diff --git a/tools/releasetools/ota_utils.py b/tools/releasetools/ota_utils.py
index 8993da9eb751..9b3367ebe11b 100644
--- a/tools/releasetools/ota_utils.py
+++ b/tools/releasetools/ota_utils.py
@@ -897,30 +897,7 @@ def Sign(self, payload_signer):
     """
     assert isinstance(payload_signer, PayloadSigner)
 
-    # 1. Generate hashes of the payload and metadata files.
-    payload_sig_file = common.MakeTempFile(prefix="sig-", suffix=".bin")
-    metadata_sig_file = common.MakeTempFile(prefix="sig-", suffix=".bin")
-    cmd = ["brillo_update_payload", "hash",
-           "--unsigned_payload", self.payload_file,
-           "--signature_size", str(payload_signer.maximum_signature_size),
-           "--metadata_hash_file", metadata_sig_file,
-           "--payload_hash_file", payload_sig_file]
-    self._Run(cmd)
-
-    # 2. Sign the hashes.
-    signed_payload_sig_file = payload_signer.SignHashFile(payload_sig_file)
-    signed_metadata_sig_file = payload_signer.SignHashFile(metadata_sig_file)
-
-    # 3. Insert the signatures back into the payload file.
-    signed_payload_file = common.MakeTempFile(prefix="signed-payload-",
-                                              suffix=".bin")
-    cmd = ["brillo_update_payload", "sign",
-           "--unsigned_payload", self.payload_file,
-           "--payload", signed_payload_file,
-           "--signature_size", str(payload_signer.maximum_signature_size),
-           "--metadata_signature_file", signed_metadata_sig_file,
-           "--payload_signature_file", signed_payload_sig_file]
-    self._Run(cmd)
+    signed_payload_file = payload_signer.SignPayload(self.payload_file)
 
     self.payload_file = signed_payload_file
 
diff --git a/tools/releasetools/payload_signer.py b/tools/releasetools/payload_signer.py
index 9933aefeb859..bbd2896508fb 100644
--- a/tools/releasetools/payload_signer.py
+++ b/tools/releasetools/payload_signer.py
@@ -95,11 +95,11 @@ def SignPayload(self, unsigned_payload):
     # 1. Generate hashes of the payload and metadata files.
     payload_sig_file = common.MakeTempFile(prefix="sig-", suffix=".bin")
     metadata_sig_file = common.MakeTempFile(prefix="sig-", suffix=".bin")
-    cmd = ["brillo_update_payload", "hash",
-           "--unsigned_payload", unsigned_payload,
-           "--signature_size", str(self.maximum_signature_size),
-           "--metadata_hash_file", metadata_sig_file,
-           "--payload_hash_file", payload_sig_file]
+    cmd = ["delta_generator",
+           "--in_file=" + unsigned_payload,
+           "--signature_size=" + str(self.maximum_signature_size),
+           "--out_metadata_hash_file=" + metadata_sig_file,
+           "--out_hash_file=" + payload_sig_file]
     self._Run(cmd)
 
     # 2. Sign the hashes.
@@ -109,16 +109,15 @@ def SignPayload(self, unsigned_payload):
     # 3. Insert the signatures back into the payload file.
     signed_payload_file = common.MakeTempFile(prefix="signed-payload-",
                                               suffix=".bin")
-    cmd = ["brillo_update_payload", "sign",
-           "--unsigned_payload", unsigned_payload,
-           "--payload", signed_payload_file,
-           "--signature_size", str(self.maximum_signature_size),
-           "--metadata_signature_file", signed_metadata_sig_file,
-           "--payload_signature_file", signed_payload_sig_file]
+    cmd = ["delta_generator",
+           "--in_file=" + unsigned_payload,
+           "--out_file=" + signed_payload_file,
+           "--signature_size=" + str(self.maximum_signature_size),
+           "--metadata_signature_file=" + signed_metadata_sig_file,
+           "--payload_signature_file=" + signed_payload_sig_file]
     self._Run(cmd)
     return signed_payload_file
 
-
   def SignHashFile(self, in_file):
     """Signs the given input file. Returns the output filename."""
     out_file = common.MakeTempFile(prefix="signed-", suffix=".bin")