diff --git a/tools/Android.bp b/tools/Android.bp
index e325f6b..bea0602 100644
--- a/tools/Android.bp
+++ b/tools/Android.bp
@@ -71,22 +71,6 @@
 }
 
 python_binary_host {
-    name: "generate-sbom",
-    srcs: [
-        "generate-sbom.py",
-    ],
-    version: {
-        py3: {
-            embedded_launcher: true,
-        },
-    },
-    libs: [
-        "metadata_file_proto_py",
-        "libprotobuf-python",
-    ],
-}
-
-python_binary_host {
     name: "list_files",
     main: "list_files.py",
     srcs: [
diff --git a/tools/generate-sbom.py b/tools/generate-sbom.py
deleted file mode 100755
index 9583395..0000000
--- a/tools/generate-sbom.py
+++ /dev/null
@@ -1,690 +0,0 @@
-#!/usr/bin/env python3
-#
-# Copyright (C) 2023 The Android Open Source Project
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#      http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-
-"""
-Generate the SBOM of the current target product in SPDX format.
-Usage example:
-  generate-sbom.py --output_file out/target/product/vsoc_x86_64/sbom.spdx \
-                   --metadata out/target/product/vsoc_x86_64/sbom-metadata.csv \
-                   --product_out_dir=out/target/product/vsoc_x86_64 \
-                   --build_version $(cat out/target/product/vsoc_x86_64/build_fingerprint.txt) \
-                   --product_mfr=Google
-"""
-
-import argparse
-import csv
-import datetime
-import google.protobuf.text_format as text_format
-import hashlib
-import json
-import os
-import metadata_file_pb2
-
-# Common
-SPDXID = 'SPDXID'
-SPDX_VERSION = 'SPDXVersion'
-DATA_LICENSE = 'DataLicense'
-DOCUMENT_NAME = 'DocumentName'
-DOCUMENT_NAMESPACE = 'DocumentNamespace'
-CREATED = 'Created'
-CREATOR = 'Creator'
-EXTERNAL_DOCUMENT_REF = 'ExternalDocumentRef'
-
-# Package
-PACKAGE_NAME = 'PackageName'
-PACKAGE_DOWNLOAD_LOCATION = 'PackageDownloadLocation'
-PACKAGE_VERSION = 'PackageVersion'
-PACKAGE_SUPPLIER = 'PackageSupplier'
-FILES_ANALYZED = 'FilesAnalyzed'
-PACKAGE_VERIFICATION_CODE = 'PackageVerificationCode'
-PACKAGE_EXTERNAL_REF = 'ExternalRef'
-# Package license
-PACKAGE_LICENSE_CONCLUDED = 'PackageLicenseConcluded'
-PACKAGE_LICENSE_INFO_FROM_FILES = 'PackageLicenseInfoFromFiles'
-PACKAGE_LICENSE_DECLARED = 'PackageLicenseDeclared'
-PACKAGE_LICENSE_COMMENTS = 'PackageLicenseComments'
-
-# File
-FILE_NAME = 'FileName'
-FILE_CHECKSUM = 'FileChecksum'
-# File license
-FILE_LICENSE_CONCLUDED = 'LicenseConcluded'
-FILE_LICENSE_INFO_IN_FILE = 'LicenseInfoInFile'
-FILE_LICENSE_COMMENTS = 'LicenseComments'
-FILE_COPYRIGHT_TEXT = 'FileCopyrightText'
-FILE_NOTICE = 'FileNotice'
-FILE_ATTRIBUTION_TEXT = 'FileAttributionText'
-
-# Relationship
-RELATIONSHIP = 'Relationship'
-REL_DESCRIBES = 'DESCRIBES'
-REL_VARIANT_OF = 'VARIANT_OF'
-REL_GENERATED_FROM = 'GENERATED_FROM'
-
-# Package type
-PKG_SOURCE = 'SOURCE'
-PKG_UPSTREAM = 'UPSTREAM'
-PKG_PREBUILT = 'PREBUILT'
-
-# Security tag
-NVD_CPE23 = 'NVD-CPE2.3:'
-
-# Report
-ISSUE_NO_METADATA = 'No metadata generated in Make for installed files:'
-ISSUE_NO_METADATA_FILE = 'No METADATA file found for installed file:'
-ISSUE_METADATA_FILE_INCOMPLETE = 'METADATA file incomplete:'
-ISSUE_UNKNOWN_SECURITY_TAG_TYPE = 'Unknown security tag type:'
-ISSUE_INSTALLED_FILE_NOT_EXIST = 'Non-exist installed files:'
-INFO_METADATA_FOUND_FOR_PACKAGE = 'METADATA file found for packages:'
-
-
-def get_args():
-  parser = argparse.ArgumentParser()
-  parser.add_argument('-v', '--verbose', action='store_true', default=False, help='Print more information.')
-  parser.add_argument('--output_file', required=True, help='The generated SBOM file in SPDX format.')
-  parser.add_argument('--metadata', required=True, help='The SBOM metadata file path.')
-  parser.add_argument('--product_out_dir', required=True, help='The parent directory of all the installed files.')
-  parser.add_argument('--build_version', required=True, help='The build version.')
-  parser.add_argument('--product_mfr', required=True, help='The product manufacturer.')
-  parser.add_argument('--json', action='store_true', default=False, help='Generated SBOM file in SPDX JSON format')
-  parser.add_argument('--unbundled', action='store_true', default=False, help='Generate SBOM file for unbundled module')
-
-  return parser.parse_args()
-
-
-def log(*info):
-  if args.verbose:
-    for i in info:
-      print(i)
-
-
-def new_doc_header(doc_id):
-  return {
-      SPDX_VERSION: 'SPDX-2.3',
-      DATA_LICENSE: 'CC0-1.0',
-      SPDXID: doc_id,
-      DOCUMENT_NAME: args.build_version,
-      DOCUMENT_NAMESPACE: f'https://www.google.com/sbom/spdx/android/{args.build_version}',
-      CREATOR: 'Organization: Google, LLC',
-      CREATED: '<timestamp>',
-      EXTERNAL_DOCUMENT_REF: [],
-  }
-
-
-def new_package_record(id, name, version, supplier, download_location=None, files_analyzed='false', external_refs=[]):
-  package = {
-      PACKAGE_NAME: name,
-      SPDXID: id,
-      PACKAGE_DOWNLOAD_LOCATION: download_location if download_location else 'NONE',
-      FILES_ANALYZED: files_analyzed,
-  }
-  if version:
-    package[PACKAGE_VERSION] = version
-  if supplier:
-    package[PACKAGE_SUPPLIER] = f'Organization: {supplier}'
-  if external_refs:
-    package[PACKAGE_EXTERNAL_REF] = external_refs
-
-  return package
-
-
-def new_file_record(id, name, checksum):
-  return {
-      FILE_NAME: name,
-      SPDXID: id,
-      FILE_CHECKSUM: checksum
-  }
-
-
-def encode_for_spdxid(s):
-  """Simple encode for string values used in SPDXID which uses the charset of A-Za-Z0-9.-"""
-  result = ''
-  for c in s:
-    if c.isalnum() or c in '.-':
-      result += c
-    elif c in '_@/':
-      result += '-'
-    else:
-      result += '0x' + c.encode('utf-8').hex()
-
-  return result.lstrip('-')
-
-
-def new_package_id(package_name, type):
-  return f'SPDXRef-{type}-{encode_for_spdxid(package_name)}'
-
-
-def new_external_doc_ref(package_name, sbom_url, sbom_checksum):
-  doc_ref_id = f'DocumentRef-{PKG_UPSTREAM}-{encode_for_spdxid(package_name)}'
-  return f'{EXTERNAL_DOCUMENT_REF}: {doc_ref_id} {sbom_url} {sbom_checksum}', doc_ref_id
-
-
-def new_file_id(file_path):
-  return f'SPDXRef-{encode_for_spdxid(file_path)}'
-
-
-def new_relationship_record(id1, relationship, id2):
-  return f'{RELATIONSHIP}: {id1} {relationship} {id2}'
-
-
-def checksum(file_path):
-  file_path = args.product_out_dir + '/' + file_path
-  h = hashlib.sha1()
-  if os.path.islink(file_path):
-    h.update(os.readlink(file_path).encode('utf-8'))
-  else:
-    with open(file_path, 'rb') as f:
-      h.update(f.read())
-  return f'SHA1: {h.hexdigest()}'
-
-
-def is_soong_prebuilt_module(file_metadata):
-  return file_metadata['soong_module_type'] and file_metadata['soong_module_type'] in [
-      'android_app_import', 'android_library_import', 'cc_prebuilt_binary', 'cc_prebuilt_library',
-      'cc_prebuilt_library_headers', 'cc_prebuilt_library_shared', 'cc_prebuilt_library_static', 'cc_prebuilt_object',
-      'dex_import', 'java_import', 'java_sdk_library_import', 'java_system_modules_import',
-      'libclang_rt_prebuilt_library_static', 'libclang_rt_prebuilt_library_shared', 'llvm_prebuilt_library_static',
-      'ndk_prebuilt_object', 'ndk_prebuilt_shared_stl', 'nkd_prebuilt_static_stl', 'prebuilt_apex',
-      'prebuilt_bootclasspath_fragment', 'prebuilt_dsp', 'prebuilt_firmware', 'prebuilt_kernel_modules',
-      'prebuilt_rfsa', 'prebuilt_root', 'rust_prebuilt_dylib', 'rust_prebuilt_library', 'rust_prebuilt_rlib',
-      'vndk_prebuilt_shared',
-
-      # 'android_test_import',
-      # 'cc_prebuilt_test_library_shared',
-      # 'java_import_host',
-      # 'java_test_import',
-      # 'llvm_host_prebuilt_library_shared',
-      # 'prebuilt_apis',
-      # 'prebuilt_build_tool',
-      # 'prebuilt_defaults',
-      # 'prebuilt_etc',
-      # 'prebuilt_etc_host',
-      # 'prebuilt_etc_xml',
-      # 'prebuilt_font',
-      # 'prebuilt_hidl_interfaces',
-      # 'prebuilt_platform_compat_config',
-      # 'prebuilt_stubs_sources',
-      # 'prebuilt_usr_share',
-      # 'prebuilt_usr_share_host',
-      # 'soong_config_module_type_import',
-  ]
-
-
-def is_source_package(file_metadata):
-  module_path = file_metadata['module_path']
-  return module_path.startswith('external/') and not is_prebuilt_package(file_metadata)
-
-
-def is_prebuilt_package(file_metadata):
-  module_path = file_metadata['module_path']
-  if module_path:
-    return (module_path.startswith('prebuilts/') or
-            is_soong_prebuilt_module(file_metadata) or
-            file_metadata['is_prebuilt_make_module'])
-
-  kernel_module_copy_files = file_metadata['kernel_module_copy_files']
-  if kernel_module_copy_files and not kernel_module_copy_files.startswith('ANDROID-GEN:'):
-    return True
-
-  return False
-
-
-def get_source_package_info(file_metadata, metadata_file_path):
-  if not metadata_file_path:
-    return file_metadata['module_path'], []
-
-  metadata_proto = metadata_file_protos[metadata_file_path]
-  external_refs = []
-  for tag in metadata_proto.third_party.security.tag:
-    if tag.lower().startswith((NVD_CPE23 + 'cpe:2.3:').lower()):
-      external_refs.append(f'{PACKAGE_EXTERNAL_REF}: SECURITY cpe23Type {tag.removeprefix(NVD_CPE23)}')
-    elif tag.lower().startswith((NVD_CPE23 + 'cpe:/').lower()):
-      external_refs.append(f'{PACKAGE_EXTERNAL_REF}: SECURITY cpe22Type {tag.removeprefix(NVD_CPE23)}')
-
-  if metadata_proto.name:
-    return metadata_proto.name, external_refs
-  else:
-    return os.path.basename(metadata_file_path), external_refs  # return the directory name only as package name
-
-
-def get_prebuilt_package_name(file_metadata, metadata_file_path):
-  name = None
-  if metadata_file_path:
-    metadata_proto = metadata_file_protos[metadata_file_path]
-    if metadata_proto.name:
-      name = metadata_proto.name
-    else:
-      name = metadata_file_path
-  elif file_metadata['module_path']:
-    name = file_metadata['module_path']
-  elif file_metadata['kernel_module_copy_files']:
-    src_path = file_metadata['kernel_module_copy_files'].split(':')[0]
-    name = os.path.dirname(src_path)
-
-  return name.removeprefix('prebuilts/').replace('/', '-')
-
-
-def get_metadata_file_path(file_metadata):
-  metadata_path = ''
-  if file_metadata['module_path']:
-    metadata_path = file_metadata['module_path']
-  elif file_metadata['kernel_module_copy_files']:
-    metadata_path = os.path.dirname(file_metadata['kernel_module_copy_files'].split(':')[0])
-
-  while metadata_path and not os.path.exists(metadata_path + '/METADATA'):
-    metadata_path = os.path.dirname(metadata_path)
-
-  return metadata_path
-
-
-def get_package_version(metadata_file_path):
-  if not metadata_file_path:
-    return None
-  metadata_proto = metadata_file_protos[metadata_file_path]
-  return metadata_proto.third_party.version
-
-
-def get_package_homepage(metadata_file_path):
-  if not metadata_file_path:
-    return None
-  metadata_proto = metadata_file_protos[metadata_file_path]
-  if metadata_proto.third_party.homepage:
-    return metadata_proto.third_party.homepage
-  for url in metadata_proto.third_party.url:
-    if url.type == metadata_file_pb2.URL.Type.HOMEPAGE:
-      return url.value
-
-  return None
-
-
-def get_package_download_location(metadata_file_path):
-  if not metadata_file_path:
-    return None
-  metadata_proto = metadata_file_protos[metadata_file_path]
-  if metadata_proto.third_party.url:
-    urls = sorted(metadata_proto.third_party.url, key=lambda url: url.type)
-    if urls[0].type != metadata_file_pb2.URL.Type.HOMEPAGE:
-      return urls[0].value
-    elif len(urls) > 1:
-      return urls[1].value
-
-  return None
-
-
-def get_sbom_fragments(installed_file_metadata, metadata_file_path):
-  external_doc_ref = None
-  packages = []
-  relationships = []
-
-  # Info from METADATA file
-  homepage = get_package_homepage(metadata_file_path)
-  version = get_package_version(metadata_file_path)
-  download_location = get_package_download_location(metadata_file_path)
-
-  if is_source_package(installed_file_metadata):
-    # Source fork packages
-    name, external_refs = get_source_package_info(installed_file_metadata, metadata_file_path)
-    source_package_id = new_package_id(name, PKG_SOURCE)
-    source_package = new_package_record(source_package_id, name, args.build_version, args.product_mfr,
-                                        external_refs=external_refs)
-
-    upstream_package_id = new_package_id(name, PKG_UPSTREAM)
-    upstream_package = new_package_record(upstream_package_id, name, version, homepage, download_location)
-    packages += [source_package, upstream_package]
-    relationships.append(new_relationship_record(source_package_id, REL_VARIANT_OF, upstream_package_id))
-  elif is_prebuilt_package(installed_file_metadata):
-    # Prebuilt fork packages
-    name = get_prebuilt_package_name(installed_file_metadata, metadata_file_path)
-    prebuilt_package_id = new_package_id(name, PKG_PREBUILT)
-    prebuilt_package = new_package_record(prebuilt_package_id, name, args.build_version, args.product_mfr)
-    packages.append(prebuilt_package)
-
-    if metadata_file_path:
-      metadata_proto = metadata_file_protos[metadata_file_path]
-      if metadata_proto.third_party.WhichOneof('sbom') == 'sbom_ref':
-        sbom_url = metadata_proto.third_party.sbom_ref.url
-        sbom_checksum = metadata_proto.third_party.sbom_ref.checksum
-        upstream_element_id = metadata_proto.third_party.sbom_ref.element_id
-        if sbom_url and sbom_checksum and upstream_element_id:
-          external_doc_ref, doc_ref_id = new_external_doc_ref(name, sbom_url, sbom_checksum)
-          relationships.append(
-              new_relationship_record(prebuilt_package_id, REL_VARIANT_OF, doc_ref_id + ':' + upstream_element_id))
-
-  return external_doc_ref, packages, relationships
-
-
-def generate_package_verification_code(files):
-  checksums = [file[FILE_CHECKSUM] for file in files]
-  checksums.sort()
-  h = hashlib.sha1()
-  h.update(''.join(checksums).encode(encoding='utf-8'))
-  return h.hexdigest()
-
-
-def write_record(f, record):
-  if record.__class__.__name__ == 'dict':
-    for k, v in record.items():
-      if k == EXTERNAL_DOCUMENT_REF or k == PACKAGE_EXTERNAL_REF:
-        for ref in v:
-          f.write(ref + '\n')
-      else:
-        f.write('{}: {}\n'.format(k, v))
-  elif record.__class__.__name__ == 'str':
-    f.write(record + '\n')
-  f.write('\n')
-
-
-def write_tagvalue_sbom(all_records):
-  with open(args.output_file, 'w', encoding="utf-8") as output_file:
-    for rec in all_records:
-      write_record(output_file, rec)
-
-
-def write_json_sbom(all_records, product_package_id):
-  doc = {}
-  product_package = None
-  for r in all_records:
-    if r.__class__.__name__ == 'dict':
-      if DOCUMENT_NAME in r:  # Doc header
-        doc['spdxVersion'] = r[SPDX_VERSION]
-        doc['dataLicense'] = r[DATA_LICENSE]
-        doc[SPDXID] = r[SPDXID]
-        doc['name'] = r[DOCUMENT_NAME]
-        doc['documentNamespace'] = r[DOCUMENT_NAMESPACE]
-        doc['creationInfo'] = {
-            'creators': [r[CREATOR]],
-            'created': r[CREATED],
-        }
-        doc['externalDocumentRefs'] = []
-        for ref in r[EXTERNAL_DOCUMENT_REF]:
-          # ref is 'ExternalDocumentRef: <doc id> <doc url> SHA1: xxxxx'
-          fields = ref.split(' ')
-          doc_ref = {
-              'externalDocumentId': fields[1],
-              'spdxDocument': fields[2],
-              'checksum': {
-                  'algorithm': fields[3][:-1],
-                  'checksumValue': fields[4]
-              }
-          }
-          doc['externalDocumentRefs'].append(doc_ref)
-        doc['documentDescribes'] = []
-        doc['packages'] = []
-        doc['files'] = []
-        doc['relationships'] = []
-
-      elif PACKAGE_NAME in r:  # packages
-        package = {
-            'name': r[PACKAGE_NAME],
-            SPDXID: r[SPDXID],
-            'downloadLocation': r[PACKAGE_DOWNLOAD_LOCATION],
-            'filesAnalyzed': r[FILES_ANALYZED] == "true"
-        }
-        if PACKAGE_VERSION in r:
-          package['versionInfo'] = r[PACKAGE_VERSION]
-        if PACKAGE_SUPPLIER in r:
-          package['supplier'] = r[PACKAGE_SUPPLIER]
-        if PACKAGE_VERIFICATION_CODE in r:
-          package['packageVerificationCode'] = {
-              'packageVerificationCodeValue': r[PACKAGE_VERIFICATION_CODE]
-          }
-        if PACKAGE_EXTERNAL_REF in r:
-          package['externalRefs'] = []
-          for ref in r[PACKAGE_EXTERNAL_REF]:
-            # ref is 'ExternalRef: SECURITY cpe22Type cpe:/a:jsoncpp_project:jsoncpp:1.9.4'
-            fields = ref.split(' ')
-            ext_ref = {
-                'referenceCategory': fields[1],
-                'referenceType': fields[2],
-                'referenceLocator': fields[3],
-            }
-            package['externalRefs'].append(ext_ref)
-
-        doc['packages'].append(package)
-        if r[SPDXID] == product_package_id:
-          product_package = package
-          product_package['hasFiles'] = []
-
-      elif FILE_NAME in r:  # files
-        file = {
-            'fileName': r[FILE_NAME],
-            SPDXID: r[SPDXID]
-        }
-        checksum = r[FILE_CHECKSUM].split(': ')
-        file['checksums'] = [{
-            'algorithm': checksum[0],
-            'checksumValue': checksum[1],
-        }]
-        doc['files'].append(file)
-        product_package['hasFiles'].append(r[SPDXID])
-
-    elif r.__class__.__name__ == 'str':
-      if r.startswith(RELATIONSHIP):
-        # r is 'Relationship: <spdxid> <relationship> <spdxid>'
-        fields = r.split(' ')
-        rel = {
-            'spdxElementId': fields[1],
-            'relatedSpdxElement': fields[3],
-            'relationshipType': fields[2],
-        }
-        if fields[2] == REL_DESCRIBES:
-          doc['documentDescribes'].append(fields[3])
-        else:
-          doc['relationships'].append(rel)
-
-  with open(args.output_file + '.json', 'w', encoding="utf-8") as output_file:
-    output_file.write(json.dumps(doc, indent=4))
-
-
-def save_report(report):
-  prefix, _ = os.path.splitext(args.output_file)
-  with open(prefix + '-gen-report.txt', 'w', encoding='utf-8') as report_file:
-    for type, issues in report.items():
-      report_file.write(type + '\n')
-      for issue in issues:
-        report_file.write('\t' + issue + '\n')
-      report_file.write('\n')
-
-
-def sort_rels(rel):
-  # rel = 'Relationship file_id GENERATED_FROM package_id'
-  fields = rel.split(' ')
-  return fields[3] + fields[1]
-
-
-# Validate the metadata generated by Make for installed files and report if there is no metadata.
-def installed_file_has_metadata(installed_file_metadata, report):
-  installed_file = installed_file_metadata['installed_file']
-  module_path = installed_file_metadata['module_path']
-  product_copy_files = installed_file_metadata['product_copy_files']
-  kernel_module_copy_files = installed_file_metadata['kernel_module_copy_files']
-  is_platform_generated = installed_file_metadata['is_platform_generated']
-
-  if (not module_path and
-      not product_copy_files and
-      not kernel_module_copy_files and
-      not is_platform_generated and
-      not installed_file.endswith('.fsv_meta')):
-    report[ISSUE_NO_METADATA].append(installed_file)
-    return False
-
-  return True
-
-
-def report_metadata_file(metadata_file_path, installed_file_metadata, report):
-  if metadata_file_path:
-    report[INFO_METADATA_FOUND_FOR_PACKAGE].append(
-        'installed_file: {}, module_path: {}, METADATA file: {}'.format(
-            installed_file_metadata['installed_file'],
-            installed_file_metadata['module_path'],
-            metadata_file_path + '/METADATA'))
-
-    package_metadata = metadata_file_pb2.Metadata()
-    with open(metadata_file_path + '/METADATA', 'rt') as f:
-      text_format.Parse(f.read(), package_metadata)
-
-    if not metadata_file_path in metadata_file_protos:
-      metadata_file_protos[metadata_file_path] = package_metadata
-      if not package_metadata.name:
-        report[ISSUE_METADATA_FILE_INCOMPLETE].append(f'{metadata_file_path}/METADATA does not has "name"')
-
-      if not package_metadata.third_party.version:
-        report[ISSUE_METADATA_FILE_INCOMPLETE].append(
-            f'{metadata_file_path}/METADATA does not has "third_party.version"')
-
-      for tag in package_metadata.third_party.security.tag:
-        if not tag.startswith(NVD_CPE23):
-          report[ISSUE_UNKNOWN_SECURITY_TAG_TYPE].append(
-              f'Unknown security tag type: {tag} in {metadata_file_path}/METADATA')
-  else:
-    report[ISSUE_NO_METADATA_FILE].append(
-        "installed_file: {}, module_path: {}".format(
-            installed_file_metadata['installed_file'], installed_file_metadata['module_path']))
-
-
-def generate_fragment():
-  with open(args.metadata, newline='') as sbom_metadata_file:
-    reader = csv.DictReader(sbom_metadata_file)
-    for installed_file_metadata in reader:
-      installed_file = installed_file_metadata['installed_file']
-      if args.output_file != args.product_out_dir + installed_file + ".spdx":
-        continue
-
-      module_path = installed_file_metadata['module_path']
-      package_id = new_package_id(encode_for_spdxid(module_path), PKG_PREBUILT)
-      package = new_package_record(package_id, module_path, args.build_version, args.product_mfr)
-      file_id = new_file_id(installed_file)
-      file = new_file_record(file_id, installed_file, checksum(installed_file))
-      relationship = new_relationship_record(file_id, REL_GENERATED_FROM, package_id)
-      records = [package, file, relationship]
-      write_tagvalue_sbom(records)
-      break
-
-
-def main():
-  global args
-  args = get_args()
-  log('Args:', vars(args))
-
-  if args.unbundled:
-    generate_fragment()
-    return
-
-  global metadata_file_protos
-  metadata_file_protos = {}
-
-  doc_id = 'SPDXRef-DOCUMENT'
-  doc_header = new_doc_header(doc_id)
-
-  product_package_id = 'SPDXRef-PRODUCT'
-  product_package = new_package_record(product_package_id, 'PRODUCT', args.build_version, args.product_mfr,
-                                       files_analyzed='true')
-
-  platform_package_id = 'SPDXRef-PLATFORM'
-  platform_package = new_package_record(platform_package_id, 'PLATFORM', args.build_version, args.product_mfr)
-
-  # Report on some issues and information
-  report = {
-    ISSUE_NO_METADATA: [],
-    ISSUE_NO_METADATA_FILE: [],
-    ISSUE_METADATA_FILE_INCOMPLETE: [],
-    ISSUE_UNKNOWN_SECURITY_TAG_TYPE: [],
-    ISSUE_INSTALLED_FILE_NOT_EXIST: [],
-    INFO_METADATA_FOUND_FOR_PACKAGE: [],
-  }
-
-  # Scan the metadata in CSV file and create the corresponding package and file records in SPDX
-  product_files = []
-  package_ids = []
-  package_records = []
-  rels_file_gen_from = []
-  with open(args.metadata, newline='') as sbom_metadata_file:
-    reader = csv.DictReader(sbom_metadata_file)
-    for installed_file_metadata in reader:
-      installed_file = installed_file_metadata['installed_file']
-      module_path = installed_file_metadata['module_path']
-      product_copy_files = installed_file_metadata['product_copy_files']
-      kernel_module_copy_files = installed_file_metadata['kernel_module_copy_files']
-
-      if not installed_file_has_metadata(installed_file_metadata, report):
-        continue
-      file_path = args.product_out_dir + '/' + installed_file
-      if not (os.path.islink(file_path) or os.path.isfile(file_path)):
-        report[ISSUE_INSTALLED_FILE_NOT_EXIST].append(installed_file)
-        continue
-
-      file_id = new_file_id(installed_file)
-      product_files.append(new_file_record(file_id, installed_file, checksum(installed_file)))
-
-      if is_source_package(installed_file_metadata) or is_prebuilt_package(installed_file_metadata):
-        metadata_file_path = get_metadata_file_path(installed_file_metadata)
-        report_metadata_file(metadata_file_path, installed_file_metadata, report)
-
-        # File from source fork packages or prebuilt fork packages
-        external_doc_ref, pkgs, rels = get_sbom_fragments(installed_file_metadata, metadata_file_path)
-        if len(pkgs) > 0:
-          if external_doc_ref and external_doc_ref not in doc_header[EXTERNAL_DOCUMENT_REF]:
-            doc_header[EXTERNAL_DOCUMENT_REF].append(external_doc_ref)
-          for p in pkgs:
-            if not p[SPDXID] in package_ids:
-              package_ids.append(p[SPDXID])
-              package_records.append(p)
-          for rel in rels:
-            if not rel in package_records:
-              package_records.append(rel)
-          fork_package_id = pkgs[0][SPDXID]  # The first package should be the source/prebuilt fork package
-          rels_file_gen_from.append(new_relationship_record(file_id, REL_GENERATED_FROM, fork_package_id))
-      elif module_path or installed_file_metadata['is_platform_generated']:
-        # File from PLATFORM package
-        rels_file_gen_from.append(new_relationship_record(file_id, REL_GENERATED_FROM, platform_package_id))
-      elif product_copy_files:
-        # Format of product_copy_files: <source path>:<dest path>
-        src_path = product_copy_files.split(':')[0]
-        # So far product_copy_files are copied from directory system, kernel, hardware, frameworks and device,
-        # so process them as files from PLATFORM package
-        rels_file_gen_from.append(new_relationship_record(file_id, REL_GENERATED_FROM, platform_package_id))
-      elif installed_file.endswith('.fsv_meta'):
-        # See build/make/core/Makefile:2988
-        rels_file_gen_from.append(new_relationship_record(file_id, REL_GENERATED_FROM, platform_package_id))
-      elif kernel_module_copy_files.startswith('ANDROID-GEN'):
-        # For the four files generated for _dlkm, _ramdisk partitions
-        # See build/make/core/Makefile:323
-        rels_file_gen_from.append(new_relationship_record(file_id, REL_GENERATED_FROM, platform_package_id))
-
-  product_package[PACKAGE_VERIFICATION_CODE] = generate_package_verification_code(product_files)
-
-  all_records = [
-      doc_header,
-      product_package,
-      new_relationship_record(doc_id, REL_DESCRIBES, product_package_id),
-  ]
-  all_records += product_files
-  all_records.append(platform_package)
-  all_records += package_records
-  rels_file_gen_from.sort(key=sort_rels)
-  all_records += rels_file_gen_from
-
-  # Save SBOM records to output file
-  doc_header[CREATED] = datetime.datetime.now(tz=datetime.timezone.utc).strftime('%Y-%m-%dT%H:%M:%SZ')
-  write_tagvalue_sbom(all_records)
-  if args.json:
-    write_json_sbom(all_records, product_package_id)
-
-  save_report(report)
-
-
-if __name__ == '__main__':
-  main()
diff --git a/tools/sbom/Android.bp b/tools/sbom/Android.bp
new file mode 100644
index 0000000..f6c0190
--- /dev/null
+++ b/tools/sbom/Android.bp
@@ -0,0 +1,53 @@
+// Copyright (C) 2023 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+python_binary_host {
+    name: "generate-sbom",
+    srcs: [
+        "generate-sbom.py",
+    ],
+    version: {
+        py3: {
+            embedded_launcher: true,
+        },
+    },
+    libs: [
+        "metadata_file_proto_py",
+        "libprotobuf-python",
+        "sbom_lib",
+    ],
+}
+
+python_library_host {
+    name: "sbom_lib",
+    srcs: [
+        "sbom_data.py",
+        "sbom_writers.py",
+    ],
+}
+
+python_test_host {
+    name: "sbom_writers_test",
+    main: "sbom_writers_test.py",
+    srcs: [
+        "sbom_writers_test.py",
+    ],
+    data: [
+        "testdata/*",
+    ],
+    libs: [
+        "sbom_lib",
+    ],
+    test_suites: ["general-tests"],
+}
diff --git a/tools/sbom/generate-sbom.py b/tools/sbom/generate-sbom.py
new file mode 100755
index 0000000..0c5deb2
--- /dev/null
+++ b/tools/sbom/generate-sbom.py
@@ -0,0 +1,536 @@
+#!/usr/bin/env python3
+#
+# Copyright (C) 2023 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""
+Generate the SBOM of the current target product in SPDX format.
+Usage example:
+  generate-sbom.py --output_file out/target/product/vsoc_x86_64/sbom.spdx \
+                   --metadata out/target/product/vsoc_x86_64/sbom-metadata.csv \
+                   --product_out_dir=out/target/product/vsoc_x86_64 \
+                   --build_version $(cat out/target/product/vsoc_x86_64/build_fingerprint.txt) \
+                   --product_mfr=Google
+"""
+
+import argparse
+import csv
+import datetime
+import google.protobuf.text_format as text_format
+import hashlib
+import os
+import metadata_file_pb2
+import sbom_data
+import sbom_writers
+
+
+# Package type
+PKG_SOURCE = 'SOURCE'
+PKG_UPSTREAM = 'UPSTREAM'
+PKG_PREBUILT = 'PREBUILT'
+
+# Security tag
+NVD_CPE23 = 'NVD-CPE2.3:'
+
+# Report
+ISSUE_NO_METADATA = 'No metadata generated in Make for installed files:'
+ISSUE_NO_METADATA_FILE = 'No METADATA file found for installed file:'
+ISSUE_METADATA_FILE_INCOMPLETE = 'METADATA file incomplete:'
+ISSUE_UNKNOWN_SECURITY_TAG_TYPE = 'Unknown security tag type:'
+ISSUE_INSTALLED_FILE_NOT_EXIST = 'Non-exist installed files:'
+INFO_METADATA_FOUND_FOR_PACKAGE = 'METADATA file found for packages:'
+
+
+def get_args():
+  parser = argparse.ArgumentParser()
+  parser.add_argument('-v', '--verbose', action='store_true', default=False, help='Print more information.')
+  parser.add_argument('--output_file', required=True, help='The generated SBOM file in SPDX format.')
+  parser.add_argument('--metadata', required=True, help='The SBOM metadata file path.')
+  parser.add_argument('--product_out_dir', required=True, help='The parent directory of all the installed files.')
+  parser.add_argument('--build_version', required=True, help='The build version.')
+  parser.add_argument('--product_mfr', required=True, help='The product manufacturer.')
+  parser.add_argument('--json', action='store_true', default=False, help='Generated SBOM file in SPDX JSON format')
+  parser.add_argument('--unbundled', action='store_true', default=False, help='Generate SBOM file for unbundled module')
+
+  return parser.parse_args()
+
+
+def log(*info):
+  if args.verbose:
+    for i in info:
+      print(i)
+
+
+def encode_for_spdxid(s):
+  """Simple encode for string values used in SPDXID which uses the charset of A-Za-Z0-9.-"""
+  result = ''
+  for c in s:
+    if c.isalnum() or c in '.-':
+      result += c
+    elif c in '_@/':
+      result += '-'
+    else:
+      result += '0x' + c.encode('utf-8').hex()
+
+  return result.lstrip('-')
+
+
+def new_package_id(package_name, type):
+  return f'SPDXRef-{type}-{encode_for_spdxid(package_name)}'
+
+
+def new_file_id(file_path):
+  return f'SPDXRef-{encode_for_spdxid(file_path)}'
+
+
+def checksum(file_path):
+  file_path = args.product_out_dir + '/' + file_path
+  h = hashlib.sha1()
+  if os.path.islink(file_path):
+    h.update(os.readlink(file_path).encode('utf-8'))
+  else:
+    with open(file_path, 'rb') as f:
+      h.update(f.read())
+  return f'SHA1: {h.hexdigest()}'
+
+
+def is_soong_prebuilt_module(file_metadata):
+  return file_metadata['soong_module_type'] and file_metadata['soong_module_type'] in [
+      'android_app_import', 'android_library_import', 'cc_prebuilt_binary', 'cc_prebuilt_library',
+      'cc_prebuilt_library_headers', 'cc_prebuilt_library_shared', 'cc_prebuilt_library_static', 'cc_prebuilt_object',
+      'dex_import', 'java_import', 'java_sdk_library_import', 'java_system_modules_import',
+      'libclang_rt_prebuilt_library_static', 'libclang_rt_prebuilt_library_shared', 'llvm_prebuilt_library_static',
+      'ndk_prebuilt_object', 'ndk_prebuilt_shared_stl', 'nkd_prebuilt_static_stl', 'prebuilt_apex',
+      'prebuilt_bootclasspath_fragment', 'prebuilt_dsp', 'prebuilt_firmware', 'prebuilt_kernel_modules',
+      'prebuilt_rfsa', 'prebuilt_root', 'rust_prebuilt_dylib', 'rust_prebuilt_library', 'rust_prebuilt_rlib',
+      'vndk_prebuilt_shared',
+
+      # 'android_test_import',
+      # 'cc_prebuilt_test_library_shared',
+      # 'java_import_host',
+      # 'java_test_import',
+      # 'llvm_host_prebuilt_library_shared',
+      # 'prebuilt_apis',
+      # 'prebuilt_build_tool',
+      # 'prebuilt_defaults',
+      # 'prebuilt_etc',
+      # 'prebuilt_etc_host',
+      # 'prebuilt_etc_xml',
+      # 'prebuilt_font',
+      # 'prebuilt_hidl_interfaces',
+      # 'prebuilt_platform_compat_config',
+      # 'prebuilt_stubs_sources',
+      # 'prebuilt_usr_share',
+      # 'prebuilt_usr_share_host',
+      # 'soong_config_module_type_import',
+  ]
+
+
+def is_source_package(file_metadata):
+  module_path = file_metadata['module_path']
+  return module_path.startswith('external/') and not is_prebuilt_package(file_metadata)
+
+
+def is_prebuilt_package(file_metadata):
+  module_path = file_metadata['module_path']
+  if module_path:
+    return (module_path.startswith('prebuilts/') or
+            is_soong_prebuilt_module(file_metadata) or
+            file_metadata['is_prebuilt_make_module'])
+
+  kernel_module_copy_files = file_metadata['kernel_module_copy_files']
+  if kernel_module_copy_files and not kernel_module_copy_files.startswith('ANDROID-GEN:'):
+    return True
+
+  return False
+
+
+def get_source_package_info(file_metadata, metadata_file_path):
+  """Return source package info exists in its METADATA file, currently including name, security tag
+  and external SBOM reference.
+
+  See go/android-spdx and go/android-sbom-gen for more details.
+  """
+  if not metadata_file_path:
+    return file_metadata['module_path'], []
+
+  metadata_proto = metadata_file_protos[metadata_file_path]
+  external_refs = []
+  for tag in metadata_proto.third_party.security.tag:
+    if tag.lower().startswith((NVD_CPE23 + 'cpe:2.3:').lower()):
+      external_refs.append(
+        sbom_data.PackageExternalRef(category=sbom_data.PackageExternalRefCategory.SECURITY,
+                                     type=sbom_data.PackageExternalRefType.cpe23Type,
+                                     locator=tag.removeprefix(NVD_CPE23)))
+    elif tag.lower().startswith((NVD_CPE23 + 'cpe:/').lower()):
+      external_refs.append(
+        sbom_data.PackageExternalRef(category=sbom_data.PackageExternalRefCategory.SECURITY,
+                                     type=sbom_data.PackageExternalRefType.cpe22Type,
+                                     locator=tag.removeprefix(NVD_CPE23)))
+
+  if metadata_proto.name:
+    return metadata_proto.name, external_refs
+  else:
+    return os.path.basename(metadata_file_path), external_refs  # return the directory name only as package name
+
+
+def get_prebuilt_package_name(file_metadata, metadata_file_path):
+  """Return name of a prebuilt package, which can be from the METADATA file, metadata file path,
+  module path or kernel module's source path if the installed file is a kernel module.
+
+  See go/android-spdx and go/android-sbom-gen for more details.
+  """
+  name = None
+  if metadata_file_path:
+    metadata_proto = metadata_file_protos[metadata_file_path]
+    if metadata_proto.name:
+      name = metadata_proto.name
+    else:
+      name = metadata_file_path
+  elif file_metadata['module_path']:
+    name = file_metadata['module_path']
+  elif file_metadata['kernel_module_copy_files']:
+    src_path = file_metadata['kernel_module_copy_files'].split(':')[0]
+    name = os.path.dirname(src_path)
+
+  return name.removeprefix('prebuilts/').replace('/', '-')
+
+
+def get_metadata_file_path(file_metadata):
+  """Search for METADATA file of a package and return its path."""
+  metadata_path = ''
+  if file_metadata['module_path']:
+    metadata_path = file_metadata['module_path']
+  elif file_metadata['kernel_module_copy_files']:
+    metadata_path = os.path.dirname(file_metadata['kernel_module_copy_files'].split(':')[0])
+
+  while metadata_path and not os.path.exists(metadata_path + '/METADATA'):
+    metadata_path = os.path.dirname(metadata_path)
+
+  return metadata_path
+
+
+def get_package_version(metadata_file_path):
+  """Return a package's version in its METADATA file."""
+  if not metadata_file_path:
+    return None
+  metadata_proto = metadata_file_protos[metadata_file_path]
+  return metadata_proto.third_party.version
+
+
+def get_package_homepage(metadata_file_path):
+  """Return a package's homepage URL in its METADATA file."""
+  if not metadata_file_path:
+    return None
+  metadata_proto = metadata_file_protos[metadata_file_path]
+  if metadata_proto.third_party.homepage:
+    return metadata_proto.third_party.homepage
+  for url in metadata_proto.third_party.url:
+    if url.type == metadata_file_pb2.URL.Type.HOMEPAGE:
+      return url.value
+
+  return None
+
+
+def get_package_download_location(metadata_file_path):
+  """Return a package's code repository URL in its METADATA file."""
+  if not metadata_file_path:
+    return None
+  metadata_proto = metadata_file_protos[metadata_file_path]
+  if metadata_proto.third_party.url:
+    urls = sorted(metadata_proto.third_party.url, key=lambda url: url.type)
+    if urls[0].type != metadata_file_pb2.URL.Type.HOMEPAGE:
+      return urls[0].value
+    elif len(urls) > 1:
+      return urls[1].value
+
+  return None
+
+
+def get_sbom_fragments(installed_file_metadata, metadata_file_path):
+  """Return SPDX fragment of source/prebuilt packages, which usually contains a SOURCE/PREBUILT
+  package, a UPSTREAM package if it's a source package and a external SBOM document reference if
+  it's a prebuilt package with sbom_ref defined in its METADATA file.
+
+  See go/android-spdx and go/android-sbom-gen for more details.
+  """
+  external_doc_ref = None
+  packages = []
+  relationships = []
+
+  # Info from METADATA file
+  homepage = get_package_homepage(metadata_file_path)
+  version = get_package_version(metadata_file_path)
+  download_location = get_package_download_location(metadata_file_path)
+
+  if is_source_package(installed_file_metadata):
+    # Source fork packages
+    name, external_refs = get_source_package_info(installed_file_metadata, metadata_file_path)
+    source_package_id = new_package_id(name, PKG_SOURCE)
+    source_package = sbom_data.Package(id=source_package_id, name=name, version=args.build_version,
+                                       supplier='Organization: ' + args.product_mfr,
+                                       external_refs=external_refs)
+
+    upstream_package_id = new_package_id(name, PKG_UPSTREAM)
+    upstream_package = sbom_data.Package(id=upstream_package_id, name=name, version=version,
+                                         supplier='Organization: ' + homepage if homepage else None,
+                                         download_location=download_location)
+    packages += [source_package, upstream_package]
+    relationships.append(sbom_data.Relationship(id1=source_package_id,
+                                                relationship=sbom_data.RelationshipType.VARIANT_OF,
+                                                id2=upstream_package_id))
+  elif is_prebuilt_package(installed_file_metadata):
+    # Prebuilt fork packages
+    name = get_prebuilt_package_name(installed_file_metadata, metadata_file_path)
+    prebuilt_package_id = new_package_id(name, PKG_PREBUILT)
+    prebuilt_package = sbom_data.Package(id=prebuilt_package_id,
+                                         name=name,
+                                         version=args.build_version,
+                                         supplier='Organization: ' + args.product_mfr)
+    packages.append(prebuilt_package)
+
+    if metadata_file_path:
+      metadata_proto = metadata_file_protos[metadata_file_path]
+      if metadata_proto.third_party.WhichOneof('sbom') == 'sbom_ref':
+        sbom_url = metadata_proto.third_party.sbom_ref.url
+        sbom_checksum = metadata_proto.third_party.sbom_ref.checksum
+        upstream_element_id = metadata_proto.third_party.sbom_ref.element_id
+        if sbom_url and sbom_checksum and upstream_element_id:
+          doc_ref_id = f'DocumentRef-{PKG_UPSTREAM}-{encode_for_spdxid(name)}'
+          external_doc_ref = sbom_data.DocumentExternalReference(id=doc_ref_id,
+                                                                 uri=sbom_url,
+                                                                 checksum=sbom_checksum)
+          relationships.append(
+            sbom_data.Relationship(id1=prebuilt_package_id,
+                                   relationship=sbom_data.RelationshipType.VARIANT_OF,
+                                   id2=doc_ref_id + ':' + upstream_element_id))
+
+  return external_doc_ref, packages, relationships
+
+
+def generate_package_verification_code(files):
+  checksums = [file.checksum for file in files]
+  checksums.sort()
+  h = hashlib.sha1()
+  h.update(''.join(checksums).encode(encoding='utf-8'))
+  return h.hexdigest()
+
+
+def save_report(report):
+  prefix, _ = os.path.splitext(args.output_file)
+  with open(prefix + '-gen-report.txt', 'w', encoding='utf-8') as report_file:
+    for type, issues in report.items():
+      report_file.write(type + '\n')
+      for issue in issues:
+        report_file.write('\t' + issue + '\n')
+      report_file.write('\n')
+
+
+# Validate the metadata generated by Make for installed files and report if there is no metadata.
+def installed_file_has_metadata(installed_file_metadata, report):
+  installed_file = installed_file_metadata['installed_file']
+  module_path = installed_file_metadata['module_path']
+  product_copy_files = installed_file_metadata['product_copy_files']
+  kernel_module_copy_files = installed_file_metadata['kernel_module_copy_files']
+  is_platform_generated = installed_file_metadata['is_platform_generated']
+
+  if (not module_path and
+      not product_copy_files and
+      not kernel_module_copy_files and
+      not is_platform_generated and
+      not installed_file.endswith('.fsv_meta')):
+    report[ISSUE_NO_METADATA].append(installed_file)
+    return False
+
+  return True
+
+
+def report_metadata_file(metadata_file_path, installed_file_metadata, report):
+  if metadata_file_path:
+    report[INFO_METADATA_FOUND_FOR_PACKAGE].append(
+        'installed_file: {}, module_path: {}, METADATA file: {}'.format(
+            installed_file_metadata['installed_file'],
+            installed_file_metadata['module_path'],
+            metadata_file_path + '/METADATA'))
+
+    package_metadata = metadata_file_pb2.Metadata()
+    with open(metadata_file_path + '/METADATA', 'rt') as f:
+      text_format.Parse(f.read(), package_metadata)
+
+    if not metadata_file_path in metadata_file_protos:
+      metadata_file_protos[metadata_file_path] = package_metadata
+      if not package_metadata.name:
+        report[ISSUE_METADATA_FILE_INCOMPLETE].append(f'{metadata_file_path}/METADATA does not has "name"')
+
+      if not package_metadata.third_party.version:
+        report[ISSUE_METADATA_FILE_INCOMPLETE].append(
+            f'{metadata_file_path}/METADATA does not has "third_party.version"')
+
+      for tag in package_metadata.third_party.security.tag:
+        if not tag.startswith(NVD_CPE23):
+          report[ISSUE_UNKNOWN_SECURITY_TAG_TYPE].append(
+              f'Unknown security tag type: {tag} in {metadata_file_path}/METADATA')
+  else:
+    report[ISSUE_NO_METADATA_FILE].append(
+        "installed_file: {}, module_path: {}".format(
+            installed_file_metadata['installed_file'], installed_file_metadata['module_path']))
+
+
+def generate_sbom_for_unbundled():
+  with open(args.metadata, newline='') as sbom_metadata_file:
+    reader = csv.DictReader(sbom_metadata_file)
+    doc = sbom_data.Document(name=args.build_version,
+                             namespace=f'https://www.google.com/sbom/spdx/android/{args.build_version}',
+                             creators=['Organization: ' + args.product_mfr])
+    for installed_file_metadata in reader:
+      installed_file = installed_file_metadata['installed_file']
+      if args.output_file != args.product_out_dir + installed_file + ".spdx":
+        continue
+
+      module_path = installed_file_metadata['module_path']
+      package_id = new_package_id(module_path, PKG_PREBUILT)
+      package = sbom_data.Package(id=package_id,
+                                  name=module_path,
+                                  version=args.build_version,
+                                  supplier='Organization: ' + args.product_mfr)
+      file_id = new_file_id(installed_file)
+      file = sbom_data.File(id=file_id, name=installed_file, checksum=checksum(installed_file))
+      relationship = sbom_data.Relationship(id1=file_id,
+                                            relationship=sbom_data.RelationshipType.GENERATED_FROM,
+                                            id2=package_id)
+      doc.add_package(package)
+      doc.files.append(file)
+      doc.describes = file_id
+      doc.add_relationship(relationship)
+      doc.created = datetime.datetime.now(tz=datetime.timezone.utc).strftime('%Y-%m-%dT%H:%M:%SZ')
+      break
+
+  with open(args.output_file, 'w', encoding="utf-8") as file:
+    sbom_writers.TagValueWriter.write(doc, file, fragment=True)
+
+
+def main():
+  global args
+  args = get_args()
+  log('Args:', vars(args))
+
+  if args.unbundled:
+    generate_sbom_for_unbundled()
+    return
+
+  global metadata_file_protos
+  metadata_file_protos = {}
+
+  doc = sbom_data.Document(name=args.build_version,
+                           namespace=f'https://www.google.com/sbom/spdx/android/{args.build_version}',
+                           creators=['Organization: ' + args.product_mfr])
+
+  product_package = sbom_data.Package(id=sbom_data.SPDXID_PRODUCT,
+                                      name=sbom_data.PACKAGE_NAME_PRODUCT,
+                                      version=args.build_version,
+                                      supplier='Organization: ' + args.product_mfr,
+                                      files_analyzed=True)
+  doc.packages.append(product_package)
+
+  doc.packages.append(sbom_data.Package(id=sbom_data.SPDXID_PLATFORM,
+                                        name=sbom_data.PACKAGE_NAME_PLATFORM,
+                                        version=args.build_version,
+                                        supplier='Organization: ' + args.product_mfr))
+
+  # Report on some issues and information
+  report = {
+    ISSUE_NO_METADATA: [],
+    ISSUE_NO_METADATA_FILE: [],
+    ISSUE_METADATA_FILE_INCOMPLETE: [],
+    ISSUE_UNKNOWN_SECURITY_TAG_TYPE: [],
+    ISSUE_INSTALLED_FILE_NOT_EXIST: [],
+    INFO_METADATA_FOUND_FOR_PACKAGE: [],
+  }
+
+  # Scan the metadata in CSV file and create the corresponding package and file records in SPDX
+  with open(args.metadata, newline='') as sbom_metadata_file:
+    reader = csv.DictReader(sbom_metadata_file)
+    for installed_file_metadata in reader:
+      installed_file = installed_file_metadata['installed_file']
+      module_path = installed_file_metadata['module_path']
+      product_copy_files = installed_file_metadata['product_copy_files']
+      kernel_module_copy_files = installed_file_metadata['kernel_module_copy_files']
+
+      if not installed_file_has_metadata(installed_file_metadata, report):
+        continue
+      file_path = args.product_out_dir + '/' + installed_file
+      if not (os.path.islink(file_path) or os.path.isfile(file_path)):
+        report[ISSUE_INSTALLED_FILE_NOT_EXIST].append(installed_file)
+        continue
+
+      file_id = new_file_id(installed_file)
+      doc.files.append(
+        sbom_data.File(id=file_id, name=installed_file, checksum=checksum(installed_file)))
+      product_package.file_ids.append(file_id)
+
+      if is_source_package(installed_file_metadata) or is_prebuilt_package(installed_file_metadata):
+        metadata_file_path = get_metadata_file_path(installed_file_metadata)
+        report_metadata_file(metadata_file_path, installed_file_metadata, report)
+
+        # File from source fork packages or prebuilt fork packages
+        external_doc_ref, pkgs, rels = get_sbom_fragments(installed_file_metadata, metadata_file_path)
+        if len(pkgs) > 0:
+          if external_doc_ref:
+            doc.add_external_ref(external_doc_ref)
+          for p in pkgs:
+            doc.add_package(p)
+          for rel in rels:
+            doc.add_relationship(rel)
+          fork_package_id = pkgs[0].id  # The first package should be the source/prebuilt fork package
+          doc.add_relationship(sbom_data.Relationship(id1=file_id,
+                                                      relationship=sbom_data.RelationshipType.GENERATED_FROM,
+                                                      id2=fork_package_id))
+      elif module_path or installed_file_metadata['is_platform_generated']:
+        # File from PLATFORM package
+        doc.add_relationship(sbom_data.Relationship(id1=file_id,
+                                                    relationship=sbom_data.RelationshipType.GENERATED_FROM,
+                                                    id2=sbom_data.SPDXID_PLATFORM))
+      elif product_copy_files:
+        # Format of product_copy_files: <source path>:<dest path>
+        src_path = product_copy_files.split(':')[0]
+        # So far product_copy_files are copied from directory system, kernel, hardware, frameworks and device,
+        # so process them as files from PLATFORM package
+        doc.add_relationship(sbom_data.Relationship(id1=file_id,
+                                                    relationship=sbom_data.RelationshipType.GENERATED_FROM,
+                                                    id2=sbom_data.SPDXID_PLATFORM))
+      elif installed_file.endswith('.fsv_meta'):
+        # See build/make/core/Makefile:2988
+        doc.add_relationship(sbom_data.Relationship(id1=file_id,
+                                                    relationship=sbom_data.RelationshipType.GENERATED_FROM,
+                                                    id2=sbom_data.SPDXID_PLATFORM))
+      elif kernel_module_copy_files.startswith('ANDROID-GEN'):
+        # For the four files generated for _dlkm, _ramdisk partitions
+        # See build/make/core/Makefile:323
+        doc.add_relationship(sbom_data.Relationship(id1=file_id,
+                                                    relationship=sbom_data.RelationshipType.GENERATED_FROM,
+                                                    id2=sbom_data.SPDXID_PLATFORM))
+
+  product_package.verification_code = generate_package_verification_code(doc.files)
+
+  # Save SBOM records to output file
+  doc.created = datetime.datetime.now(tz=datetime.timezone.utc).strftime('%Y-%m-%dT%H:%M:%SZ')
+  with open(args.output_file, 'w', encoding="utf-8") as file:
+    sbom_writers.TagValueWriter.write(doc, file)
+  if args.json:
+    with open(args.output_file+'.json', 'w', encoding="utf-8") as file:
+      sbom_writers.JSONWriter.write(doc, file)
+
+
+if __name__ == '__main__':
+  main()
diff --git a/tools/sbom/sbom_data.py b/tools/sbom/sbom_data.py
new file mode 100644
index 0000000..0c380f6
--- /dev/null
+++ b/tools/sbom/sbom_data.py
@@ -0,0 +1,120 @@
+#!/usr/bin/env python3
+#
+# Copyright (C) 2023 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""
+Define data classes that model SBOMs defined by SPDX. The data classes could be
+written out to different formats (tagvalue, JSON, etc) of SPDX with corresponding
+writer utilities.
+
+Rrefer to SPDX 2.3 spec: https://spdx.github.io/spdx-spec/v2.3/ and go/android-spdx for details of
+fields in each data class.
+"""
+
+from dataclasses import dataclass, field
+from typing import List
+
+SPDXID_DOC = 'SPDXRef-DOCUMENT'
+SPDXID_PRODUCT = 'SPDXRef-PRODUCT'
+SPDXID_PLATFORM = 'SPDXRef-PLATFORM'
+
+PACKAGE_NAME_PRODUCT = 'PRODUCT'
+PACKAGE_NAME_PLATFORM = 'PLATFORM'
+
+
+class PackageExternalRefCategory:
+  SECURITY = 'SECURITY'
+  PACKAGE_MANAGER = 'PACKAGE-MANAGER'
+  PERSISTENT_ID = 'PERSISTENT-ID'
+  OTHER = 'OTHER'
+
+
+class PackageExternalRefType:
+  cpe22Type = 'cpe22Type'
+  cpe23Type = 'cpe23Type'
+
+
+@dataclass
+class PackageExternalRef:
+  category: PackageExternalRefCategory
+  type: PackageExternalRefType
+  locator: str
+
+
+@dataclass
+class Package:
+  name: str
+  id: str
+  version: str = None
+  supplier: str = None
+  download_location: str = None
+  files_analyzed: bool = False
+  verification_code: str = None
+  file_ids: List[str] = field(default_factory=list)
+  external_refs: List[PackageExternalRef] = field(default_factory=list)
+
+
+@dataclass
+class File:
+  id: str
+  name: str
+  checksum: str
+
+
+class RelationshipType:
+  DESCRIBES = 'DESCRIBES'
+  VARIANT_OF = 'VARIANT_OF'
+  GENERATED_FROM = 'GENERATED_FROM'
+
+
+@dataclass
+class Relationship:
+  id1: str
+  relationship: RelationshipType
+  id2: str
+
+
+@dataclass
+class DocumentExternalReference:
+  id: str
+  uri: str
+  checksum: str
+
+
+@dataclass
+class Document:
+  name: str
+  namespace: str
+  id: str = SPDXID_DOC
+  describes: str = SPDXID_PRODUCT
+  creators: List[str] = field(default_factory=list)
+  created: str = None
+  external_refs: List[DocumentExternalReference] = field(default_factory=list)
+  packages: List[Package] = field(default_factory=list)
+  files: List[File] = field(default_factory=list)
+  relationships: List[Relationship] = field(default_factory=list)
+
+  def add_external_ref(self, external_ref):
+    if not any(external_ref.uri == ref.uri for ref in self.external_refs):
+      self.external_refs.append(external_ref)
+
+  def add_package(self, package):
+    if not any(package.id == p.id for p in self.packages):
+      self.packages.append(package)
+
+  def add_relationship(self, rel):
+    if not any(rel.id1 == r.id1 and rel.id2 == r.id2 and rel.relationship == r.relationship
+               for r in self.relationships):
+      self.relationships.append(rel)
diff --git a/tools/sbom/sbom_writers.py b/tools/sbom/sbom_writers.py
new file mode 100644
index 0000000..66aa6b4
--- /dev/null
+++ b/tools/sbom/sbom_writers.py
@@ -0,0 +1,365 @@
+#!/usr/bin/env python3
+#
+# Copyright (C) 2023 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""
+Serialize objects defined in package sbom_data to SPDX format: tagvalue, JSON.
+"""
+
+import json
+import sbom_data
+
+SPDX_VER = 'SPDX-2.3'
+DATA_LIC = 'CC0-1.0'
+
+
+class Tags:
+  # Common
+  SPDXID = 'SPDXID'
+  SPDX_VERSION = 'SPDXVersion'
+  DATA_LICENSE = 'DataLicense'
+  DOCUMENT_NAME = 'DocumentName'
+  DOCUMENT_NAMESPACE = 'DocumentNamespace'
+  CREATED = 'Created'
+  CREATOR = 'Creator'
+  EXTERNAL_DOCUMENT_REF = 'ExternalDocumentRef'
+
+  # Package
+  PACKAGE_NAME = 'PackageName'
+  PACKAGE_DOWNLOAD_LOCATION = 'PackageDownloadLocation'
+  PACKAGE_VERSION = 'PackageVersion'
+  PACKAGE_SUPPLIER = 'PackageSupplier'
+  FILES_ANALYZED = 'FilesAnalyzed'
+  PACKAGE_VERIFICATION_CODE = 'PackageVerificationCode'
+  PACKAGE_EXTERNAL_REF = 'ExternalRef'
+  # Package license
+  PACKAGE_LICENSE_CONCLUDED = 'PackageLicenseConcluded'
+  PACKAGE_LICENSE_INFO_FROM_FILES = 'PackageLicenseInfoFromFiles'
+  PACKAGE_LICENSE_DECLARED = 'PackageLicenseDeclared'
+  PACKAGE_LICENSE_COMMENTS = 'PackageLicenseComments'
+
+  # File
+  FILE_NAME = 'FileName'
+  FILE_CHECKSUM = 'FileChecksum'
+  # File license
+  FILE_LICENSE_CONCLUDED = 'LicenseConcluded'
+  FILE_LICENSE_INFO_IN_FILE = 'LicenseInfoInFile'
+  FILE_LICENSE_COMMENTS = 'LicenseComments'
+  FILE_COPYRIGHT_TEXT = 'FileCopyrightText'
+  FILE_NOTICE = 'FileNotice'
+  FILE_ATTRIBUTION_TEXT = 'FileAttributionText'
+
+  # Relationship
+  RELATIONSHIP = 'Relationship'
+
+
+class TagValueWriter:
+  @staticmethod
+  def marshal_doc_headers(sbom_doc):
+    headers = [
+      f'{Tags.SPDX_VERSION}: {SPDX_VER}',
+      f'{Tags.DATA_LICENSE}: {DATA_LIC}',
+      f'{Tags.SPDXID}: {sbom_doc.id}',
+      f'{Tags.DOCUMENT_NAME}: {sbom_doc.name}',
+      f'{Tags.DOCUMENT_NAMESPACE}: {sbom_doc.namespace}',
+    ]
+    for creator in sbom_doc.creators:
+      headers.append(f'{Tags.CREATOR}: {creator}')
+    headers.append(f'{Tags.CREATED}: {sbom_doc.created}')
+    for doc_ref in sbom_doc.external_refs:
+      headers.append(
+        f'{Tags.EXTERNAL_DOCUMENT_REF}: {doc_ref.id} {doc_ref.uri} {doc_ref.checksum}')
+    headers.append('')
+    return headers
+
+  @staticmethod
+  def marshal_package(package):
+    download_location = 'NONE'
+    if package.download_location:
+      download_location = package.download_location
+    tagvalues = [
+      f'{Tags.PACKAGE_NAME}: {package.name}',
+      f'{Tags.SPDXID}: {package.id}',
+      f'{Tags.PACKAGE_DOWNLOAD_LOCATION}: {download_location}',
+      f'{Tags.FILES_ANALYZED}: {str(package.files_analyzed).lower()}',
+    ]
+    if package.version:
+      tagvalues.append(f'{Tags.PACKAGE_VERSION}: {package.version}')
+    if package.supplier:
+      tagvalues.append(f'{Tags.PACKAGE_SUPPLIER}: {package.supplier}')
+    if package.verification_code:
+      tagvalues.append(f'{Tags.PACKAGE_VERIFICATION_CODE}: {package.verification_code}')
+    if package.external_refs:
+      for external_ref in package.external_refs:
+        tagvalues.append(
+          f'{Tags.PACKAGE_EXTERNAL_REF}: {external_ref.category} {external_ref.type} {external_ref.locator}')
+
+    tagvalues.append('')
+    return tagvalues
+
+  @staticmethod
+  def marshal_described_element(sbom_doc):
+    if not sbom_doc.describes:
+      return None
+
+    product_package = [p for p in sbom_doc.packages if p.id == sbom_doc.describes]
+    if product_package:
+      tagvalues = TagValueWriter.marshal_package(product_package[0])
+      tagvalues.append(
+        f'{Tags.RELATIONSHIP}: {sbom_doc.id} {sbom_data.RelationshipType.DESCRIBES} {sbom_doc.describes}')
+
+      tagvalues.append('')
+      return tagvalues
+
+    file = [f for f in sbom_doc.files if f.id == sbom_doc.describes]
+    if file:
+      tagvalues = [
+        f'{Tags.RELATIONSHIP}: {sbom_doc.id} {sbom_data.RelationshipType.DESCRIBES} {sbom_doc.describes}'
+      ]
+
+      return tagvalues
+
+    return None
+
+  @staticmethod
+  def marshal_packages(sbom_doc):
+    tagvalues = []
+    marshaled_relationships = []
+    i = 0
+    packages = sbom_doc.packages
+    while i < len(packages):
+      if packages[i].id == sbom_doc.describes:
+        i += 1
+        continue
+
+      if i + 1 < len(packages) \
+          and packages[i].id.startswith('SPDXRef-SOURCE-') \
+          and packages[i + 1].id.startswith('SPDXRef-UPSTREAM-'):
+        tagvalues += TagValueWriter.marshal_package(packages[i])
+        tagvalues += TagValueWriter.marshal_package(packages[i + 1])
+        rel = next((r for r in sbom_doc.relationships if
+                    r.id1 == packages[i].id and
+                    r.id2 == packages[i + 1].id and
+                    r.relationship == sbom_data.RelationshipType.VARIANT_OF), None)
+        if rel:
+          marshaled_relationships.append(rel)
+          tagvalues.append(TagValueWriter.marshal_relationship(rel))
+          tagvalues.append('')
+
+        i += 2
+      else:
+        tagvalues += TagValueWriter.marshal_package(packages[i])
+        i += 1
+
+    return tagvalues, marshaled_relationships
+
+  @staticmethod
+  def marshal_file(file):
+    tagvalues = [
+      f'{Tags.FILE_NAME}: {file.name}',
+      f'{Tags.SPDXID}: {file.id}',
+      f'{Tags.FILE_CHECKSUM}: {file.checksum}',
+      '',
+    ]
+
+    return tagvalues
+
+  @staticmethod
+  def marshal_files(sbom_doc):
+    tagvalues = []
+    for file in sbom_doc.files:
+      tagvalues += TagValueWriter.marshal_file(file)
+    return tagvalues
+
+  @staticmethod
+  def marshal_relationship(rel):
+    return f'{Tags.RELATIONSHIP}: {rel.id1} {rel.relationship} {rel.id2}'
+
+  @staticmethod
+  def marshal_relationships(sbom_doc, marshaled_rels):
+    tagvalues = []
+    sorted_rels = sorted(sbom_doc.relationships, key=lambda r: r.id2 + r.id1)
+    for rel in sorted_rels:
+      if any(r.id1 == rel.id1 and r.id2 == rel.id2 and r.relationship == rel.relationship
+             for r in marshaled_rels):
+        continue
+      tagvalues.append(TagValueWriter.marshal_relationship(rel))
+    tagvalues.append('')
+    return tagvalues
+
+  @staticmethod
+  def write(sbom_doc, file, fragment=False):
+    content = []
+    if not fragment:
+      content += TagValueWriter.marshal_doc_headers(sbom_doc)
+      described_element = TagValueWriter.marshal_described_element(sbom_doc)
+      if described_element:
+        content += described_element
+    content += TagValueWriter.marshal_files(sbom_doc)
+    tagvalues, marshaled_relationships = TagValueWriter.marshal_packages(sbom_doc)
+    content += tagvalues
+    content += TagValueWriter.marshal_relationships(sbom_doc, marshaled_relationships)
+    file.write('\n'.join(content))
+
+
+class PropNames:
+  # Common
+  SPDXID = 'SPDXID'
+  SPDX_VERSION = 'spdxVersion'
+  DATA_LICENSE = 'dataLicense'
+  NAME = 'name'
+  DOCUMENT_NAMESPACE = 'documentNamespace'
+  CREATION_INFO = 'creationInfo'
+  CREATORS = 'creators'
+  CREATED = 'created'
+  EXTERNAL_DOCUMENT_REF = 'externalDocumentRefs'
+  DOCUMENT_DESCRIBES = 'documentDescribes'
+  EXTERNAL_DOCUMENT_ID = 'externalDocumentId'
+  EXTERNAL_DOCUMENT_URI = 'spdxDocument'
+  EXTERNAL_DOCUMENT_CHECKSUM = 'checksum'
+  ALGORITHM = 'algorithm'
+  CHECKSUM_VALUE = 'checksumValue'
+
+  # Package
+  PACKAGES = 'packages'
+  PACKAGE_DOWNLOAD_LOCATION = 'downloadLocation'
+  PACKAGE_VERSION = 'versionInfo'
+  PACKAGE_SUPPLIER = 'supplier'
+  FILES_ANALYZED = 'filesAnalyzed'
+  PACKAGE_VERIFICATION_CODE = 'packageVerificationCode'
+  PACKAGE_VERIFICATION_CODE_VALUE = 'packageVerificationCodeValue'
+  PACKAGE_EXTERNAL_REFS = 'externalRefs'
+  PACKAGE_EXTERNAL_REF_CATEGORY = 'referenceCategory'
+  PACKAGE_EXTERNAL_REF_TYPE = 'referenceType'
+  PACKAGE_EXTERNAL_REF_LOCATOR = 'referenceLocator'
+  PACKAGE_HAS_FILES = 'hasFiles'
+
+  # File
+  FILES = 'files'
+  FILE_NAME = 'fileName'
+  FILE_CHECKSUMS = 'checksums'
+
+  # Relationship
+  RELATIONSHIPS = 'relationships'
+  REL_ELEMENT_ID = 'spdxElementId'
+  REL_RELATED_ELEMENT_ID = 'relatedSpdxElement'
+  REL_TYPE = 'relationshipType'
+
+
+class JSONWriter:
+  @staticmethod
+  def marshal_doc_headers(sbom_doc):
+    headers = {
+      PropNames.SPDX_VERSION: SPDX_VER,
+      PropNames.DATA_LICENSE: DATA_LIC,
+      PropNames.SPDXID: sbom_doc.id,
+      PropNames.NAME: sbom_doc.name,
+      PropNames.DOCUMENT_NAMESPACE: sbom_doc.namespace,
+      PropNames.CREATION_INFO: {}
+    }
+    creators = [creator for creator in sbom_doc.creators]
+    headers[PropNames.CREATION_INFO][PropNames.CREATORS] = creators
+    headers[PropNames.CREATION_INFO][PropNames.CREATED] = sbom_doc.created
+    external_refs = []
+    for doc_ref in sbom_doc.external_refs:
+      checksum = doc_ref.checksum.split(': ')
+      external_refs.append({
+        PropNames.EXTERNAL_DOCUMENT_ID: f'{doc_ref.id}',
+        PropNames.EXTERNAL_DOCUMENT_URI: doc_ref.uri,
+        PropNames.EXTERNAL_DOCUMENT_CHECKSUM: {
+          PropNames.ALGORITHM: checksum[0],
+          PropNames.CHECKSUM_VALUE: checksum[1]
+        }
+      })
+    if external_refs:
+      headers[PropNames.EXTERNAL_DOCUMENT_REF] = external_refs
+    headers[PropNames.DOCUMENT_DESCRIBES] = [sbom_doc.describes]
+
+    return headers
+
+  @staticmethod
+  def marshal_packages(sbom_doc):
+    packages = []
+    for p in sbom_doc.packages:
+      package = {
+        PropNames.NAME: p.name,
+        PropNames.SPDXID: p.id,
+        PropNames.PACKAGE_DOWNLOAD_LOCATION: p.download_location if p.download_location else 'NONE',
+        PropNames.FILES_ANALYZED: p.files_analyzed
+      }
+      if p.version:
+        package[PropNames.PACKAGE_VERSION] = p.version
+      if p.supplier:
+        package[PropNames.PACKAGE_SUPPLIER] = p.supplier
+      if p.verification_code:
+        package[PropNames.PACKAGE_VERIFICATION_CODE] = {
+          PropNames.PACKAGE_VERIFICATION_CODE_VALUE: p.verification_code
+        }
+      if p.external_refs:
+        package[PropNames.PACKAGE_EXTERNAL_REFS] = []
+        for ref in p.external_refs:
+          ext_ref = {
+            PropNames.PACKAGE_EXTERNAL_REF_CATEGORY: ref.category,
+            PropNames.PACKAGE_EXTERNAL_REF_TYPE: ref.type,
+            PropNames.PACKAGE_EXTERNAL_REF_LOCATOR: ref.locator,
+          }
+          package[PropNames.PACKAGE_EXTERNAL_REFS].append(ext_ref)
+      if p.file_ids:
+        package[PropNames.PACKAGE_HAS_FILES] = []
+        for file_id in p.file_ids:
+          package[PropNames.PACKAGE_HAS_FILES].append(file_id)
+
+      packages.append(package)
+
+    return {PropNames.PACKAGES: packages}
+
+  @staticmethod
+  def marshal_files(sbom_doc):
+    files = []
+    for f in sbom_doc.files:
+      file = {
+        PropNames.FILE_NAME: f.name,
+        PropNames.SPDXID: f.id
+      }
+      checksum = f.checksum.split(': ')
+      file[PropNames.FILE_CHECKSUMS] = [{
+        PropNames.ALGORITHM: checksum[0],
+        PropNames.CHECKSUM_VALUE: checksum[1],
+      }]
+      files.append(file)
+    return {PropNames.FILES: files}
+
+  @staticmethod
+  def marshal_relationships(sbom_doc):
+    relationships = []
+    sorted_rels = sorted(sbom_doc.relationships, key=lambda r: r.relationship + r.id2 + r.id1)
+    for r in sorted_rels:
+      rel = {
+        PropNames.REL_ELEMENT_ID: r.id1,
+        PropNames.REL_RELATED_ELEMENT_ID: r.id2,
+        PropNames.REL_TYPE: r.relationship,
+      }
+      relationships.append(rel)
+
+    return {PropNames.RELATIONSHIPS: relationships}
+
+  @staticmethod
+  def write(sbom_doc, file):
+    doc = {}
+    doc.update(JSONWriter.marshal_doc_headers(sbom_doc))
+    doc.update(JSONWriter.marshal_packages(sbom_doc))
+    doc.update(JSONWriter.marshal_files(sbom_doc))
+    doc.update(JSONWriter.marshal_relationships(sbom_doc))
+    file.write(json.dumps(doc, indent=4))
diff --git a/tools/sbom/sbom_writers_test.py b/tools/sbom/sbom_writers_test.py
new file mode 100644
index 0000000..4db2bb7
--- /dev/null
+++ b/tools/sbom/sbom_writers_test.py
@@ -0,0 +1,153 @@
+#!/usr/bin/env python3
+#
+# Copyright (C) 2023 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import io
+import pathlib
+import unittest
+import sbom_data
+import sbom_writers
+
+BUILD_FINGER_PRINT = 'build_finger_print'
+SUPPLIER_GOOGLE = 'Organization: Google'
+SUPPLIER_UPSTREAM = 'Organization: upstream'
+
+SPDXID_PREBUILT_PACKAGE1 = 'SPDXRef-PREBUILT-package1'
+SPDXID_SOURCE_PACKAGE1 = 'SPDXRef-SOURCE-package1'
+SPDXID_UPSTREAM_PACKAGE1 = 'SPDXRef-UPSTREAM-package1'
+
+SPDXID_FILE1 = 'SPDXRef-file1'
+SPDXID_FILE2 = 'SPDXRef-file2'
+SPDXID_FILE3 = 'SPDXRef-file3'
+
+
+class SBOMWritersTest(unittest.TestCase):
+
+  def setUp(self):
+    # SBOM of a product
+    self.sbom_doc = sbom_data.Document(name='test doc',
+                                       namespace='http://www.google.com/sbom/spdx/android',
+                                       creators=[SUPPLIER_GOOGLE],
+                                       created='2023-03-31T22:17:58Z',
+                                       describes=sbom_data.SPDXID_PRODUCT)
+    self.sbom_doc.add_external_ref(
+      sbom_data.DocumentExternalReference(id='DocumentRef-external_doc_ref',
+                                          uri='external_doc_uri',
+                                          checksum='SHA1: 1234567890'))
+    self.sbom_doc.add_package(
+      sbom_data.Package(id=sbom_data.SPDXID_PRODUCT,
+                        name=sbom_data.PACKAGE_NAME_PRODUCT,
+                        supplier=SUPPLIER_GOOGLE,
+                        version=BUILD_FINGER_PRINT,
+                        files_analyzed=True,
+                        verification_code='123456',
+                        file_ids=[SPDXID_FILE1, SPDXID_FILE2, SPDXID_FILE3]))
+
+    self.sbom_doc.add_package(
+      sbom_data.Package(id=sbom_data.SPDXID_PLATFORM,
+                        name=sbom_data.PACKAGE_NAME_PLATFORM,
+                        supplier=SUPPLIER_GOOGLE,
+                        version=BUILD_FINGER_PRINT,
+                        ))
+
+    self.sbom_doc.add_package(
+      sbom_data.Package(id=SPDXID_PREBUILT_PACKAGE1,
+                        name='Prebuilt package1',
+                        supplier=SUPPLIER_GOOGLE,
+                        version=BUILD_FINGER_PRINT,
+                        ))
+
+    self.sbom_doc.add_package(
+      sbom_data.Package(id=SPDXID_SOURCE_PACKAGE1,
+                        name='Source package1',
+                        supplier=SUPPLIER_GOOGLE,
+                        version=BUILD_FINGER_PRINT,
+                        external_refs=[sbom_data.PackageExternalRef(
+                          category=sbom_data.PackageExternalRefCategory.SECURITY,
+                          type=sbom_data.PackageExternalRefType.cpe22Type,
+                          locator='cpe:/a:jsoncpp_project:jsoncpp:1.9.4')]
+                        ))
+
+    self.sbom_doc.add_package(
+      sbom_data.Package(id=SPDXID_UPSTREAM_PACKAGE1,
+                        name='Upstream package1',
+                        supplier=SUPPLIER_UPSTREAM,
+                        version='1.1',
+                        ))
+
+    self.sbom_doc.add_relationship(sbom_data.Relationship(id1=SPDXID_SOURCE_PACKAGE1,
+                                                          relationship=sbom_data.RelationshipType.VARIANT_OF,
+                                                          id2=SPDXID_UPSTREAM_PACKAGE1))
+
+    self.sbom_doc.files.append(
+      sbom_data.File(id=SPDXID_FILE1, name='/bin/file1', checksum='SHA1: 11111'))
+    self.sbom_doc.files.append(
+      sbom_data.File(id=SPDXID_FILE2, name='/bin/file2', checksum='SHA1: 22222'))
+    self.sbom_doc.files.append(
+      sbom_data.File(id=SPDXID_FILE3, name='/bin/file3', checksum='SHA1: 33333'))
+
+    self.sbom_doc.add_relationship(sbom_data.Relationship(id1=SPDXID_FILE1,
+                                                          relationship=sbom_data.RelationshipType.GENERATED_FROM,
+                                                          id2=sbom_data.SPDXID_PLATFORM))
+    self.sbom_doc.add_relationship(sbom_data.Relationship(id1=SPDXID_FILE2,
+                                                          relationship=sbom_data.RelationshipType.GENERATED_FROM,
+                                                          id2=SPDXID_PREBUILT_PACKAGE1))
+    self.sbom_doc.add_relationship(sbom_data.Relationship(id1=SPDXID_FILE3,
+                                                          relationship=sbom_data.RelationshipType.GENERATED_FROM,
+                                                          id2=SPDXID_SOURCE_PACKAGE1
+                                                          ))
+
+    # SBOM fragment of a APK
+    self.unbundled_sbom_doc = sbom_data.Document(name='test doc',
+                                                 namespace='http://www.google.com/sbom/spdx/android',
+                                                 creators=[SUPPLIER_GOOGLE],
+                                                 created='2023-03-31T22:17:58Z',
+                                                 describes=SPDXID_FILE1)
+
+    self.unbundled_sbom_doc.files.append(
+      sbom_data.File(id=SPDXID_FILE1, name='/bin/file1.apk', checksum='SHA1: 11111'))
+    self.unbundled_sbom_doc.add_package(
+      sbom_data.Package(id=SPDXID_SOURCE_PACKAGE1,
+                        name='Unbundled apk package',
+                        supplier=SUPPLIER_GOOGLE,
+                        version=BUILD_FINGER_PRINT))
+    self.unbundled_sbom_doc.add_relationship(sbom_data.Relationship(id1=SPDXID_FILE1,
+                                                                    relationship=sbom_data.RelationshipType.GENERATED_FROM,
+                                                                    id2=SPDXID_SOURCE_PACKAGE1))
+
+  def test_tagvalue_writer(self):
+    with io.StringIO() as output:
+      sbom_writers.TagValueWriter.write(self.sbom_doc, output)
+      expected_output = pathlib.Path('testdata/expected_tagvalue_sbom.spdx').read_text()
+      self.maxDiff = None
+      self.assertEqual(expected_output, output.getvalue())
+
+  def test_tagvalue_writer_unbundled(self):
+    with io.StringIO() as output:
+      sbom_writers.TagValueWriter.write(self.unbundled_sbom_doc, output, fragment=True)
+      expected_output = pathlib.Path('testdata/expected_tagvalue_sbom_unbundled.spdx').read_text()
+      self.maxDiff = None
+      self.assertEqual(expected_output, output.getvalue())
+
+  def test_json_writer(self):
+    with io.StringIO() as output:
+      sbom_writers.JSONWriter.write(self.sbom_doc, output)
+      expected_output = pathlib.Path('testdata/expected_json_sbom.spdx.json').read_text()
+      self.maxDiff = None
+      self.assertEqual(expected_output, output.getvalue())
+
+
+if __name__ == '__main__':
+  unittest.main(verbosity=2)
diff --git a/tools/sbom/testdata/expected_json_sbom.spdx.json b/tools/sbom/testdata/expected_json_sbom.spdx.json
new file mode 100644
index 0000000..628615f
--- /dev/null
+++ b/tools/sbom/testdata/expected_json_sbom.spdx.json
@@ -0,0 +1,137 @@
+{
+    "spdxVersion": "SPDX-2.3",
+    "dataLicense": "CC0-1.0",
+    "SPDXID": "SPDXRef-DOCUMENT",
+    "name": "test doc",
+    "documentNamespace": "http://www.google.com/sbom/spdx/android",
+    "creationInfo": {
+        "creators": [
+            "Organization: Google"
+        ],
+        "created": "2023-03-31T22:17:58Z"
+    },
+    "externalDocumentRefs": [
+        {
+            "externalDocumentId": "DocumentRef-external_doc_ref",
+            "spdxDocument": "external_doc_uri",
+            "checksum": {
+                "algorithm": "SHA1",
+                "checksumValue": "1234567890"
+            }
+        }
+    ],
+    "documentDescribes": [
+        "SPDXRef-PRODUCT"
+    ],
+    "packages": [
+        {
+            "name": "PRODUCT",
+            "SPDXID": "SPDXRef-PRODUCT",
+            "downloadLocation": "NONE",
+            "filesAnalyzed": true,
+            "versionInfo": "build_finger_print",
+            "supplier": "Organization: Google",
+            "packageVerificationCode": {
+                "packageVerificationCodeValue": "123456"
+            },
+            "hasFiles": [
+                "SPDXRef-file1",
+                "SPDXRef-file2",
+                "SPDXRef-file3"
+            ]
+        },
+        {
+            "name": "PLATFORM",
+            "SPDXID": "SPDXRef-PLATFORM",
+            "downloadLocation": "NONE",
+            "filesAnalyzed": false,
+            "versionInfo": "build_finger_print",
+            "supplier": "Organization: Google"
+        },
+        {
+            "name": "Prebuilt package1",
+            "SPDXID": "SPDXRef-PREBUILT-package1",
+            "downloadLocation": "NONE",
+            "filesAnalyzed": false,
+            "versionInfo": "build_finger_print",
+            "supplier": "Organization: Google"
+        },
+        {
+            "name": "Source package1",
+            "SPDXID": "SPDXRef-SOURCE-package1",
+            "downloadLocation": "NONE",
+            "filesAnalyzed": false,
+            "versionInfo": "build_finger_print",
+            "supplier": "Organization: Google",
+            "externalRefs": [
+                {
+                    "referenceCategory": "SECURITY",
+                    "referenceType": "cpe22Type",
+                    "referenceLocator": "cpe:/a:jsoncpp_project:jsoncpp:1.9.4"
+                }
+            ]
+        },
+        {
+            "name": "Upstream package1",
+            "SPDXID": "SPDXRef-UPSTREAM-package1",
+            "downloadLocation": "NONE",
+            "filesAnalyzed": false,
+            "versionInfo": "1.1",
+            "supplier": "Organization: upstream"
+        }
+    ],
+    "files": [
+        {
+            "fileName": "/bin/file1",
+            "SPDXID": "SPDXRef-file1",
+            "checksums": [
+                {
+                    "algorithm": "SHA1",
+                    "checksumValue": "11111"
+                }
+            ]
+        },
+        {
+            "fileName": "/bin/file2",
+            "SPDXID": "SPDXRef-file2",
+            "checksums": [
+                {
+                    "algorithm": "SHA1",
+                    "checksumValue": "22222"
+                }
+            ]
+        },
+        {
+            "fileName": "/bin/file3",
+            "SPDXID": "SPDXRef-file3",
+            "checksums": [
+                {
+                    "algorithm": "SHA1",
+                    "checksumValue": "33333"
+                }
+            ]
+        }
+    ],
+    "relationships": [
+        {
+            "spdxElementId": "SPDXRef-file1",
+            "relatedSpdxElement": "SPDXRef-PLATFORM",
+            "relationshipType": "GENERATED_FROM"
+        },
+        {
+            "spdxElementId": "SPDXRef-file2",
+            "relatedSpdxElement": "SPDXRef-PREBUILT-package1",
+            "relationshipType": "GENERATED_FROM"
+        },
+        {
+            "spdxElementId": "SPDXRef-file3",
+            "relatedSpdxElement": "SPDXRef-SOURCE-package1",
+            "relationshipType": "GENERATED_FROM"
+        },
+        {
+            "spdxElementId": "SPDXRef-SOURCE-package1",
+            "relatedSpdxElement": "SPDXRef-UPSTREAM-package1",
+            "relationshipType": "VARIANT_OF"
+        }
+    ]
+}
\ No newline at end of file
diff --git a/tools/sbom/testdata/expected_tagvalue_sbom.spdx b/tools/sbom/testdata/expected_tagvalue_sbom.spdx
new file mode 100644
index 0000000..0f1c6f8
--- /dev/null
+++ b/tools/sbom/testdata/expected_tagvalue_sbom.spdx
@@ -0,0 +1,65 @@
+SPDXVersion: SPDX-2.3
+DataLicense: CC0-1.0
+SPDXID: SPDXRef-DOCUMENT
+DocumentName: test doc
+DocumentNamespace: http://www.google.com/sbom/spdx/android
+Creator: Organization: Google
+Created: 2023-03-31T22:17:58Z
+ExternalDocumentRef: DocumentRef-external_doc_ref external_doc_uri SHA1: 1234567890
+
+PackageName: PRODUCT
+SPDXID: SPDXRef-PRODUCT
+PackageDownloadLocation: NONE
+FilesAnalyzed: true
+PackageVersion: build_finger_print
+PackageSupplier: Organization: Google
+PackageVerificationCode: 123456
+
+Relationship: SPDXRef-DOCUMENT DESCRIBES SPDXRef-PRODUCT
+
+FileName: /bin/file1
+SPDXID: SPDXRef-file1
+FileChecksum: SHA1: 11111
+
+FileName: /bin/file2
+SPDXID: SPDXRef-file2
+FileChecksum: SHA1: 22222
+
+FileName: /bin/file3
+SPDXID: SPDXRef-file3
+FileChecksum: SHA1: 33333
+
+PackageName: PLATFORM
+SPDXID: SPDXRef-PLATFORM
+PackageDownloadLocation: NONE
+FilesAnalyzed: false
+PackageVersion: build_finger_print
+PackageSupplier: Organization: Google
+
+PackageName: Prebuilt package1
+SPDXID: SPDXRef-PREBUILT-package1
+PackageDownloadLocation: NONE
+FilesAnalyzed: false
+PackageVersion: build_finger_print
+PackageSupplier: Organization: Google
+
+PackageName: Source package1
+SPDXID: SPDXRef-SOURCE-package1
+PackageDownloadLocation: NONE
+FilesAnalyzed: false
+PackageVersion: build_finger_print
+PackageSupplier: Organization: Google
+ExternalRef: SECURITY cpe22Type cpe:/a:jsoncpp_project:jsoncpp:1.9.4
+
+PackageName: Upstream package1
+SPDXID: SPDXRef-UPSTREAM-package1
+PackageDownloadLocation: NONE
+FilesAnalyzed: false
+PackageVersion: 1.1
+PackageSupplier: Organization: upstream
+
+Relationship: SPDXRef-SOURCE-package1 VARIANT_OF SPDXRef-UPSTREAM-package1
+
+Relationship: SPDXRef-file1 GENERATED_FROM SPDXRef-PLATFORM
+Relationship: SPDXRef-file2 GENERATED_FROM SPDXRef-PREBUILT-package1
+Relationship: SPDXRef-file3 GENERATED_FROM SPDXRef-SOURCE-package1
diff --git a/tools/sbom/testdata/expected_tagvalue_sbom_unbundled.spdx b/tools/sbom/testdata/expected_tagvalue_sbom_unbundled.spdx
new file mode 100644
index 0000000..a00c291
--- /dev/null
+++ b/tools/sbom/testdata/expected_tagvalue_sbom_unbundled.spdx
@@ -0,0 +1,12 @@
+FileName: /bin/file1.apk
+SPDXID: SPDXRef-file1
+FileChecksum: SHA1: 11111
+
+PackageName: Unbundled apk package
+SPDXID: SPDXRef-SOURCE-package1
+PackageDownloadLocation: NONE
+FilesAnalyzed: false
+PackageVersion: build_finger_print
+PackageSupplier: Organization: Google
+
+Relationship: SPDXRef-file1 GENERATED_FROM SPDXRef-SOURCE-package1