What is the best authentication method to access Azure Data Lake Store from Azure Synapse Analytics Workspace?

Managed identities provide a seamless way for Azure services to authenticate and authorize securely without the need for explicit credentials. When accessing Azure Data Lake Store from Azure Synapse Analytics Workspace, utilizing managed identities is beneficial for several reasons.

With managed identities, Azure Synapse can automatically obtain a token for Azure Data Lake Store, thereby eliminating the potential security risks associated with hard-coded credentials or keys. This method simplifies the management of authentication, as there is no need to rotate keys or secrets manually.

Moreover, managed identities integrate well with Azure's resource access policy features, allowing for fine-grained access control and easier auditing of who has access to what data. By using Azure Active Directory (AAD) roles, administrators can specify permissions at a granular level, ensuring that only the necessary services and users can access the data.

While storage account keys and shared access signatures provide ways to access resources, they involve handling sensitive information that could be exposed. OAuth tokens also offer secure access but typically require more configuration and management compared to the streamlined approach that managed identities offer within the Azure ecosystem.

Thus, using managed identities for authentication when accessing Azure Data Lake Store from Azure Synapse Analytics is the most secure and efficient method.