Azure SDK for Java Reference Documentation

Current version is 12.18.0, click here for the index

Azure Storage Blobs Cryptography client library for Java

Azure Blob storage is Microsoft's object storage solution for the cloud. Blob storage is optimized for storing massive amounts of unstructured data. Unstructured data is data that does not adhere to a particular data model or definition, such as text or binary data. This package supports client side encryption for blob storage.

Source code | API reference documentation | REST API documentation | Product documentation | Samples

Getting started

Prerequisites

Include the package

Include the BOM file

Please include the azure-sdk-bom to your project to take dependency on GA version of the library. In the following snippet, replace the {bomversionto_target} placeholder with the version number. To learn more about the BOM, see the AZURE SDK BOM README.

<dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>com.azure</groupId>
            <artifactId>azure-sdk-bom</artifactId>
            <version>{bom_version_to_target}</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>
    </dependencies>
</dependencyManagement>

and then include the direct dependency in the dependencies section without the version tag.

<dependencies>
  <dependency>
    <groupId>com.azure</groupId>
    <artifactId>azure-storage-blob-cryptography</artifactId>
  </dependency>
</dependencies>

Include direct dependency

If you want to take dependency on a particular version of the library that is not present in the BOM, add the direct dependency to your project as follows.

<dependency>
  <groupId>com.azure</groupId>
  <artifactId>azure-storage-blob-cryptography</artifactId>
  <version>12.18.0</version>
</dependency>

Create a Storage Account

To create a Storage Account you can use the Azure Portal or Azure CLI.

az storage account create \
    --resource-group <resource-group-name> \
    --name <storage-account-name> \
    --location <location>

Authenticate the client

In order to interact with the Storage service (Blob, Queue, Message, MessageId, File) you'll need to create an instance of the Service Client class. To make this possible you'll need the Account SAS (shared access signature) string of Storage account. Learn more at SAS Token

Get credentials

  • SAS Token

a. Use the Azure CLI snippet below to get the SAS token from the Storage Account.

az storage blob generate-sas \
    --account-name {Storage Account name} \
    --container-name {container name} \
    --name {blob name} \
    --permissions {permissions to grant} \
    --expiry {datetime to expire the SAS token} \
    --services {storage services the SAS allows} \
    --resource-types {resource types the SAS allows}

Example:

CONNECTION_STRING=<connection-string>

az storage blob generate-sas \
    --account-name MyStorageAccount \
    --container-name MyContainer \
    --name MyBlob \
    --permissions racdw \
    --expiry 2020-06-15

b. Alternatively, get the Account SAS Token from the Azure Portal.

  1. Go to your Storage Account
  2. Select Shared access signature from the menu on the left
  3. Click on Generate SAS and connection string (after setup)
Shared Key Credential

a. Use Account name and Account key. Account name is your Storage Account name.

  1. Go to your Storage Account
  2. Select Access keys from the menu on the left
  3. Under key1/key2 copy the contents of the Key field

or

b. Use the connection string.

  1. Go to your Storage Account
  2. Select Access keys from the menu on the left
  3. Under key1/key2 copy the contents of the Connection string field

Key concepts

Blob storage is designed for:

  • Serving images or documents directly to a browser.
  • Storing files for distributed access.
  • Streaming video and audio.
  • Writing to log files.
  • Storing data for backup and restore, disaster recovery, and archiving.
  • Storing data for analysis by an on-premises or Azure-hosted service.

Examples

Note: The usage of the EncryptedBlobClient is the same as the equivalent BlobClient, the only difference being client construction. Please refer to azure-storage-blob for common use cases of the BlobClient

The following sections provide several code snippets covering some of the most common Azure Storage Blob cryptography creation tasks, including:

Create an EncryptedBlobClient from a BlobClient

Create an EncryptedBlobClient using a BlobClient. BlobClient construction is explained in the azure-storage-blob README.

EncryptedBlobClient client = new EncryptedBlobClientBuilder()
    .key(key, keyWrapAlgorithm)
    .keyResolver(keyResolver)
    .blobClient(blobClient)
    .buildEncryptedBlobClient();

Create an EncryptedBlobClient

Create a BlobServiceClient using a connection string.

EncryptedBlobClient client = new EncryptedBlobClientBuilder()
    .key(key, keyWrapAlgorithm)
    .keyResolver(keyResolver)
    .connectionString(connectionString)
    .containerName(containerName)
    .blobName(blobName)
    .buildEncryptedBlobClient();

Use a local KeyEncryptionKey

JsonWebKey localKey = JsonWebKey.fromAes(new SecretKeySpec(keyBytes, secretKeyAlgorithm),
    Arrays.asList(KeyOperation.WRAP_KEY, KeyOperation.UNWRAP_KEY))
    .setId("my-id");
AsyncKeyEncryptionKey akek = new KeyEncryptionKeyClientBuilder()
    .buildAsyncKeyEncryptionKey(localKey).block();

EncryptedBlobClient client = new EncryptedBlobClientBuilder()
    .key(akek, keyWrapAlgorithm)
    .connectionString(connectionString)
    .containerName(containerName)
    .blobName(blobName)
    .buildEncryptedBlobClient();

Use a KeyVaultKey

KeyClient keyClient = new KeyClientBuilder()
    .vaultUrl(keyVaultUrl)
    .credential(tokenCredential)
    .buildClient();
KeyVaultKey rsaKey = keyClient.createRsaKey(new CreateRsaKeyOptions(keyName)
    .setExpiresOn(OffsetDateTime.now().plusYears(1))
    .setKeySize(2048));
AsyncKeyEncryptionKey akek = new KeyEncryptionKeyClientBuilder()
    .credential(tokenCredential)
    .buildAsyncKeyEncryptionKey(rsaKey.getId())
    .block();

EncryptedBlobClient client = new EncryptedBlobClientBuilder()
    .key(akek, keyWrapAlgorithm)
    .connectionString(connectionString)
    .containerName(containerName)
    .blobName(blobName)
    .buildEncryptedBlobClient();

Troubleshooting

When interacting with blobs using this Java client library, errors returned by the service correspond to the same HTTP status codes returned for REST API requests. For example, if you try to retrieve a container or blob that doesn't exist in your Storage Account, a 404 error is returned, indicating Not Found.

Default HTTP Client

All client libraries by default use the Netty HTTP client. Adding the above dependency will automatically configure the client library to use the Netty HTTP client. Configuring or changing the HTTP client is detailed in the HTTP clients wiki.

Default SSL library

All client libraries, by default, use the Tomcat-native Boring SSL library to enable native-level performance for SSL operations. The Boring SSL library is an uber jar containing native libraries for Linux / macOS / Windows, and provides better performance compared to the default SSL implementation within the JDK. For more information, including how to reduce the dependency size, refer to the performance tuning section of the wiki.

Next steps

Contributing

This project welcomes contributions and suggestions. Most contributions require you to agree to a Contributor License Agreement (CLA) declaring that you have the right to, and actually do, grant us the rights to use your contribution. For details, visit https://cla.microsoft.com.

When you submit a pull request, a CLA-bot will automatically determine whether you need to provide a CLA and decorate the PR appropriately (e.g., label, comment). Simply follow the instructions provided by the bot. You will only need to do this once across all repos using our CLA.

This project has adopted the Microsoft Open Source Code of Conduct. For more information see the Code of Conduct FAQ or contact [email protected] with any additional questions or comments.

Packages
Package
Description
com.azure.storage.blob.specialized.cryptography
Package containing the classes for performing client-side encryption of blob contents.