diff --git a/tools/releasetools/Android.bp b/tools/releasetools/Android.bp
index 5f99f6c..ee266b7 100644
--- a/tools/releasetools/Android.bp
+++ b/tools/releasetools/Android.bp
@@ -168,6 +168,7 @@
         "apexd_host",
         "brillo_update_payload",
         "checkvintf",
+        "generate_gki_certificate",
         "lz4",
         "toybox",
         "unpack_bootimg",
@@ -244,6 +245,7 @@
         "boot_signer",
         "brotli",
         "bsdiff",
+        "generate_gki_certificate",
         "imgdiff",
         "lz4",
         "mkbootfs",
@@ -308,6 +310,7 @@
         "brotli",
         "bsdiff",
         "deapexer",
+        "generate_gki_certificate",
         "imgdiff",
         "lz4",
         "mkbootfs",
diff --git a/tools/releasetools/common.py b/tools/releasetools/common.py
index a4c92ae..8ce6083 100644
--- a/tools/releasetools/common.py
+++ b/tools/releasetools/common.py
@@ -1575,6 +1575,50 @@
       pubkey_path=pubkey_path)
 
 
+def _HasGkiCertificationArgs():
+  return ("gki_signing_key_path" in OPTIONS.info_dict and
+          "gki_signing_algorithm" in OPTIONS.info_dict)
+
+
+def _GenerateGkiCertificate(image, image_name):
+  key_path = OPTIONS.info_dict.get("gki_signing_key_path")
+  algorithm = OPTIONS.info_dict.get("gki_signing_algorithm")
+
+  key_path = ResolveAVBSigningPathArgs(key_path)
+
+  # Checks key_path exists, before processing --gki_signing_* args.
+  if not os.path.exists(key_path):
+    raise ExternalError(
+        'gki_signing_key_path: "{}" not found'.format(key_path))
+
+  output_certificate = tempfile.NamedTemporaryFile()
+  cmd = [
+      "generate_gki_certificate",
+      "--name", image_name,
+      "--algorithm", algorithm,
+      "--key", key_path,
+      "--output", output_certificate.name,
+      image,
+  ]
+
+  signature_args = OPTIONS.info_dict.get("gki_signing_signature_args", "")
+  signature_args = signature_args.strip()
+  if signature_args:
+    cmd.extend(["--additional_avb_args", signature_args])
+
+  args = OPTIONS.info_dict.get("avb_boot_add_hash_footer_args", "")
+  args = args.strip()
+  if args:
+    cmd.extend(["--additional_avb_args", args])
+
+  RunAndCheckOutput(cmd)
+
+  output_certificate.seek(os.SEEK_SET, 0)
+  data = output_certificate.read()
+  output_certificate.close()
+  return data
+
+
 def BuildVBMeta(image_path, partitions, name, needed_partitions,
                 resolve_rollback_index_location_conflict=False):
   """Creates a VBMeta image.
@@ -1797,6 +1841,29 @@
 
   RunAndCheckOutput(cmd)
 
+  if _HasGkiCertificationArgs():
+    if not os.path.exists(img.name):
+      raise ValueError("Cannot find GKI boot.img")
+    if kernel_path is None or not os.path.exists(kernel_path):
+      raise ValueError("Cannot find GKI kernel.img")
+
+    # Certify GKI images.
+    boot_signature_bytes = b''
+    boot_signature_bytes += _GenerateGkiCertificate(img.name, "boot")
+    boot_signature_bytes += _GenerateGkiCertificate(
+        kernel_path, "generic_kernel")
+
+    BOOT_SIGNATURE_SIZE = 16 * 1024
+    if len(boot_signature_bytes) > BOOT_SIGNATURE_SIZE:
+      raise ValueError(
+          f"GKI boot_signature size must be <= {BOOT_SIGNATURE_SIZE}")
+    boot_signature_bytes += (
+        b'\0' * (BOOT_SIGNATURE_SIZE - len(boot_signature_bytes)))
+    assert len(boot_signature_bytes) == BOOT_SIGNATURE_SIZE
+
+    with open(img.name, 'ab') as f:
+      f.write(boot_signature_bytes)
+
   # Sign the image if vboot is non-empty.
   if info_dict.get("vboot"):
     path = "/" + partition_name
@@ -1910,6 +1977,9 @@
   if info_dict.get("recovery_as_boot") == "true":
     return True  # the recovery-as-boot boot.img has a RECOVERY ramdisk.
 
+  if info_dict.get("gki_boot_image_without_ramdisk") == "true":
+    return False  # A GKI boot.img has no ramdisk since Android-13.
+
   if info_dict.get("system_root_image") == "true":
     # The ramdisk content is merged into the system.img, so there is NO
     # ramdisk in the boot.img or boot-<kernel version>.img.
diff --git a/tools/releasetools/sign_target_files_apks.py b/tools/releasetools/sign_target_files_apks.py
index 2fbb3b0..2b45825 100755
--- a/tools/releasetools/sign_target_files_apks.py
+++ b/tools/releasetools/sign_target_files_apks.py
@@ -123,6 +123,17 @@
       mounted on the partition (e.g. "--signing_helper /path/to/helper"). The
       args will be appended to the existing ones in info dict.
 
+  --gki_signing_algorithm <algorithm>
+  --gki_signing_key <key>
+      Use the specified algorithm (e.g. SHA256_RSA4096) and the key to generate
+      'boot signature' in a v4 boot.img. Otherwise it uses the existing values
+      in info dict.
+
+  --gki_signing_extra_args <args>
+      Specify any additional args that are needed to generate 'boot signature'
+      (e.g. --prop foo:bar). The args will be appended to the existing ones
+      in info dict.
+
   --android_jar_path <path>
       Path to the android.jar to repack the apex file.
 
@@ -182,6 +193,9 @@
 OPTIONS.avb_keys = {}
 OPTIONS.avb_algorithms = {}
 OPTIONS.avb_extra_args = {}
+OPTIONS.gki_signing_key = None
+OPTIONS.gki_signing_algorithm = None
+OPTIONS.gki_signing_extra_args = None
 OPTIONS.android_jar_path = None
 OPTIONS.vendor_partitions = set()
 OPTIONS.vendor_otatools = None
@@ -538,7 +552,7 @@
         [len(os.path.basename(i.filename)) for i in input_tf_zip.infolist()
          if GetApkFileInfo(i.filename, compressed_extension, [])[0]])
   except ValueError:
-    # Sets this to zero for targets without APK files.
+    # Sets this to zero for targets without APK files, e.g., gki_arm64.
     maxsize = 0
 
   system_root_image = misc_info.get("system_root_image") == "true"
@@ -754,6 +768,9 @@
   if misc_info.get('avb_enable') == 'true':
     RewriteAvbProps(misc_info)
 
+  # Replace the GKI signing key for boot.img, if any.
+  ReplaceGkiSigningKey(misc_info)
+
   # Write back misc_info with the latest values.
   ReplaceMiscInfoTxt(input_tf_zip, output_tf_zip, misc_info)
 
@@ -1035,6 +1052,27 @@
       misc_info[args_key] = result
 
 
+def ReplaceGkiSigningKey(misc_info):
+  """Replaces the GKI signing key."""
+
+  key = OPTIONS.gki_signing_key
+  if not key:
+    return
+
+  algorithm = OPTIONS.gki_signing_algorithm
+  if not algorithm:
+    raise ValueError("Missing --gki_signing_algorithm")
+
+  print('Replacing GKI signing key with "%s" (%s)' % (key, algorithm))
+  misc_info["gki_signing_algorithm"] = algorithm
+  misc_info["gki_signing_key_path"] = key
+
+  extra_args = OPTIONS.gki_signing_extra_args
+  if extra_args:
+    print('Setting GKI signing args: "%s"' % (extra_args))
+    misc_info["gki_signing_signature_args"] = extra_args
+
+
 def BuildKeyMap(misc_info, key_mapping_options):
   for s, d in key_mapping_options:
     if s is None:   # -d option
@@ -1388,6 +1426,12 @@
       # 'oem=--signing_helper_with_files=/tmp/avbsigner.sh'.
       partition, extra_args = a.split("=", 1)
       OPTIONS.avb_extra_args[partition] = extra_args
+    elif o == "--gki_signing_key":
+      OPTIONS.gki_signing_key = a
+    elif o == "--gki_signing_algorithm":
+      OPTIONS.gki_signing_algorithm = a
+    elif o == "--gki_signing_extra_args":
+      OPTIONS.gki_signing_extra_args = a
     elif o == "--vendor_otatools":
       OPTIONS.vendor_otatools = a
     elif o == "--vendor_partitions":
@@ -1451,6 +1495,9 @@
           "avb_extra_custom_image_key=",
           "avb_extra_custom_image_algorithm=",
           "avb_extra_custom_image_extra_args=",
+          "gki_signing_key=",
+          "gki_signing_algorithm=",
+          "gki_signing_extra_args=",
           "vendor_partitions=",
           "vendor_otatools=",
           "allow_gsi_debug_sepolicy",
diff --git a/tools/releasetools/test_common.py b/tools/releasetools/test_common.py
index c61c290..14f0e88 100644
--- a/tools/releasetools/test_common.py
+++ b/tools/releasetools/test_common.py
@@ -1636,6 +1636,40 @@
     self.assertEqual(3, chained_partition_args.rollback_index_location)
     self.assertTrue(os.path.exists(chained_partition_args.pubkey_path))
 
+  def test_GenerateGkiCertificate_KeyPathNotFound(self):
+    pubkey = os.path.join(self.testdata_dir, 'no_testkey_gki.pem')
+    self.assertFalse(os.path.exists(pubkey))
+
+    common.OPTIONS.info_dict = {
+        'gki_signing_key_path': pubkey,
+        'gki_signing_algorithm': 'SHA256_RSA4096',
+        'gki_signing_signature_args': '--prop foo:bar',
+    }
+    common.OPTIONS.search_path = None
+    test_file = tempfile.NamedTemporaryFile()
+    self.assertRaises(common.ExternalError, common._GenerateGkiCertificate,
+                      test_file.name, 'generic_kernel')
+
+  def test_GenerateGkiCertificate_SearchKeyPathNotFound(self):
+    pubkey = 'no_testkey_gki.pem'
+    self.assertFalse(os.path.exists(pubkey))
+
+    # Tests it should raise ExternalError if no key found under
+    # OPTIONS.search_path.
+    search_path_dir = common.MakeTempDir()
+    search_pubkey = os.path.join(search_path_dir, pubkey)
+    self.assertFalse(os.path.exists(search_pubkey))
+
+    common.OPTIONS.search_path = search_path_dir
+    common.OPTIONS.info_dict = {
+        'gki_signing_key_path': pubkey,
+        'gki_signing_algorithm': 'SHA256_RSA4096',
+        'gki_signing_signature_args': '--prop foo:bar',
+    }
+    test_file = tempfile.NamedTemporaryFile()
+    self.assertRaises(common.ExternalError, common._GenerateGkiCertificate,
+                      test_file.name, 'generic_kernel')
+
 
 class InstallRecoveryScriptFormatTest(test_utils.ReleaseToolsTestCase):
   """Checks the format of install-recovery.sh.
diff --git a/tools/releasetools/test_sign_target_files_apks.py b/tools/releasetools/test_sign_target_files_apks.py
index 9cc6df4..0cd7dac 100644
--- a/tools/releasetools/test_sign_target_files_apks.py
+++ b/tools/releasetools/test_sign_target_files_apks.py
@@ -23,7 +23,8 @@
 import test_utils
 from sign_target_files_apks import (
     CheckApkAndApexKeysAvailable, EditTags, GetApkFileInfo, ReadApexKeysInfo,
-    ReplaceCerts, RewriteAvbProps, RewriteProps, WriteOtacerts)
+    ReplaceCerts, ReplaceGkiSigningKey, RewriteAvbProps, RewriteProps,
+    WriteOtacerts)
 
 
 class SignTargetFilesApksTest(test_utils.ReleaseToolsTestCase):
@@ -535,3 +536,52 @@
             'system/apex/apexd/apexd_testdata/com.android.apex.test_package_2.pem',
             'build/make/target/product/security/testkey', None),
         }, keys_info)
+
+  def test_ReplaceGkiSigningKey(self):
+    common.OPTIONS.gki_signing_key = 'release_gki_key'
+    common.OPTIONS.gki_signing_algorithm = 'release_gki_algorithm'
+    common.OPTIONS.gki_signing_extra_args = 'release_gki_signature_extra_args'
+
+    misc_info = {
+        'gki_signing_key_path': 'default_gki_key',
+        'gki_signing_algorithm': 'default_gki_algorithm',
+        'gki_signing_signature_args': 'default_gki_signature_args',
+    }
+    expected_dict = {
+        'gki_signing_key_path': 'release_gki_key',
+        'gki_signing_algorithm': 'release_gki_algorithm',
+        'gki_signing_signature_args': 'release_gki_signature_extra_args',
+    }
+    ReplaceGkiSigningKey(misc_info)
+    self.assertDictEqual(expected_dict, misc_info)
+
+  def test_ReplaceGkiSigningKey_MissingSigningAlgorithm(self):
+    common.OPTIONS.gki_signing_key = 'release_gki_key'
+    common.OPTIONS.gki_signing_algorithm = None
+    common.OPTIONS.gki_signing_extra_args = 'release_gki_signature_extra_args'
+
+    misc_info = {
+        'gki_signing_key_path': 'default_gki_key',
+        'gki_signing_algorithm': 'default_gki_algorithm',
+        'gki_signing_signature_args': 'default_gki_signature_args',
+    }
+    self.assertRaises(ValueError, ReplaceGkiSigningKey, misc_info)
+
+  def test_ReplaceGkiSigningKey_MissingSigningKeyNop(self):
+    common.OPTIONS.gki_signing_key = None
+    common.OPTIONS.gki_signing_algorithm = 'release_gki_algorithm'
+    common.OPTIONS.gki_signing_extra_args = 'release_gki_signature_extra_args'
+
+    # No change to misc_info if common.OPTIONS.gki_signing_key is missing.
+    misc_info = {
+        'gki_signing_key_path': 'default_gki_key',
+        'gki_signing_algorithm': 'default_gki_algorithm',
+        'gki_signing_signature_args': 'default_gki_signature_args',
+    }
+    expected_dict = {
+        'gki_signing_key_path': 'default_gki_key',
+        'gki_signing_algorithm': 'default_gki_algorithm',
+        'gki_signing_signature_args': 'default_gki_signature_args',
+    }
+    ReplaceGkiSigningKey(misc_info)
+    self.assertDictEqual(expected_dict, misc_info)
diff --git a/tools/releasetools/validate_target_files.py b/tools/releasetools/validate_target_files.py
index 84a2f7e..82b3107 100755
--- a/tools/releasetools/validate_target_files.py
+++ b/tools/releasetools/validate_target_files.py
@@ -132,7 +132,7 @@
     return
 
   # Verify IMAGES/system.img if applicable.
-  # Some targets are system.img-less.
+  # Some targets, e.g., gki_arm64, gki_x86_64, etc., are system.img-less.
   if 'IMAGES/system.img' in input_zip.namelist():
     CheckAllFiles('system')