Name Date Size #Lines LOC

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BUILD.bazelH A D25-Apr-20251.7 KiB4743

GcsEnvelopeAeadExample.javaH A D25-Apr-20257.4 KiB192118

README.mdH A D25-Apr-20252.7 KiB8460

gcs_envelope_aead_example_test.shH A D25-Apr-20252.5 KiB8440

README.md

1# Java Google Cloud Storage (GCS) client-side encryption example
2
3This example shows how to encrypt/decrypt GCS blobs with Tink using
4[Envelope Encryption](https://cloud.google.com/kms/docs/envelope-encryption).
5
6It shows how you can use Tink to encrypt data with a newly generated *data
7encryption key* (DEK) which is wrapped with a KMS key. The data will be
8encrypted with AES256 GCM using the DEK and the DEK will be encrypted with the
9KMS key and stored alongside the ciphertext in GCS.
10
11The CLI takes the following required arguments:
12
13*   mode: "encrypt" or "decrypt" to indicate if you want to encrypt or decrypt.
14*   kek-uri: The URI for the Cloud KMS key to be used for envelope encryption.
15*   gcp-credential-file: Name of the file with the Google Cloud Platform (GCP)
16    credentials (in JSON format) that can access the Cloud KMS key and the GCS
17    input/output blobs.
18*   gcp-project-id: The ID of the GCP project hosting the GCS blobs that you
19    want to encrypt or decrypt.
20
21When mode is "encrypt", it takes the following additional arguments:
22
23*   local-input-file: Read the plaintext from this local file.
24*   gcs-output-blob: Write the encryption result to this blob in GCS. The
25    encryption result is bound to the location of this blob. That is, if you
26    rename or move it to a different bucket, decryption will fail.
27
28When mode is "decrypt", it takes the following additional arguments:
29
30*   gcs-input-blob: Read the ciphertext from this blob in GCS.
31*   local-output-file: Write the decryption result to this local file.
32
33`gcs-input-blob` and `gcs-output-blob` have this format:
34`gs://my-bucket-name/my-object-name`.
35
36## Build and Run
37
38### Prequisite
39
40This envelope encryption example uses a Cloud KMS key as a key-encryption key
41(KEK). In order to run it, you need to:
42
43*   Create a symmetric key on Cloud KMS. Copy the key URI which is in this
44    format:
45    `projects/<my-project>/locations/global/keyRings/<my-key-ring>/cryptoKeys/<my-key>`.
46
47*   Create a bucket on GCS.
48
49*   Create and download a service account that is allowed to encrypt and decrypt
50    with the Cloud KMS key, and read/write to the GCS bucket.
51
52### Bazel
53
54```shell
55git clone https://github.com/google/tink
56cd tink/examples/java_src
57bazel build ...
58```
59
60Encrypt a file and upload it to GCS:
61
62```shell
63echo "some data" > testdata.txt
64
65./bazel-bin/gcs/gcs_envelope_aead_example \
66    encrypt \
67    gcp-kms://my-cloud-kms-key-uri \
68    my-service-account.json \
69    my-gcp-project-id \
70    testdata.txt gs://my-bucket-name/my-blob-name
71
72```
73
74Download a file from GCS and decrypt it:
75
76```shell
77./bazel-bin/gcs/gcs_envelope_aead_example \
78    decrypt \
79    gcp-kms://my-key-uri \
80    my-service-account.json \
81    my-gcp-project-id \
82    gs://my-bucket-name/my-blob-name testdata.txt.decrypted
83```
84