Directory scoped SAS provides constrained access to a single directory when using ADLS Gen2. This can be used to provide access to a directory and the files it contains.
Previously a SAS could be used to provide access to a filesystem or a file but not a directory. This added flexibility allows more granular and easier access privilege assignment.
To use directory scoped SAS previous Blob REST versions are supported but the authentication version must be 2020-02-10 or higher. ADLS Gen2 filesystem SDK’s also support directory scoped SAS and you can also generate a directory-scoped SAS via the Azure portal by selecting a directory and the action “Generate SAS”.
Read the SAS overview.
Learn how to use user delegation SAS with directory scope or a service SAS.