256,
-    'hmac-sha2-256-96' => SHA2_256_96,
-    'hmac-sha2-512'    => SHA2_512,
-    'hmac-sha2-512-96' => SHA2_512_96,
-    'hmac-ripemd160'   => RIPEMD160,
-    'hmac-ripemd160@openssh.com' => RIPEMD160,
-    'none' => None
+    'hmac-md5'                      => MD5,
+    'hmac-md5-96'                   => MD5_96,
+    'hmac-sha1'                     => SHA1,
+    'hmac-sha1-96'                  => SHA1_96,
+    'hmac-sha2-256'                 => SHA2_256,
+    'hmac-sha2-256-96'              => SHA2_256_96,
+    'hmac-sha2-512'                 => SHA2_512,
+    'hmac-sha2-512-96'              => SHA2_512_96,
+    'hmac-sha2-256-etm@openssh.com' => SHA2_256_Etm,
+    'hmac-sha2-512-etm@openssh.com' => SHA2_512_Etm,
+    'hmac-ripemd160'                => RIPEMD160,
+    'hmac-ripemd160@openssh.com'    => RIPEMD160,
+    'none'                          => None
   }
 
   # Retrieves a new hmac instance of the given SSH type (+name+). If +key+ is
diff --git a/lib/net/ssh/transport/hmac/abstract.rb b/lib/net/ssh/transport/hmac/abstract.rb
index 22ad9a6..f8efa3e 100644
--- a/lib/net/ssh/transport/hmac/abstract.rb
+++ b/lib/net/ssh/transport/hmac/abstract.rb
@@ -9,6 +9,18 @@ module Net
         # The base class of all OpenSSL-based HMAC algorithm wrappers.
         class Abstract
           class <<self
+            def etm(*v)
+              @etm = false if !defined?(@etm)
+              if v.empty?
+                @etm = superclass.etm if @etm.nil? && superclass.respond_to?(:etm)
+                return @etm
+              elsif v.length == 1
+                @etm = v.first
+              else
+                raise ArgumentError, "wrong number of arguments (#{v.length} for 1)"
+              end
+            end
+
             def key_length(*v)
               @key_length = nil if !defined?(@key_length)
               if v.empty?
@@ -46,6 +58,10 @@ module Net
             end
           end
 
+          def etm
+            self.class.etm
+          end
+
           def key_length
             self.class.key_length
           end
diff --git a/lib/net/ssh/transport/hmac/sha2_256_etm.rb b/lib/net/ssh/transport/hmac/sha2_256_etm.rb
new file mode 100644
index 0000000..d7ac12b
--- /dev/null
+++ b/lib/net/ssh/transport/hmac/sha2_256_etm.rb
@@ -0,0 +1,12 @@
+require 'net/ssh/transport/hmac/abstract'
+
+module Net::SSH::Transport::HMAC
+  # The SHA-256 Encrypt-Then-Mac HMAC algorithm. This has a mac and
+  # key length of 32, and uses the SHA-256 digest algorithm.
+  class SHA2_256_Etm < Abstract
+    etm          true
+    mac_length   32
+    key_length   32
+    digest_class OpenSSL::Digest::SHA256
+  end
+end
diff --git a/lib/net/ssh/transport/hmac/sha2_512_etm.rb b/lib/net/ssh/transport/hmac/sha2_512_etm.rb
new file mode 100644
index 0000000..8b7af6d
--- /dev/null
+++ b/lib/net/ssh/transport/hmac/sha2_512_etm.rb
@@ -0,0 +1,12 @@
+require 'net/ssh/transport/hmac/abstract'
+
+module Net::SSH::Transport::HMAC
+  # The SHA-512 Encrypt-Then-Mac HMAC algorithm. This has a mac and
+  # key length of 64, and uses the SHA-512 digest algorithm.
+  class SHA2_512_Etm < Abstract
+    etm          true
+    mac_length   64
+    key_length   64
+    digest_class OpenSSL::Digest::SHA512
+  end
+end
diff --git a/lib/net/ssh/transport/packet_stream.rb b/lib/net/ssh/transport/packet_stream.rb
index a290316..65b55f2 100644
--- a/lib/net/ssh/transport/packet_stream.rb
+++ b/lib/net/ssh/transport/packet_stream.rb
@@ -130,7 +130,7 @@ module Net
           payload = client.compress(payload)
 
           # the length of the packet, minus the padding
-          actual_length = 4 + payload.bytesize + 1
+          actual_length = (client.hmac.etm ? 0 : 4) + payload.bytesize + 1
 
           # compute the padding length
           padding_length = client.block_size - (actual_length % client.block_size)
@@ -146,11 +146,32 @@ module Net
 
           padding = Array.new(padding_length) { rand(256) }.pack("C*")
 
-          unencrypted_data = [packet_length, padding_length, payload, padding].pack("NCA*A*")
-          mac = client.hmac.digest([client.sequence_number, unencrypted_data].pack("NA*"))
+          if client.hmac.etm
+            debug { "using encrypt-then-mac" }
 
-          encrypted_data = client.update_cipher(unencrypted_data) << client.final_cipher
-          message = encrypted_data + mac
+            # Encrypt padding_length, payload, and padding. Take MAC
+            # from the unencrypted packet_lenght and the encrypted
+            # data.
+            length_data = [packet_length].pack("N")
+
+            unencrypted_data = [padding_length, payload, padding].pack("CA*A*")
+
+            encrypted_data = client.update_cipher(unencrypted_data) << client.final_cipher
+
+            mac_data = length_data + encrypted_data
+
+            mac = client.hmac.digest([client.sequence_number, mac_data].pack("NA*"))
+
+            message = mac_data + mac
+          else
+            unencrypted_data = [packet_length, padding_length, payload, padding].pack("NCA*A*")
+
+            mac = client.hmac.digest([client.sequence_number, unencrypted_data].pack("NA*"))
+
+            encrypted_data = client.update_cipher(unencrypted_data) << client.final_cipher
+
+            message = encrypted_data + mac
+          end
 
           debug { "queueing packet nr #{client.sequence_number} type #{payload.getbyte(0)} len #{packet_length}" }
           enqueue(message)
@@ -196,17 +217,25 @@ module Net
         # algorithms specified in the server state object, and returned as a
         # new Packet object.
         def poll_next_packet
+          aad_length = server.hmac.etm ? 4 : 0
+
           if @packet.nil?
             minimum = server.block_size < 4 ? 4 : server.block_size
             return nil if available < minimum
-            data = read_available(minimum)
+            data = read_available(minimum + aad_length)
 
             # decipher it
-            @packet = Net::SSH::Buffer.new(server.update_cipher(data))
-            @packet_length = @packet.read_long
+            if server.hmac.etm
+              @packet_length = data.unpack("N").first
+              @mac_data = data
+              @packet = Net::SSH::Buffer.new(server.update_cipher(data[aad_length..-1]))
+            else
+              @packet = Net::SSH::Buffer.new(server.update_cipher(data))
+              @packet_length = @packet.read_long
+            end
           end
 
-          need = @packet_length + 4 - server.block_size
+          need = @packet_length + 4 - aad_length - server.block_size
           raise Net::SSH::Exception, "padding error, need #{need} block #{server.block_size}" if need % server.block_size != 0
 
           return nil if available < need + server.hmac.mac_length
@@ -214,6 +243,7 @@ module Net
           if need > 0
             # read the remainder of the packet and decrypt it.
             data = read_available(need)
+            @mac_data += data if server.hmac.etm
             @packet.append(server.update_cipher(data))
           end
 
@@ -226,7 +256,11 @@ module Net
 
           payload = @packet.read(@packet_length - padding_length - 1)
 
-          my_computed_hmac = server.hmac.digest([server.sequence_number, @packet.content].pack("NA*"))
+          my_computed_hmac = if server.hmac.etm
+                               server.hmac.digest([server.sequence_number, @mac_data].pack("NA*"))
+                             else
+                               server.hmac.digest([server.sequence_number, @packet.content].pack("NA*"))
+                             end
           raise Net::SSH::Exception, "corrupted hmac detected" if real_hmac != my_computed_hmac
 
           # try to decompress the payload, in case compression is active
diff --git a/test/transport/hmac/test_sha2_256.rb b/test/transport/hmac/test_sha2_256.rb
index dbf0ffc..8a2e07d 100644
--- a/test/transport/hmac/test_sha2_256.rb
+++ b/test/transport/hmac/test_sha2_256.rb
@@ -22,6 +22,11 @@ module Transport
         assert_equal 32, subject.new.mac_length
       end
 
+      def test_expected_etm
+        assert_equal false, subject.etm
+        assert_equal false, subject.new.etm
+      end
+
       def test_expected_digest
         hmac = subject.new("1234567890123456")
         assert_equal "\x16^>\x9FhO}\xB1>(\xBAF\xFBW\xB8\xF2\xFA\x824+\xC0\x94\x95\xC2\r\xE6\x88/\xEF\t\xF5%", hmac.digest("hello world")
diff --git a/test/transport/hmac/test_sha2_256_etm.rb b/test/transport/hmac/test_sha2_256_etm.rb
new file mode 100644
index 0000000..f66afda
--- /dev/null
+++ b/test/transport/hmac/test_sha2_256_etm.rb
@@ -0,0 +1,42 @@
+# encoding: ASCII-8BIT
+
+require 'common'
+require 'net/ssh/transport/hmac/sha2_256_etm'
+
+module Transport
+  module HMAC
+
+    class TestSHA2_256_Etm < NetSSHTest
+      def test_expected_digest_class
+        assert_equal OpenSSL::Digest::SHA256, subject.digest_class
+        assert_equal OpenSSL::Digest::SHA256, subject.new.digest_class
+      end
+
+      def test_expected_key_length
+        assert_equal 32, subject.key_length
+        assert_equal 32, subject.new.key_length
+      end
+
+      def test_expected_mac_length
+        assert_equal 32, subject.mac_length
+        assert_equal 32, subject.new.mac_length
+      end
+
+      def test_expected_etm
+        assert_equal true, subject.etm
+        assert_equal true, subject.new.etm
+      end
+
+      def test_expected_digest
+        hmac = subject.new("1234567890123456")
+        assert_equal "\x16^>\x9FhO}\xB1>(\xBAF\xFBW\xB8\xF2\xFA\x824+\xC0\x94\x95\xC2\r\xE6\x88/\xEF\t\xF5%", hmac.digest("hello world")
+      end
+
+      private
+
+      def subject
+        Net::SSH::Transport::HMAC::SHA2_256_Etm
+      end
+    end
+  end
+end
diff --git a/test/transport/hmac/test_sha2_512.rb b/test/transport/hmac/test_sha2_512.rb
index dc25fd8..886c683 100644
--- a/test/transport/hmac/test_sha2_512.rb
+++ b/test/transport/hmac/test_sha2_512.rb
@@ -22,6 +22,11 @@ module Transport
         assert_equal 64, subject.new.mac_length
       end
 
+      def test_expected_etm
+        assert_equal false, subject.etm
+        assert_equal false, subject.new.etm
+      end
+
       def test_expected_digest
         hmac = subject.new("1234567890123456")
         assert_equal "^\xB6\"\xED\x8B\xC4\xDE\xD4\xCF\xD0\r\x18\xA0<\xF4\xB5\x01Efz\xA80i\xFC\x18\xC1\x9A+\xDD\xFE<\xA2\xFDE1Ac\xF4\xADU\r\xFB^0\x90= \x837z\xCC\xD5p4a4\x83\xC6\x04m\xAA\xC1\xC0m", hmac.digest("hello world")
diff --git a/test/transport/hmac/test_sha2_512_etm.rb b/test/transport/hmac/test_sha2_512_etm.rb
new file mode 100644
index 0000000..364905e
--- /dev/null
+++ b/test/transport/hmac/test_sha2_512_etm.rb
@@ -0,0 +1,42 @@
+# encoding: ASCII-8BIT
+
+require 'common'
+require 'net/ssh/transport/hmac/sha2_512_etm'
+
+module Transport
+  module HMAC
+
+    class TestSHA2_512_Etm < NetSSHTest
+      def test_expected_digest_class
+        assert_equal OpenSSL::Digest::SHA512, subject.digest_class
+        assert_equal OpenSSL::Digest::SHA512, subject.new.digest_class
+      end
+
+      def test_expected_key_length
+        assert_equal 64, subject.key_length
+        assert_equal 64, subject.new.key_length
+      end
+
+      def test_expected_mac_length
+        assert_equal 64, subject.mac_length
+        assert_equal 64, subject.new.mac_length
+      end
+
+      def test_expected_etm
+        assert_equal true, subject.etm
+        assert_equal true, subject.new.etm
+      end
+
+      def test_expected_digest
+        hmac = subject.new("1234567890123456")
+        assert_equal "^\xB6\"\xED\x8B\xC4\xDE\xD4\xCF\xD0\r\x18\xA0<\xF4\xB5\x01Efz\xA80i\xFC\x18\xC1\x9A+\xDD\xFE<\xA2\xFDE1Ac\xF4\xADU\r\xFB^0\x90= \x837z\xCC\xD5p4a4\x83\xC6\x04m\xAA\xC1\xC0m", hmac.digest("hello world")
+      end
+
+      private
+
+      def subject
+        Net::SSH::Transport::HMAC::SHA2_512_Etm
+      end
+    end
+  end
+end
diff --git a/test/transport/test_algorithms.rb b/test/transport/test_algorithms.rb
index eb91887..e2384ff 100644
--- a/test/transport/test_algorithms.rb
+++ b/test/transport/test_algorithms.rb
@@ -21,7 +21,7 @@ module Transport
       assert_equal ed_ec_host_keys + %w[ssh-rsa-cert-v01@openssh.com ssh-rsa-cert-v00@openssh.com ssh-rsa], algorithms[:host_key]
       assert_equal x25519_kex + ec_kex + %w[diffie-hellman-group-exchange-sha256 diffie-hellman-group14-sha1], algorithms[:kex]
       assert_equal %w[aes256-ctr aes192-ctr aes128-ctr], algorithms[:encryption]
-      assert_equal %w[hmac-sha2-512 hmac-sha2-256 hmac-sha1], algorithms[:hmac]
+      assert_equal %w[hmac-sha2-512-etm@openssh.com hmac-sha2-256-etm@openssh.com hmac-sha2-512 hmac-sha2-256 hmac-sha1], algorithms[:hmac]
       assert_equal %w[none zlib@openssh.com zlib], algorithms[:compression]
       assert_equal %w[], algorithms[:language]
     end
@@ -30,7 +30,7 @@ module Transport
       assert_equal ed_ec_host_keys + %w[ssh-rsa-cert-v01@openssh.com ssh-rsa-cert-v00@openssh.com ssh-rsa ssh-dss], algorithms(append_all_supported_algorithms: true)[:host_key]
       assert_equal x25519_kex + ec_kex + %w[diffie-hellman-group-exchange-sha256 diffie-hellman-group14-sha1 diffie-hellman-group-exchange-sha1 diffie-hellman-group1-sha1], algorithms(append_all_supported_algorithms: true)[:kex]
       assert_equal %w[aes256-ctr aes192-ctr aes128-ctr aes256-cbc aes192-cbc aes128-cbc rijndael-cbc@lysator.liu.se blowfish-ctr blowfish-cbc cast128-ctr cast128-cbc 3des-ctr 3des-cbc idea-cbc none], algorithms(append_all_supported_algorithms: true)[:encryption]
-      assert_equal %w[hmac-sha2-512 hmac-sha2-256 hmac-sha1 hmac-sha2-512-96 hmac-sha2-256-96 hmac-sha1-96 hmac-ripemd160 hmac-ripemd160@openssh.com hmac-md5 hmac-md5-96 none], algorithms(append_all_supported_algorithms: true)[:hmac]
+      assert_equal %w[hmac-sha2-512-etm@openssh.com hmac-sha2-256-etm@openssh.com hmac-sha2-512 hmac-sha2-256 hmac-sha1 hmac-sha2-512-96 hmac-sha2-256-96 hmac-sha1-96 hmac-ripemd160 hmac-ripemd160@openssh.com hmac-md5 hmac-md5-96 none], algorithms(append_all_supported_algorithms: true)[:hmac]
       assert_equal %w[none zlib@openssh.com zlib], algorithms(append_all_supported_algorithms: true)[:compression]
       assert_equal %w[], algorithms[:language]
     end
@@ -112,15 +112,15 @@ module Transport
     end
 
     def test_constructor_with_preferred_hmac_should_put_preferred_hmac_first
-      assert_equal %w[hmac-md5-96 hmac-sha2-512 hmac-sha2-256 hmac-sha1 hmac-sha2-512-96 hmac-sha2-256-96 hmac-sha1-96 hmac-ripemd160 hmac-ripemd160@openssh.com hmac-md5 none], algorithms(hmac: "hmac-md5-96", append_all_supported_algorithms: true)[:hmac]
+      assert_equal %w[hmac-md5-96 hmac-sha2-512-etm@openssh.com hmac-sha2-256-etm@openssh.com hmac-sha2-512 hmac-sha2-256 hmac-sha1 hmac-sha2-512-96 hmac-sha2-256-96 hmac-sha1-96 hmac-ripemd160 hmac-ripemd160@openssh.com hmac-md5 none], algorithms(hmac: "hmac-md5-96", append_all_supported_algorithms: true)[:hmac]
     end
 
     def test_constructor_with_multiple_preferred_hmac_should_put_all_preferred_hmac_first
-      assert_equal %w[hmac-md5-96 hmac-sha1-96 hmac-sha2-512 hmac-sha2-256 hmac-sha1 hmac-sha2-512-96 hmac-sha2-256-96 hmac-ripemd160 hmac-ripemd160@openssh.com hmac-md5 none], algorithms(hmac: %w[hmac-md5-96 hmac-sha1-96], append_all_supported_algorithms: true)[:hmac]
+      assert_equal %w[hmac-md5-96 hmac-sha1-96 hmac-sha2-512-etm@openssh.com hmac-sha2-256-etm@openssh.com hmac-sha2-512 hmac-sha2-256 hmac-sha1 hmac-sha2-512-96 hmac-sha2-256-96 hmac-ripemd160 hmac-ripemd160@openssh.com hmac-md5 none], algorithms(hmac: %w[hmac-md5-96 hmac-sha1-96], append_all_supported_algorithms: true)[:hmac]
     end
 
     def test_constructor_with_unrecognized_hmac_should_ignore_those
-      assert_equal %w[hmac-sha2-512 hmac-sha2-256 hmac-sha1 hmac-sha2-512-96 hmac-sha2-256-96 hmac-sha1-96 hmac-ripemd160 hmac-ripemd160@openssh.com hmac-md5 hmac-md5-96 none],
+      assert_equal %w[hmac-sha2-512-etm@openssh.com hmac-sha2-256-etm@openssh.com hmac-sha2-512 hmac-sha2-256 hmac-sha1 hmac-sha2-512-96 hmac-sha2-256-96 hmac-sha1-96 hmac-ripemd160 hmac-ripemd160@openssh.com hmac-md5 hmac-md5-96 none],
         algorithms(hmac: "unknown hmac-md5-96", append_all_supported_algorithms: true)[:hmac]
     end
 
@@ -363,8 +363,8 @@ module Transport
       assert_equal options[:host_key] || (ed_ec_host_keys + %w[ssh-rsa-cert-v01@openssh.com ssh-rsa-cert-v00@openssh.com ssh-rsa]).join(','), buffer.read_string
       assert_equal options[:encryption_client] || 'aes256-ctr,aes192-ctr,aes128-ctr', buffer.read_string
       assert_equal options[:encryption_server] || 'aes256-ctr,aes192-ctr,aes128-ctr', buffer.read_string
-      assert_equal options[:hmac_client] || 'hmac-sha2-512,hmac-sha2-256,hmac-sha1', buffer.read_string
-      assert_equal options[:hmac_server] || 'hmac-sha2-512,hmac-sha2-256,hmac-sha1', buffer.read_string
+      assert_equal options[:hmac_client] || 'hmac-sha2-512-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512,hmac-sha2-256,hmac-sha1', buffer.read_string
+      assert_equal options[:hmac_server] || 'hmac-sha2-512-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512,hmac-sha2-256,hmac-sha1', buffer.read_string
       assert_equal options[:compression_client] || 'none,zlib@openssh.com,zlib', buffer.read_string
       assert_equal options[:compression_server] || 'none,zlib@openssh.com,zlib', buffer.read_string
       assert_equal options[:language_client] || '', buffer.read_string
diff --git a/test/transport/test_packet_stream.rb b/test/transport/test_packet_stream.rb
index 8f573e3..25c6b32 100644
--- a/test/transport/test_packet_stream.rb
+++ b/test/transport/test_packet_stream.rb
@@ -673,6 +673,14 @@ module Transport
         'hmac-sha2-512-96' => {
           false => "\003\352\031\261k\243\200\204\301\203]!\a\306\217\201\a[^\304\317\322\264\265~\361\017\n\205\272, #/\317\000\340I\274\363_\225U*",
           :standard => "\317\222v\316\234<\310\377\310\034\346\351\020:\025{\372PDS\246\344\312J\364\301\n\262\r<\037\231Mu\031\240\255\026\362\200Q\3112O\223\361\216\235\022\216\0162"
+        },
+        'hmac-sha2-256-etm@openssh.com' => {
+          false => "\x00\x00\x00\x18n\v\xF0\xD3\xCE,\xD5)\xEC\xE4\xA0\xCC\x9DK\x7F\x99\x03\xCE\x9E\x19\xBD\xFA\xED\x93|\xC0Y\x86\xE4\xA7\x91\x9B^\x97\x91\xBD\xEA+\xA2\x1FE\x7FK\xA2\f\xD2\x8A\x14\xD5\xB7\xD1\xF3\xE8\x95\xE7C",
+          :standard => "\x00\x00\x00 \xF51]F\xB2\x1E\xF8CM=\x85\xDC\x86w\xE0\x19s\x81\xF8\xBBT\x11\xC4\x81\x9A\xC5-tc\xE7\n\xC8\xA8l\xE5Y\t4\xFB\xD5\xCC\xF1\xF8\e\xE8\xC54\xDC\x84\xFC\e8pl\xD6\xF7\xF5_\xFA\xE9Cp\xC0P"
+        },
+        'hmac-sha2-512-etm@openssh.com' => {
+          false => "\x00\x00\x00\x18n\v\xF0\xD3\xCE,\xD5)\xEC\xE4\xA0\xCC\x9DK\x7F\x99\x03\xCE\x9E\x19\xBD\xFA\xED\x93[\x90|\xD8\e\xE1u\x9D1t\x91\e\xB6K\\WH\x97\xE4\x8F0\xED\xF6y\xA5(\x15a\xCB\xDA\xA0\x05\x8A)V\x8E\x9CLN\xA3\x95g7v($\x86l\xE691\xEB\xA5\xFC\x1EG\x91\xCA*\xD7\x01\xBE\xAA\"",
+          :standard => "\x00\x00\x00 \xF51]F\xB2\x1E\xF8CM=\x85\xDC\x86w\xE0\x19s\x81\xF8\xBBT\x11\xC4\x81\x9A\xC5-tc\xE7\n\xC8~;\x97\t\x83N|\xA8h8\xBD\x8F\xA9v<\"\xE1\xC5\xE0\x81)\xEC^\xD1\xC2\n&\xC4r\xA6\xCFPr\xC8VB\r\x01a\x98?\x97\xDB<\xCD{\xC2@\xA8%\xE1\xD9\xEE^{9\xACwL\e\x8D\x96s\xB7"
         }
       },
       'aes128-cbc' => {
@@ -691,6 +699,14 @@ module Transport
         'hmac-sha2-512-96' => {
           false => "\240\016\243k]0\330\253\030\320\334\261(\034E\211\230#\326\374\267\311O\211E(\234\325n\306NY#/\317\000\340I\274\363_\225U*",
           :standard => "\273\367\324\032\3762\334\026\r\246\342\022\016\325\024\270.\273\005\314\036\312\211\261\037A\361\362:W\316\352K\204\216b\2124>A\265g\331\177\233dK\251N\005f\275u\230\344xF\354+R"
+        },
+        'hmac-sha2-256-etm@openssh.com' => {
+          false => "\x00\x00\x00 \xA8\xD1\xBB\xFDLW\xC57k\x8B{\xE0^'\x8B\xB6s\x87\x87\xAE\x9D\xC0\x8B\x18H\xF2qe\xA4\xF06\xBF\xE7A\xEF\x8CJ\x14\xBB\xECC.\xF3\x98Rn\x9A$\xF9W\x16\xBC\xEE\xDDY{>\x1F\xE0$\xFCao<",
+          :standard => "\x00\x00\x00 )\x10,\x8C\x85\r\a\x02I\xE3\xAE\xF6\xA7+\xEC\x11\xF9\x8C\xB9\xAE\xAAe6\x9F\x9Cn\xF2\x7F\xA6\xE8\xE6\xDB`\xB3\xCD\xF6\"\x95\xEA\x9A\xAA9\xB8\x91&\xA0\xCCV\x87\x97\xE6cU\x03\xC0(\xEC6\x9F\t\xE9\xAB\x9Az"
+        },
+        'hmac-sha2-512-etm@openssh.com' => {
+          false => "\x00\x00\x00 \xA8\xD1\xBB\xFDLW\xC57k\x8B{\xE0^'\x8B\xB6s\x87\x87\xAE\x9D\xC0\x8B\x18H\xF2qe\xA4\xF06\xBFu\xCBV\xAE\xE41\xD2Z\xC3\x14)\xF3\x9E\x84R\xC5\x11\xB8zr\xF5\xDD\x87h\xD1\xA8>\xA1F*%W#\xAC|~\bQ\xA6\xF1\xAE\xD7\x807\xBE\xFCq\x1D\xA7\xDEw#\xC28w\x8E\xE3Q\x83}\xE5l\x1F\xD1",
+          :standard => "\x00\x00\x00 )\x10,\x8C\x85\r\a\x02I\xE3\xAE\xF6\xA7+\xEC\x11\xF9\x8C\xB9\xAE\xAAe6\x9F\x9Cn\xF2\x7F\xA6\xE8\xE6\xDB\xA7\xBB.\x93I5\xDF&\xD0\x98e\x8C\x87\xC7?\xD6|\x9C[\xFB\xE6\xE1T\t:\xC2w7\x16U\xD4V\x93N\xEDE\x03kGZ\xA4\xE9\xE42\xE5\x8E\x96\xDD\x9B*\xE0\x92L\x1A\xCE\x8D\xE9\xF7\xA1\xBC\xF0\xC9\xF2z"
         }
       },
       'aes192-cbc' => {
@@ -709,6 +725,14 @@ module Transport
         'hmac-sha2-512-96' => {
           false => "P$\377\302\326\262\276\215\206\343&\257#\315>Mp\232P\345o\215\330\213\t\027\300\360\300\037\267\003#/\317\000\340I\274\363_\225U*",
           :standard => "se\347\230\026\311\212\250yH\241\302n\364:\276\270M=H1\317\222^\362\237D\225N\354:\343\205M\006[\313$U/yZ\330\235\032\307\320DN\005f\275u\230\344xF\354+R"
+        },
+        'hmac-sha2-256-etm@openssh.com' => {
+          false => "\x00\x00\x00 \x9F\xB2\v\xB0\xEDq\xE0V\x04\xBAJ\xE3\f\x19EFRs\xB2r\xB3'>\xF0\x96\xC8\a\np\xDED~\xA1=mQ\xDF\xF4L\x9A\xF1\xF3%S\xB1\xE4\x03\x9D\x04^\x022O'W\x9E\xCFD\xFF\xF5u\xFF\x16\a",
+          :standard => "\x00\x00\x00 \xA5\x89\xA2\xF4\x85\xDD\xED\xC3=\x87\xAD\x81\x83~tV|\x90IH-\xA8\xF5$9\xE8Q\x88i\x9FL|u\xA1\x9F>[\xAA^\xF7L\xE9\x84\x94E\xC3\xD3\x9C\xB9\xB7.VsE\xD4\xA9\xB5\x924\xF4\xE4`\x00U"
+        },
+        'hmac-sha2-512-etm@openssh.com' => {
+          false => "\x00\x00\x00 \x9F\xB2\v\xB0\xEDq\xE0V\x04\xBAJ\xE3\f\x19EFRs\xB2r\xB3'>\xF0\x96\xC8\a\np\xDED~pp\b\x84F\x1A\xBE;\xE2\xAB4\vP$\xB6\xB5\xBAHDX\xE8\x81&G\xB5\xA3\xDA\xDC\v\x17\xC3\x99\xC5\xAD\xE6IR\xDC\x023\r\e)\xFDV\xB4\xCCV\xB5\x98\xB0$\xAB\xE0\x148\x8Ea\xF2x\x85\r\xDAv",
+          :standard => "\x00\x00\x00 \xA5\x89\xA2\xF4\x85\xDD\xED\xC3=\x87\xAD\x81\x83~tV|\x90IH-\xA8\xF5$9\xE8Q\x88i\x9FL|\xF7\xFE\x8C#HX\xD11\x81\xF8\x1Du\xD7;\xE0\a\xDB?\x002\xA9\xC2\x80\xC7m$[\x90vD\xB6\xCA\xD1\b\x11\xE0\xFE\xC7O\x9F\xCB\xB0\x97$\x92\xF2\x90\x8B$\xF3BM\x06B\xA4\xB1\x10L!\xD6*ud\x10"
         }
       },
       'aes256-cbc' => {
@@ -727,6 +751,14 @@ module Transport
         'hmac-sha2-512-96' => {
           false => "\266\001oG(\201s\255[\202j\031-\354\353]\022\374\367j2\257\b#\273r\275\341\232\264\255\340#/\317\000\340I\274\363_\225U*",
           :standard => "\251!O/_\253\321\217e\225\202\202W\261p\r\357\357\375\231\264Y,nZ/\366\225G\256\3000\036\223\237\353\265vG\231\215cvY\236%\315\365N\005f\275u\230\344xF\354+R"
+        },
+        'hmac-sha2-256-etm@openssh.com' => {
+          false => "\x00\x00\x00 \xDF'\xE2\xE7\xF6.\x92\x9F\xBA)N\xFE\xA0\xCC\x9A\x9Ai{\xB5\r\f\x18\xFA\xA9\x89\x9B\xD3\xF0zXK^\xFF\xB9\x14\xF1?\x0Ez\xF5\x8A\t~x\xCC\xFFj\x15\xE8\"\xA1dUd\xA4\xA5?\xF0\x1E\xE9\x82\xE2R\a",
+          :standard => "\x00\x00\x00 1\xFC\xCAD\x0E\x97\x7F\xC51\xB0\b\xE1\xE7\xAC\x90\x9E\xCD\xB2\x88\x84d*\xD5E\xE1\x15\xC9\xBE\xCB\x8D\x14^\x9A\xC4v\xAA\xA7\x19L\x0E\xCBX;\xEDh\xDC\xCD\xD0\xB4#>\x8B\x7F\xB6\x97U\x84\x9CB\x84\xB1]\x1Co"
+        },
+        'hmac-sha2-512-etm@openssh.com' => {
+          false => "\x00\x00\x00 \xDF'\xE2\xE7\xF6.\x92\x9F\xBA)N\xFE\xA0\xCC\x9A\x9Ai{\xB5\r\f\x18\xFA\xA9\x89\x9B\xD3\xF0zXK^>\xE2\xDE\x95]\xD4\f%gBo3\x95\xD7\xFBF\xD8\xC5\x18R\x10\xB0\xA6i\xB8\ej\xAA}?\xF8\xA7\xB2K\x9E\xE3\b\xA5.D\x94\x04,\xB1\xFA\x92\xAA\xA9`\x95\x19\xC7P\x92r<\xCB\x93\xD9\xD8Nu\x89\b",
+          :standard => "\x00\x00\x00 1\xFC\xCAD\x0E\x97\x7F\xC51\xB0\b\xE1\xE7\xAC\x90\x9E\xCD\xB2\x88\x84d*\xD5E\xE1\x15\xC9\xBE\xCB\x8D\x14^\xF8\xD2x\x817\x7F#b\xEC\x96\xB9\xE2pG\x9BI\bQ\xC0\xA8\xB6$\xA8]\x05?e\xE5\x86S\x0Fw\xA4Q\xAFW\xFE>\x9B7:\eF\n\xDF\xB1\x85M\xA5N\xCC^\xC9\xA6\xCDp\xBA\x13>\xB9\xEB~\x87\xEB"
         }
       },
       'blowfish-cbc' => {
@@ -745,6 +777,14 @@ module Transport
         'hmac-sha2-512-96' => {
           false => "vT\353\203\247\206L\255e\371\001 6B/\234g\332\371\224l\227\257\346\373E\237C2\212u)#/\317\000\340I\274\363_\225U*",
           :standard => "U\257\231e\347\274\bh\016X\232h\334\v\005\316e1G$-\367##\256$rW\000\210\335_\360\f\000\205#\370\201\006Q\3112O\223\361\216\235\022\216\0162"
+        },
+        'hmac-sha2-256-etm@openssh.com' => {
+          false => "\x00\x00\x00\x18\x86\xB4\xFC\xB0\x1F\x93\xFB\xFF\xF6P\xF9ro\xF7\xB8\x87~l)q\x04dK&I\xFC\xEBQ\xC8\xFCO\"\x8D\x87\x98i\x92\xA7\xD8\xC9L\xE4Q\x91\xC6u\xA8\x06\xBEJK\xAEc&C\xFD",
+          :standard => "\x00\x00\x00 \xCA@\xF0\xE1\xADdf|\v\x0E\xEEt\xE7\xCD!\x90c\xA5\xCDE\x81\xD0\xBC\xDC7\xF8Y\xA0\xE7^\x1E\xDA.\x9F=\x8A\xB7\xC5%u\xEF\n\xB6F\xCBw\xA30s>cDl\x1AP\x18I[\xFC<=\xCBm\xAF"
+        },
+        'hmac-sha2-512-etm@openssh.com' => {
+          false => "\x00\x00\x00\x18\x86\xB4\xFC\xB0\x1F\x93\xFB\xFF\xF6P\xF9ro\xF7\xB8\x87~l)q\x04dK&\x84\xC75!\xB9\x04gt\xD8\xF7]\x82\xC9\x93EvP4\xF1*\x19C3\xFBD_!\x1F\f\xE3#9\xA2\xA2\xB6P\xE4\x89\xAB\x89|kK$\xCE\x18\\F\x90\xB3\x88\x83\xA9\\\x9C\x86\x87E\xA3\x8BX\xEB%7",
+          :standard => "\x00\x00\x00 \xCA@\xF0\xE1\xADdf|\v\x0E\xEEt\xE7\xCD!\x90c\xA5\xCDE\x81\xD0\xBC\xDC7\xF8Y\xA0\xE7^\x1E\xDA$\xE3\xEA|\x7F\"zF\x92\e%\x0EpYI\t\xA8R\xA1\x15\xB9\xA8\xA4\x91\xAA\x9CD>\x8B\xE8\xA2\xC9\x85\x00\x94\xDE\xBD\x9C\x8E+\x98\xEE\x91\x9Eb\xFE\x15\xD0X\xD8\xD0=\xF7j\x9C@\xAC_\x94[\x8D,7\f"
         }
       },
       'cast128-cbc' => {
@@ -763,6 +803,14 @@ module Transport
         'hmac-sha2-512-96' => {
           false => "\361\026\313!\31235|w~\n\261\257\277\e\277b\246b\342\333\eE\021N\345\343m\314\272\315\376#/\317\000\340I\274\363_\225U*",
           :standard => "\375i\253\004\311E\2011)\220$\251A\245\f(\371\263\314\242\353\260\272\367\276\"\031\224$\244\311W\307Oe\224\0017\336\325Q\3112O\223\361\216\235\022\216\0162"
+        },
+        'hmac-sha2-256-etm@openssh.com' => {
+          false => "\x00\x00\x00\x18\xC1`!\xB4q\x13\xBD\x8B\xA7x\xD4\x9A\x85\xE9;#\x7FX\xA2`\x939\xE8\x8B{s\xB7Kwo\x19\"\xB8\xAD\xA1\xB1k\xB6\x00\xFAc\xF9\xC4\x0E\xC0\xAF*m\bOW\xE9=\xD4\xF3\xB4",
+          :standard => "\x00\x00\x00 \x98\x80\xFA\xB7'\x90\x9D'\xAE\x95s[\xDA,}\xACdpu[\xB1$\x8C\x8Cu<}k`\x84\xEE\xA6A\xD2qGow\xCE\x1F\x16c\xF1qx\xA4\x97\x03K\x93\xC86\xD6?\"k\xAD\xCD\x8D\xA9\x8E\xBFAZ"
+        },
+        'hmac-sha2-512-etm@openssh.com' => {
+          false => "\x00\x00\x00\x18\xC1`!\xB4q\x13\xBD\x8B\xA7x\xD4\x9A\x85\xE9;#\x7FX\xA2`\x939\xE8\x8B\xDF\xF7\xF4\xD3\x9E\xC3\"\xAD\xB2\xD6&*\x03.#\x1A\xB1s\x8E\x18I\x0F\x83*\xE8.#\xDE\x19\xFF \xCF\x9C\xFE&\xDDQ\xEA\xFD\x12\x8A\f\xE9\xD6\xF1\xDA}\x16\xE5\xEF\x10\xD4B\f\v@1\x04\xA5&r\xB03\xC0",
+          :standard => "\x00\x00\x00 \x98\x80\xFA\xB7'\x90\x9D'\xAE\x95s[\xDA,}\xACdpu[\xB1$\x8C\x8Cu<}k`\x84\xEE\xA6\xF8P`\x00m\x93\x1Dz\xDD\xA3\xAE\xD4>\xC3y\xD6\x86\x00Osv\x02z\xFE\xE6\xD5\x85\x80\x02<\x8F_8B\xD0\x89\xA1[\xFE\xA8qX\xFE)\xDAf\xA7\x8A\xE5\xF7\xECCY$!s\xD9!\xA7\xDB\x84\x8Fq\x8F"
         }
       },
       'idea-cbc' => {
@@ -781,6 +829,14 @@ module Transport
         'hmac-sha2-512-96' => {
           false => "\342\255\202$\273\201\025#\245\2341F\263\005@{\000<\266&s\016\251NH=J\322/\220 H#/\317\000\340I\274\363_\225U*",
           :standard => "F\3048\360\357\265\215I\021)\a\254/\315%\354M\004\330\006\356\vFr\250K\225\223x\277+Q)\022\327\311K\025\322\317Q\3112O\223\361\216\235\022\216\0162"
+        },
+        'hmac-sha2-256-etm@openssh.com' => {
+          false => "\x00\x00\x00\x18\xD3~\x94JDl\x94\xBBN6\x922^YN{j\x04r\xE6\x96UCzn\xD6\x0E\x80\xA9\xB9\x06\xB8\xCD\x18\x1A\x17\xAA\xB5\xDFV_\x96\x981\xD4 \x97\x043|\xFB6\x84Yz\xC3",
+          :standard => "\x00\x00\x00 \xBATT\xEC\xA5k\xF2\xCA\x8Fp\xE3\xF2\xB8Qtm\x82\x86Z\xFB\x95V\x1CWo\x89\x1D\b\xB0\xCA\x8FS\xBE\xFA\\\x01\x7F\x82\xFE\xBC\xD3G\x88J@\f\xF6\xC2\xA0\a\xCA\xACuQ\x8A \x87c\xABMO\xF5\xD0\""
+        },
+        'hmac-sha2-512-etm@openssh.com' => {
+          false => "\x00\x00\x00\x18\xD3~\x94JDl\x94\xBBN6\x922^YN{j\x04r\xE6\x96UCz^\xED\x8E\x949=\xD7\xB4\x8C\n]\x1DY\xF9He\x8C\xC4$\xB2\xE2\xBB\x8F\xDA\xC6\x14\\\xCCe\xB9\xA3\x10\xB6n\x9Cl\xC5/e\xEBP#_\bAP\xD3\xA5Y{#\xCC0g\x96J\x87)\x17\xBB\xBC\x8B=\f",
+          :standard => "\x00\x00\x00 \xBATT\xEC\xA5k\xF2\xCA\x8Fp\xE3\xF2\xB8Qtm\x82\x86Z\xFB\x95V\x1CWo\x89\x1D\b\xB0\xCA\x8FS\x8Bi\xE5\xDB\x16\x9F[N\f\xEB\x96k\x1C\xA5{\x9F\xFB\xB1$\xEA\xF0\x7F\xA5\xA7\x99(3\xFC+\xD2%\xB7\a\xEEu\x97\xF9\x98x\xB5\xFF\"I\xBEo\t\xCE?\xF5f^\x87\"?\x18\x89$\xF8\xB0j\xEBnO\x15"
         }
       },
       '3des-ctr' => {
@@ -799,6 +855,14 @@ module Transport
         'hmac-sha2-512-96' => {
           false => "\xED#\x86\xD5\xE1mP\v\f\xB9\xC1\xE6\xFD\xA0~,\xD3\x13\x12\x8Cp\xD4F\x92\xCB\xB6R>\xFA]\x9B\xB1#/\xCF\x00\xE0I\xBC\xF3_\x95U*",
           :standard => "\xED#\x86\xED\xE0\x11\xCDim\xDD\xA8\xE2x\x8EB\x06\x9E73$\xBC\x9FA\xE0\xDB\xAE\x11Y\xAD\xED\xD43\x86N\x89\xFE\x14V\x91BQ\xC92O\x93\xF1\x8E\x9D\x12\x8E\x0E2"
+        },
+        'hmac-sha2-256-etm@openssh.com' => {
+          false => "\x00\x00\x00\x18\xE9'\x87\xC9\xE9iXoi\xDB\xBD\xE5\xFF\xABe,\xB4z|\xEBx\xCC\x05\xF5\xF9\xB7t\x87\x9Frz\x81\x91\x91\xB4\x96j\x92NA1\x85\xDATA\xB4\xA0W\xBDI\xE4$\xCDh&\t",
+          :standard => "\x00\x00\x00 \xE8[\x1A\xAB\x88\r1k\xEC\xF5\x81\xCF\xB2\x8FD\x84x1{\x99h\xD4F\x92\xC3Q\xEEQ\xB5QLl\xFBU\xEE\xC3s\xBEoG\xBC\xC9\xF4\xA2\x86\xE7G\xAF\x18n5\xB1\xBD.\xC3\x82\xA3QC\xBC99%."
+        },
+        'hmac-sha2-512-etm@openssh.com' => {
+          false => "\x00\x00\x00\x18\xE9'\x87\xC9\xE9iXoi\xDB\xBD\xE5\xFF\xABe,\xB4z|\xEBx\xCC\x05\xF5\x80\xA28\x81L\xDE0\xF9\xB6+'\x1D\xAD\xA7i\xE3\xB9\xDD\x04f\x05\xB5~\xBD\xF0\xDD\xF0\xDB2:_-\xB2\xCC\xA8}O\x0Ey\xF7\x93\x00\xBE\xF2\xA0\xA3^`\xE4\xEAd\xF9;\x99\aq\xBD\xBB\xA5\xA4'\xF4\x8E\x1A",
+          :standard => "\x00\x00\x00 \xE8[\x1A\xAB\x88\r1k\xEC\xF5\x81\xCF\xB2\x8FD\x84x1{\x99h\xD4F\x92\xC3Q\xEEQ\xB5QLl\x99\xD1{#`wQDr\x91\xB4\xCD>9\x8C~\xB9\x02=g\xC3\x04\x00\xF4\e\"\x8C\x9EM\xEA\xB3\x91 N\x87bN\xAA\xE9W\n\xA4Y\x8AU\x9D\xB9\x0F\xF0\xB6\x197\xDF5!\x92W\x9B\xAC\xA2k\xD5\xAFk"
         }
       },
       'blowfish-ctr' => {
@@ -817,6 +881,14 @@ module Transport
         'hmac-sha2-512-96' => {
           false => "\xF7gk6\xB8\xACK\x1D\xC4Ls\xB0{\x0F\xC7\xC4M\xC5>\xF6G8\xD4\xBCu\x152FoJ\xB0\xC0#/\xCF\x00\xE0I\xBC\xF3_\x95U*",
           :standard => "\xF7gk\x0E\xB9\xD0\xD6\x7F\xA5(\x1A\xB4\xFE!\xFB\xEE\x00\xE1\x1F^\x8Bs\xD3\xCEe\rq!8\xFA\xFFB\r\xE9\xFC\xF6\xCA\xBC\x03\xA9Q\xC92O\x93\xF1\x8E\x9D\x12\x8E\x0E2"
+        },
+        'hmac-sha2-256-etm@openssh.com' => {
+          false => "\x00\x00\x00\x18\xF3cj*\xB0\xA8Cy\xA1.\x0F\xB3y\x04\xDC\xC4*\xACP\x91O \x97\xDB\xEA\xD57~3;\xEB\xCD\xB6\xCDV\xEEp\x93\xF5\v\xB1T\xA6\xD2L=71L]\xE2\xDA\xE0G2\x05",
+          :standard => "\x00\x00\x00 \xF2\x1F\xF7H\xD1\xCC*}$\x003\x994 \xFDl\xE6\xE7W\xE3_8\xD4\xBC}\xF2\x8E) Fg\x1D\xAAZ^[\xEF\x17\x1A2\xAAY\xEB\xB0F\x8F Z1Ung\xB7\xBC.\xA2\xE2\x8A\xC1\x17h\xC1\x17\xF2"
+        },
+        'hmac-sha2-512-etm@openssh.com' => {
+          false => "\x00\x00\x00\x18\xF3cj*\xB0\xA8Cy\xA1.\x0F\xB3y\x04\xDC\xC4*\xACP\x91O \x97\xDBI\xF9\xEC\xD5\x92\xA4([\xA3\x12:\x1E\x8B_q\x81\x89\xB1\xE1\x13B\xB1\xD1A,\xCA\xFF\xC1\x99\f\xEC\xA0T\xC4\xAE\x1Ed\x0F{B\x85\xD4\xD8\xAA-0\xF6{\xC1\x9C\x95qo+\xA1\x90 `;\xADL\xC5]@",
+          :standard => "\x00\x00\x00 \xF2\x1F\xF7H\xD1\xCC*}$\x003\x994 \xFDl\xE6\xE7W\xE3_8\xD4\xBC}\xF2\x8E) Fg\x1D\xF4\xCEUk\a\xF8\xA2V\xFD]\xA98W)\x86\xC6\xAF\xEB\xBB\xBF\xB2\xF8\xF7u\xAD\x90\xB5P\xAA\x195\x93:\x85\xAB1\xD5d9\x99\xD6\xE8\\V\xCC*q\xDB\xD5\x7F|`\x10\xE9yR\x82-\xDA\xE4\xE0K%\x87"
         }
       },
       'aes128-ctr' => {
@@ -835,6 +907,14 @@ module Transport
         'hmac-sha2-512-96' => {
           false => "\xD6\x98\xC1n+6\xCA`s2\x06\xAA\x80\xFA\xF3\xF6\xCA\xF9\xC8[BB\xDC\x9F\xDC$\x88*\xA7\x00\x8E\xFD#/\xCF\x00\xE0I\xBC\xF3_\x95U*",
           :standard => "\xD6\x98\xC1^2JW\x02\x12Vo\xAE\x05\xD4\xCF\xDC\x87\xDD\xE9\xF3\x8E\t\xDB\xED\xCC<\xCBM\xF0\xB0\xC1\x7F\xD7\x17\x931\xBC~\r\xF2\x87\xB89\x9B\x8B\xB3\x8E\x15N\x05f\xBDu\x98\xE4xF\xEC+R"
+        },
+        'hmac-sha2-256-etm@openssh.com' => {
+          false => "\x00\x00\x00 \xDA\x9C\xC0r#2\xC2\x04\x16Pz\xA9\x82\xF1\xE8\xF6\xAD\x90\xA6<JZ\x9F\xF8\x83s{\xC7\xAE\xFB\\B\xCC\xFAD\x95\xC7L\xF1\xB5j)\x06B\xE1\x0F\xEA\x97\x95 <\r1#\x83#\xF8!\xFE\xE9~\x16\xA31",
+          :standard => "\x00\x00\x00 \xD3\xE0]\x10BV\xAB\x00\x93~F\x83\xCF\xD5\xC9^a\xDB\xA1NZB\xDC\x9F\xD4\xC34E\xE8\fY \x91\x80\xE49I`\xE6\xED\x96\xA2C\x01\xF5\xB7{\t<\x88d\xDC/#O\x9B\xC2v\x955\x1F\x1D\x8A\x0F"
+        },
+        'hmac-sha2-512-etm@openssh.com' => {
+          false => "\x00\x00\x00 \xDA\x9C\xC0r#2\xC2\x04\x16Pz\xA9\x82\xF1\xE8\xF6\xAD\x90\xA6<JZ\x9F\xF8\x83s{\xC7\xAE\xFB\\B\xD0\xC5k\x1Ad\x979\xDE\xD1SP\xFD\x03\xAF4\xE3\x7F4JY{\x947\x82\xB4\x86h\xAF\xCE/\xA7m\xEE\x8D\xADZ\b\x1A'g\xE2\t\x15\x9E=\x81\xFFSH\xA4\xBC\xA5\xD6\xCF\x9C\xFB@F\xC6\xEB\xDBN\xC7\x82",
+          :standard => "\x00\x00\x00 \xD3\xE0]\x10BV\xAB\x00\x93~F\x83\xCF\xD5\xC9^a\xDB\xA1NZB\xDC\x9F\xD4\xC34E\xE8\fY \xCEl\xF3\x95u\xF9\xD2\x17\x83\x98\xC6Q\x91S?\e^\xF6q\xA0M\x92S'\xD7\x1D\x84\x0E]\x82\x8F!U\x85S\xD2*\xB7\xC5\xBD\x00j\xC2@W\x82\xC9\x14\x95c\a\x99\xC6\xA9\xA0q\xD9\xCA\x87\x01zg\x18\v"
         }
       },
       'aes192-ctr' => {
@@ -853,6 +933,14 @@ module Transport
         'hmac-sha2-512-96' => {
           false => "\xA8\x02\xB4-\xFBYo4F\"\xCF\xB8\x92\xF08\xAC\xE8\xECk\xECO\xE7\xF8\x01\xF8\xB0\x9E\x05\xFB\xA7\xA7\x91#/\xCF\x00\xE0I\xBC\xF3_\x95U*",
           :standard => "\xA8\x02\xB4\x1D\xE2%\xF2V'F\xA6\xBC\x17\xDE\x04\x86\xA5\xC8JD\x83\xAC\xFFs\xE8\xA8\xDDb\xAC\x17\xE8\x13\x92V\x9E\x00!\x1F\xD4\x00\x92T\x15\xDE\xA4\xCA\xE9\xC1N\x05f\xBDu\x98\xE4xF\xEC+R"
+        },
+        'hmac-sha2-256-etm@openssh.com' => {
+          false => "\x00\x00\x00 \xA4\x06\xB51\xF3]gP\#@\xB3\xBB\x90\xFB#\xAC\x8F\x85\x05\x8BG\xFF\xBBf\xA7\xE7m\xE8\xF2\\u.l0\x91c\x82\xD9}7\x13\xE1\xAF \xB5\xE8 \xA5\xA5\x1E\x7Fe\x13\x8A\xCEdo\x1A\x10)\xA0\x9DO\xBB",
+          :standard => "\x00\x00\x00 \xADz(S\x929\x0ET\xA6n\x8F\x91\xDD\xDF\x02\x04C\xCE\x02\xF9W\xE7\xF8\x01\xF0W\"j\xB4\xABpL\xFB\xEFi?y^&\xBF\xF0#\xDD}\xBFU\xE7\xAA\x83y\xA7M\xAFMJm\xD2\x81\x1C\x9C;\xC0]\x89"
+        },
+        'hmac-sha2-512-etm@openssh.com' => {
+          false => "\x00\x00\x00 \xA4\x06\xB51\xF3]gP\#@\xB3\xBB\x90\xFB#\xAC\x8F\x85\x05\x8BG\xFF\xBBf\xA7\xE7m\xE8\xF2\\u.@\xBDZq\xDDG\xF3\xEC\x9A,~9\xC9m\x19\xAE7\xBB\xAA\\\n\xAE\xCFn)0\xC6n\xA2\xC6\xB2\xD5\xD0N\n\xDDl\xE5\xA0\xE2A\x89\x1F#'\r\xA5\x81t\x81Z\eF\x8E\xEASO\xFE/\xA3\x9A4{\xDF",
+          :standard => "\x00\x00\x00 \xADz(S\x929\x0ET\xA6n\x8F\x91\xDD\xDF\x02\x04C\xCE\x02\xF9W\xE7\xF8\x01\xF0W\"j\xB4\xABpLk;\x02(UdO\xBE`\x1F\x9D\xFD=\xE7\xD2\xEF\x80\xD3FC\xDF\xCA\xDD>r\x0Ev'\xFE9AK\xA3(\x0FT\n\x19M\\\xD8\xA1\x88\x87+^\x92\xC2\xF1\x94\xBB\xFD:\x04dC\xAE\x1E\xD5'jP\xE6\x17"
         }
       },
       'aes256-ctr' => {
@@ -871,6 +959,14 @@ module Transport
         'hmac-sha2-512-96' => {
           false => "M\x1DcA\r]\\\x95?&\xE3D[\xCC1\x9B\xE0\xAF\x96\xA8\x86Y\xBD\x16\xE5xR%u\xC9(\r#/\xCF\x00\xE0I\xBC\xF3_\x95U*",
           :standard => "M\x1Dcq\x14!\xC1\xF7^B\x8A@\xDE\xE2\r\xB1\xAD\x8B\xB7\x00J\x12\xBAd\xF5`\x11B\"yg\x8F\x9F\xAB\xC8 d\xB4\xE7^w\xC4\x89\a\x17\x15\x82\nN\x05f\xBDu\x98\xE4xF\xEC+R"
+        },
+        'hmac-sha2-256-etm@openssh.com' => {
+          false => "\x00\x00\x00 A\x19b]\x05YT\xF1ZD\x9FGY\xC7*\x9B\x87\xC6\xF8\xCF\x8EA\xFEq\xBA/\xA1\xC8|2\xFA\xB2\xB1W\xD4\xA8\xEF\xC8~/>?\xF7f!(\x1C\xB7\x1C\x9C\xA9\xC2\xE4\xEF\x88k\e\x8A\xC4/QM\x84E",
+          :standard => "\x00\x00\x00 He\xFF?d==\xF5\xDFj\xA3m\x14\xE3\v3K\x8D\xFF\xBD\x9EY\xBD\x16\xED\x9F\xEEJ:\xC5\xFF\xD0\x81\xFC\xA4\x87\xF3\x06x\xFE\xCDV*%\x13\xAA|\xA8\xE3\xB8^`vl\xFF\x02\xF9\xEC\x02\x8A\xFFt\xFC\x03"
+        },
+        'hmac-sha2-512-etm@openssh.com' => {
+          false => "\x00\x00\x00 A\x19b]\x05YT\xF1ZD\x9FGY\xC7*\x9B\x87\xC6\xF8\xCF\x8EA\xFEq\xBA/\xA1\xC8|2\xFA\xB2\x86x\r\x88Q-B\x03\xD5\x14\x8D\x98\xA3}&\x98va\xD9UZs\x82|\xDA{\xAD\x96\x88\x05%s\xB4*_\xBFWR\a\x90\xD9P\x81IY\xAE\x88|\x88\xC1k\x16\xDF\xDFPA\xBB\x13Dk\x84\xBBe1",
+          :standard => "\x00\x00\x00 He\xFF?d==\xF5\xDFj\xA3m\x14\xE3\v3K\x8D\xFF\xBD\x9EY\xBD\x16\xED\x9F\xEEJ:\xC5\xFF\xD0\xB4\xAE\x8A\x86\xE6\xAE\xF3\xD8\xD8\xB2\x1Dazu$\x01nc\aYh\xBA\x15\x83\xE20\x900\\mX\x96\xF22\xEBJa\x96>\xED\x0E\x17`m\e\x97@\xF7Y+\xC8\x98\v\x17I\xC4\x86s\xCF\xB4j\xDEV0"
         }
       },
       'cast128-ctr' => {
@@ -889,6 +985,14 @@ module Transport
         'hmac-sha2-512-96' => {
           false => "\x10\xA0cJ6W\xC9\xC7\x02\xF8\xCD\xE31\xF9\xE7n\x0Fj\x7F\x99\x8A\f\x84\x80\x80\xE8p\x9C\x14\x83\x1C\xC7#/\xCF\x00\xE0I\xBC\xF3_\x95U*",
           :standard => "\x10\xA0cr7+T\xA5c\x9C\xA4\xE7\xB4\xD7\xDBDBN^1FG\x83\xF2\x90\xF03\xFBC3SE\xF7x;q\x89\xA80\xEAQ\xC92O\x93\xF1\x8E\x9D\x12\x8E\x0E2"
+        },
+        'hmac-sha2-256-etm@openssh.com' => {
+          false => "\x00\x00\x00\x18\x14\xA4bV>S\xC1\xA3g\x9A\xB1\xE03\xF2\xFCnh\x03\x11\xFE\x82\x14\xC7\xE7\xF3E\x16\e\xF9\x9FH;\x83\xF5G\xAA\xCE\x94\x1C\x19\xB9\x12\xC0\xB4\xBB\xC6\xA1A\xE8\xFA\x03[\x8D<\xEB\xBE",
+          :standard => "\x00\x00\x00 \x15\xD8\xFF4_7\xA8\xA7\xE2\xB4\x8D\xCA~\xD6\xDD\xC6\xA4H\x16\x8C\x92\f\x84\x80\x88\x0F\xCC\xF3[\x8F\xCB\x1A\xD2Q\xA8\xA0\x990tw\x89*\xB4\xA1\xB9\x9A\xF2\xBD9v\"st\xB7:S5o\xD0\xA1\xD5\xA5\xC3\x83"
+        },
+        'hmac-sha2-512-etm@openssh.com' => {
+          false => "\x00\x00\x00\x18\x14\xA4bV>S\xC1\xA3g\x9A\xB1\xE03\xF2\xFCnh\x03\x11\xFE\x82\x14\xC7\xE7U\f\xDF\xD4(\xEE\xEE\xEE\x1D%\xDC\xE9n\xA6C\xB7\xB8!K\x90\xD2%\r\xB7\xAA\t\xE1\xA5\x12#\x93\x95m\xD8GY\xF4\xC9\xCC\xF8\x19(6\xD5\xE3\x8F.\xC9\xBFE\xAF\x8C\xF2\xA9\xD96v[zf\x02CI`",
+          :standard => "\x00\x00\x00 \x15\xD8\xFF4_7\xA8\xA7\xE2\xB4\x8D\xCA~\xD6\xDD\xC6\xA4H\x16\x8C\x92\f\x84\x80\x88\x0F\xCC\xF3[\x8F\xCB\x1A\xE9\xC8\xAC\x85n\xDE\xF6H\xF0\xFAE_\xE43I\xCE\xC0\x8A\xC2\xD0+o\x1E\xFB\xCF\xFC\x8E\tI\xFFLlV\xEAP\xE8h\xEF\xF0p!p\x83B'\xFA\xF7wk\xA0\xD4\xB9x\xC6h\xAC\xD9\x94\xC1\x0E\xD44.\xFB"
         }
       },
       'none' => {
@@ -907,6 +1011,14 @@ module Transport
         'hmac-sha2-512-96' => {
           false => "\000\000\000\034\b\004\001\000\000\000\tdebugging\000\000\000\000\b\030CgWO\260\212#/\317\000\340I\274\363_\225U*",
           :standard => "\000\000\000$\tx\234bad``\340LIM*MO\317\314K\ar\030\000\000\000\000\377\377\b\030CgWO\260\212^Q\3112O\223\361\216\235\022\216\0162"
+        },
+        'hmac-sha2-256-etm@openssh.com' => {
+          false => "\x00\x00\x00\x18\x04\x04\x01\x00\x00\x00\tdebugging\x00\x00\x00\x00\b\x18Cg:\xCA\xDDb\x1D\xA9'?\xBB\xB1\x86\xBB\x98\xD3\x1E4\xDA;\x93\xDF\xBFz\x8D\x98\xDF\xFB PZ\xD9o\xF8",
+          :standard => "\x00\x00\x00 \x05x\x9Cbad``\xE0LIM*MO\xCF\xCCK\ar\x18\x00\x00\x00\x00\xFF\xFF\b\x18CgW\x80-\xA99B\x81\xFE\xF2\v*\x00\xF7\xB3o\xBCQ\xAEWj\xC9\x14\x197-8tk/\x9E\xAF\x00\xAB"
+        },
+        'hmac-sha2-512-etm@openssh.com' => {
+          false => "\x00\x00\x00\x18\x04\x04\x01\x00\x00\x00\tdebugging\x00\x00\x00\x00\b\x18Cg\x8D\x98\x9D\xCA`\xC7\x13| \xBE\xC4@N\xCE\x15\xD8\x0E\x03\xE3\xEC\x1AB\xD7\xC0\xA2j=\x8C\x17\xFA,\xAEY\xDD\xF7\xDC\bNTX\xEF\xF1\x80\x1A\x81h\xC7:\xDD\x9B\xC7R\xB4\x93\xA8#\x967f\xF7\xE0\x84\xCF\x9F",
+          :standard => "\x00\x00\x00 \x05x\x9Cbad``\xE0LIM*MO\xCF\xCCK\ar\x18\x00\x00\x00\x00\xFF\xFF\b\x18CgW\xBADS\xA9\xF0I\x91\xFF< /\x1E\e\xC4v\x9B\x11\x9E\xEFiW[*d\xA26\xEA\xFB\xD5*\xC8\x9B\x9A\xAC.h:\xED\xA8R\xAD\xFC\x85@\xC3\x89\x8E,\x01*O\xF2\xFE\r\xCF\xA4\xA5\xAB\x03k\xC8\x9E])"
         }
       },
       'rijndael-cbc@lysator.liu.se' => {
@@ -925,6 +1037,14 @@ module Transport
         'hmac-sha2-512-96' => {
           false => "\266\001oG(\201s\255[\202j\031-\354\353]\022\374\367j2\257\b#\273r\275\341\232\264\255\340#/\317\000\340I\274\363_\225U*",
           :standard => "\251!O/_\253\321\217e\225\202\202W\261p\r\357\357\375\231\264Y,nZ/\366\225G\256\3000\036\223\237\353\265vG\231\215cvY\236%\315\365N\005f\275u\230\344xF\354+R"
+        },
+        'hmac-sha2-256-etm@openssh.com' => {
+          false => "\x00\x00\x00 \xDF'\xE2\xE7\xF6.\x92\x9F\xBA)N\xFE\xA0\xCC\x9A\x9Ai{\xB5\r\f\x18\xFA\xA9\x89\x9B\xD3\xF0zXK^\xFF\xB9\x14\xF1?\x0Ez\xF5\x8A\t~x\xCC\xFFj\x15\xE8\"\xA1dUd\xA4\xA5?\xF0\x1E\xE9\x82\xE2R\a",
+          :standard => "\x00\x00\x00 1\xFC\xCAD\x0E\x97\x7F\xC51\xB0\b\xE1\xE7\xAC\x90\x9E\xCD\xB2\x88\x84d*\xD5E\xE1\x15\xC9\xBE\xCB\x8D\x14^\x9A\xC4v\xAA\xA7\x19L\x0E\xCBX;\xEDh\xDC\xCD\xD0\xB4#>\x8B\x7F\xB6\x97U\x84\x9CB\x84\xB1]\x1Co"
+        },
+        'hmac-sha2-512-etm@openssh.com' => {
+          false => "\x00\x00\x00 \xDF'\xE2\xE7\xF6.\x92\x9F\xBA)N\xFE\xA0\xCC\x9A\x9Ai{\xB5\r\f\x18\xFA\xA9\x89\x9B\xD3\xF0zXK^>\xE2\xDE\x95]\xD4\f%gBo3\x95\xD7\xFBF\xD8\xC5\x18R\x10\xB0\xA6i\xB8\ej\xAA}?\xF8\xA7\xB2K\x9E\xE3\b\xA5.D\x94\x04,\xB1\xFA\x92\xAA\xA9`\x95\x19\xC7P\x92r<\xCB\x93\xD9\xD8Nu\x89\b",
+          :standard => "\x00\x00\x00 1\xFC\xCAD\x0E\x97\x7F\xC51\xB0\b\xE1\xE7\xAC\x90\x9E\xCD\xB2\x88\x84d*\xD5E\xE1\x15\xC9\xBE\xCB\x8D\x14^\xF8\xD2x\x817\x7F#b\xEC\x96\xB9\xE2pG\x9BI\bQ\xC0\xA8\xB6$\xA8]\x05?e\xE5\x86S\x0Fw\xA4Q\xAFW\xFE>\x9B7:\eF\n\xDF\xB1\x85M\xA5N\xCC^\xC9\xA6\xCDp\xBA\x13>\xB9\xEB~\x87\xEB"
         }
       }
     }