diff --git a/core/Makefile b/core/Makefile
index 2e72727..0b55c55 100644
--- a/core/Makefile
+++ b/core/Makefile
@@ -4323,6 +4323,7 @@
   shflags \
   sign_apex \
   sign_target_files_apks \
+  sign_virt_apex \
   signapk \
   simg2img \
   sload_f2fs \
diff --git a/tools/releasetools/apex_utils.py b/tools/releasetools/apex_utils.py
index 211af0a..ee0feae 100644
--- a/tools/releasetools/apex_utils.py
+++ b/tools/releasetools/apex_utils.py
@@ -142,6 +142,7 @@
       has_signed_content = True
 
     if self.sign_tool:
+      logger.info('Signing payload contents in apex %s with %s', self.apex_path, self.sign_tool)
       cmd = [self.sign_tool, '--avbtool', self.avbtool, payload_key, payload_dir]
       common.RunAndCheckOutput(cmd)
       has_signed_content = True
diff --git a/tools/releasetools/common.py b/tools/releasetools/common.py
index 5affa32..2ee4b8e 100644
--- a/tools/releasetools/common.py
+++ b/tools/releasetools/common.py
@@ -2107,7 +2107,7 @@
   devnull = open("/dev/null", "w+b")
   for k in sorted(keylist):
     # We don't need a password for things that aren't really keys.
-    if k in SPECIAL_CERT_STRINGS:
+    if k in SPECIAL_CERT_STRINGS or k is None:
       no_passwords.append(k)
       continue
 
diff --git a/tools/releasetools/sign_target_files_apks.py b/tools/releasetools/sign_target_files_apks.py
index bd5d7d3..5626980 100755
--- a/tools/releasetools/sign_target_files_apks.py
+++ b/tools/releasetools/sign_target_files_apks.py
@@ -262,7 +262,7 @@
 
   Args:
     keys_info: A dict that maps from APEX filenames to a tuple of (payload_key,
-        container_key).
+        container_key, sign_tool).
     key_map: A dict that overrides the keys, specified via command-line input.
 
   Returns:
@@ -280,11 +280,11 @@
     if apex not in keys_info:
       logger.warning('Failed to find %s in target_files; Ignored', apex)
       continue
-    keys_info[apex] = (key, keys_info[apex][1])
+    keys_info[apex] = (key, keys_info[apex][1], keys_info[apex][2])
 
   # Apply the key remapping to container keys.
-  for apex, (payload_key, container_key) in keys_info.items():
-    keys_info[apex] = (payload_key, key_map.get(container_key, container_key))
+  for apex, (payload_key, container_key, sign_tool) in keys_info.items():
+    keys_info[apex] = (payload_key, key_map.get(container_key, container_key), sign_tool)
 
   # Apply all the --extra_apks options to override the container keys.
   for apex, key in OPTIONS.extra_apks.items():
@@ -293,13 +293,13 @@
       continue
     if not key:
       key = 'PRESIGNED'
-    keys_info[apex] = (keys_info[apex][0], key_map.get(key, key))
+    keys_info[apex] = (keys_info[apex][0], key_map.get(key, key), keys_info[apex][2])
 
   # A PRESIGNED container entails a PRESIGNED payload. Apply this to all the
   # APEX key pairs. However, a PRESIGNED container with non-PRESIGNED payload
   # (overridden via commandline) indicates a config error, which should not be
   # allowed.
-  for apex, (payload_key, container_key) in keys_info.items():
+  for apex, (payload_key, container_key, sign_tool) in keys_info.items():
     if container_key != 'PRESIGNED':
       continue
     if apex in OPTIONS.extra_apex_payload_keys:
@@ -311,7 +311,7 @@
       print(
           "Setting {} payload as PRESIGNED due to PRESIGNED container".format(
               apex))
-    keys_info[apex] = ('PRESIGNED', 'PRESIGNED')
+    keys_info[apex] = ('PRESIGNED', 'PRESIGNED', None)
 
   return keys_info
 
@@ -372,7 +372,7 @@
     compressed_extension: The extension string of compressed APKs, such as
         '.gz', or None if there's no compressed APKs.
     apex_keys: A dict that contains the key mapping from APEX name to
-        (payload_key, container_key).
+        (payload_key, container_key, sign_tool).
 
   Raises:
     AssertionError: On finding unknown APKs and APEXes.
@@ -417,7 +417,7 @@
 
     name = GetApexFilename(info.filename)
 
-    (payload_key, container_key) = apex_keys[name]
+    (payload_key, container_key, _) = apex_keys[name]
     if ((payload_key in common.SPECIAL_CERT_STRINGS and
          container_key not in common.SPECIAL_CERT_STRINGS) or
         (payload_key not in common.SPECIAL_CERT_STRINGS and
@@ -569,7 +569,7 @@
     elif IsApexFile(filename):
       name = GetApexFilename(filename)
 
-      payload_key, container_key = apex_keys[name]
+      payload_key, container_key, sign_tool = apex_keys[name]
 
       # We've asserted not having a case with only one of them PRESIGNED.
       if (payload_key not in common.SPECIAL_CERT_STRINGS and
@@ -588,7 +588,8 @@
             apk_keys,
             codename_to_api_level_map,
             no_hashtree=None,  # Let apex_util determine if hash tree is needed
-            signing_args=OPTIONS.avb_extra_args.get('apex'))
+            signing_args=OPTIONS.avb_extra_args.get('apex'),
+            sign_tool=sign_tool)
         common.ZipWrite(output_tf_zip, signed_apex, filename)
 
       else:
@@ -1147,15 +1148,16 @@
 
   Given a target-files ZipFile, parses the META/apexkeys.txt entry and returns a
   dict that contains the mapping from APEX names (e.g. com.android.tzdata) to a
-  tuple of (payload_key, container_key).
+  tuple of (payload_key, container_key, sign_tool).
 
   Args:
     tf_zip: The input target_files ZipFile (already open).
 
   Returns:
-    (payload_key, container_key): payload_key contains the path to the payload
-        signing key; container_key contains the path to the container signing
-        key.
+    (payload_key, container_key, sign_tool):
+      - payload_key contains the path to the payload signing key
+      - container_key contains the path to the container signing key
+      - sign_tool is an apex-specific signing tool for its payload contents
   """
   keys = {}
   for line in tf_zip.read('META/apexkeys.txt').decode().split('\n'):
@@ -1168,7 +1170,8 @@
         r'private_key="(?P<PAYLOAD_PRIVATE_KEY>.*)"\s+'
         r'container_certificate="(?P<CONTAINER_CERT>.*)"\s+'
         r'container_private_key="(?P<CONTAINER_PRIVATE_KEY>.*?)"'
-        r'(\s+partition="(?P<PARTITION>.*?)")?$',
+        r'(\s+partition="(?P<PARTITION>.*?)")?'
+        r'(\s+sign_tool="(?P<SIGN_TOOL>.*?)")?$',
         line)
     if not matches:
       continue
@@ -1197,7 +1200,8 @@
     else:
       raise ValueError("Failed to parse container keys: \n{}".format(line))
 
-    keys[name] = (payload_private_key, container_key)
+    sign_tool = matches.group("SIGN_TOOL")
+    keys[name] = (payload_private_key, container_key, sign_tool)
 
   return keys
 
diff --git a/tools/releasetools/test_sign_target_files_apks.py b/tools/releasetools/test_sign_target_files_apks.py
index ad9e657..92dca9a 100644
--- a/tools/releasetools/test_sign_target_files_apks.py
+++ b/tools/releasetools/test_sign_target_files_apks.py
@@ -328,23 +328,23 @@
         'Apex3.apex' : 'key3',
     }
     apex_keys = {
-        'Apex1.apex' : ('payload-key1', 'container-key1'),
-        'Apex2.apex' : ('payload-key2', 'container-key2'),
+        'Apex1.apex' : ('payload-key1', 'container-key1', None),
+        'Apex2.apex' : ('payload-key2', 'container-key2', None),
     }
     with zipfile.ZipFile(input_file) as input_zip:
       CheckApkAndApexKeysAvailable(input_zip, apk_key_map, None, apex_keys)
 
       # Fine to have both keys as PRESIGNED.
-      apex_keys['Apex2.apex'] = ('PRESIGNED', 'PRESIGNED')
+      apex_keys['Apex2.apex'] = ('PRESIGNED', 'PRESIGNED', None)
       CheckApkAndApexKeysAvailable(input_zip, apk_key_map, None, apex_keys)
 
       # Having only one of them as PRESIGNED is not allowed.
-      apex_keys['Apex2.apex'] = ('payload-key2', 'PRESIGNED')
+      apex_keys['Apex2.apex'] = ('payload-key2', 'PRESIGNED', None)
       self.assertRaises(
           AssertionError, CheckApkAndApexKeysAvailable, input_zip, apk_key_map,
           None, apex_keys)
 
-      apex_keys['Apex2.apex'] = ('PRESIGNED', 'container-key1')
+      apex_keys['Apex2.apex'] = ('PRESIGNED', 'container-key1', None)
       self.assertRaises(
           AssertionError, CheckApkAndApexKeysAvailable, input_zip, apk_key_map,
           None, apex_keys)
@@ -475,10 +475,10 @@
     self.assertEqual({
         'apex.apexd_test.apex': (
             'system/apex/apexd/apexd_testdata/com.android.apex.test_package.pem',
-            'build/make/target/product/security/testkey'),
+            'build/make/target/product/security/testkey', None),
         'apex.apexd_test_different_app.apex': (
             'system/apex/apexd/apexd_testdata/com.android.apex.test_package_2.pem',
-            'build/make/target/product/security/testkey'),
+            'build/make/target/product/security/testkey', None),
         }, keys_info)
 
   def test_ReadApexKeysInfo_mismatchingContainerKeys(self):
@@ -514,10 +514,10 @@
     self.assertEqual({
         'apex.apexd_test.apex': (
             'system/apex/apexd/apexd_testdata/com.android.apex.test_package.pem',
-            'build/make/target/product/security/testkey'),
+            'build/make/target/product/security/testkey', None),
         'apex.apexd_test_different_app.apex': (
             'system/apex/apexd/apexd_testdata/com.android.apex.test_package_2.pem',
-            'build/make/target/product/security/testkey'),
+            'build/make/target/product/security/testkey', None),
         }, keys_info)
 
   def test_ReadApexKeysInfo_missingPayloadPublicKey(self):
@@ -537,10 +537,10 @@
     self.assertEqual({
         'apex.apexd_test.apex': (
             'system/apex/apexd/apexd_testdata/com.android.apex.test_package.pem',
-            'build/make/target/product/security/testkey'),
+            'build/make/target/product/security/testkey', None),
         'apex.apexd_test_different_app.apex': (
             'system/apex/apexd/apexd_testdata/com.android.apex.test_package_2.pem',
-            'build/make/target/product/security/testkey'),
+            'build/make/target/product/security/testkey', None),
         }, keys_info)
 
   def test_ReadApexKeysInfo_presignedKeys(self):
@@ -560,10 +560,10 @@
     self.assertEqual({
         'apex.apexd_test.apex': (
             'system/apex/apexd/apexd_testdata/com.android.apex.test_package.pem',
-            'build/make/target/product/security/testkey'),
+            'build/make/target/product/security/testkey', None),
         'apex.apexd_test_different_app.apex': (
             'system/apex/apexd/apexd_testdata/com.android.apex.test_package_2.pem',
-            'build/make/target/product/security/testkey'),
+            'build/make/target/product/security/testkey', None),
         }, keys_info)
 
   def test_ReadApexKeysInfo_presignedKeys(self):
@@ -583,10 +583,10 @@
     self.assertEqual({
         'apex.apexd_test.apex': (
             'system/apex/apexd/apexd_testdata/com.android.apex.test_package.pem',
-            'build/make/target/product/security/testkey'),
+            'build/make/target/product/security/testkey', None),
         'apex.apexd_test_different_app.apex': (
             'system/apex/apexd/apexd_testdata/com.android.apex.test_package_2.pem',
-            'build/make/target/product/security/testkey'),
+            'build/make/target/product/security/testkey', None),
         }, keys_info)
 
   def test_ReplaceGkiSigningKey(self):