reidentify_text_fpe.py

# Copyright 2023 Google LLC
#
# 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.

"""Uses of the Data Loss Prevention API for deidentifying sensitive data."""

from __future__ import annotations

import argparse


# [START dlp_reidentify_text_fpe]
import base64

import google.cloud.dlp


def reidentify_text_with_fpe(
    project: str,
    input_str: str,
    key_name: str = None,
    wrapped_key: str = None,
) -> None:
    """
    Uses the Data Loss Prevention API to re-identify sensitive data in a
    string using Format Preserving Encryption (FPE).
    Args:
        project: The Google Cloud project id to use as a parent resource.
        input_str: The string to re-identify (will be treated as text).
        key_name: The name of the Cloud KMS key used to encrypt ('wrap') the
            AES-256 key. Example:
            key_name = 'projects/YOUR_GCLOUD_PROJECT/locations/YOUR_LOCATION/
            keyRings/YOUR_KEYRING_NAME/cryptoKeys/YOUR_KEY_NAME'
        wrapped_key: The encrypted ('wrapped') AES-256 key to use. This key
            should be encrypted using the Cloud KMS key specified by key_name.
    """

    # Instantiate a client.
    dlp = google.cloud.dlp_v2.DlpServiceClient()

    # The wrapped key is base64-encoded, but the library expects a binary
    # string, so decode it here.
    wrapped_key = base64.b64decode(wrapped_key)

    # Specify the type of info the inspection will re-identify.
    # This must use the same custom infoType that was used as a
    # surrogate during the initial encryption.
    surrogate_info_type = {"name": "PHONE_NUMBER"}

    # Construct FPE configuration dictionary
    crypto_replace_ffx_fpe_config = {
        "crypto_key": {
            "kms_wrapped": {"wrapped_key": wrapped_key, "crypto_key_name": key_name}
        },
        "common_alphabet": "NUMERIC",
        "surrogate_info_type": surrogate_info_type,
    }

    # Construct re-identify configuration dictionary
    reidentify_config = {
        "info_type_transformations": {
            "transformations": [
                {
                    "primitive_transformation": {
                        "crypto_replace_ffx_fpe_config": crypto_replace_ffx_fpe_config,
                    },
                    "info_types": [surrogate_info_type],
                }
            ]
        }
    }

    # Construct inspect configuration dictionary
    inspect_config = {
        "custom_info_types": [{"info_type": surrogate_info_type, "surrogate_type": {}}]
    }

    # Construct the `item`.
    item = {"value": input_str}

    # Convert the project id into a full resource id.
    parent = f"projects/{project}/locations/global"

    # Call the API.
    response = dlp.reidentify_content(
        request={
            "parent": parent,
            "reidentify_config": reidentify_config,
            "inspect_config": inspect_config,
            "item": item,
        }
    )

    # Print results
    print(f"Text after re-identification: {response.item.value}")


# [END dlp_reidentify_text_fpe]

if __name__ == "__main__":
    parser = argparse.ArgumentParser(description=__doc__)

    parser.add_argument(
        "project",
        help="The Google Cloud project id to use as a parent resource.",
    )
    parser.add_argument(
        "item",
        help="The string to deidentify. " "Example: string = 'My SSN is 372819127'",
    )
    parser.add_argument(
        "key_name",
        help="The name of the Cloud KMS key used to encrypt ('wrap') the "
        "AES-256 key. Example: "
        "key_name = 'projects/YOUR_GCLOUD_PROJECT/locations/YOUR_LOCATION/"
        "keyRings/YOUR_KEYRING_NAME/cryptoKeys/YOUR_KEY_NAME'",
    )
    parser.add_argument(
        "wrapped_key",
        help="The encrypted ('wrapped') AES-256 key to use. This key should "
        "be encrypted using the Cloud KMS key specified by key_name.",
    )

    args = parser.parse_args()

    reidentify_text_with_fpe(
        args.project,
        args.item,
        wrapped_key=args.wrapped_key,
        key_name=args.key_name,
    )