[media-types] Re: [IANA #1459410] application/vnd.dai registration request

["Murray S. Kucherawy" <[e-mail]>]

Approved subject to a couple of tweaks suggested below.

-MSK

On Sat, Sep 12, 2026 at 5:25 PM David Dong via RT
<[e-mail]> wrote:
> Name: Christopher Whitlow
> Email: [e-mail]
>
> Media type name: application
> Media subtype name: vnd.dai
>
> Required parameters: N/A
> Optional parameters: N/A
>
> Encoding considerations: binary
>
> The file is a sectioned container: a header, a section table, page-aligned sections holding a JSON manifest, a zip archive of the application, and a SQLite database, and a 64-byte footer. The footer carries a generation counter and the SHA-256 of the database section.
>
> Security considerations:
>
> A DAI container carries executable content: an HTML application intended to run only inside a host that applies the isolation defined in §4 of the specification (an opaque-origin sandboxed frame under a Content Security Policy permitting no network connection). The specification requires that a host not applying that isolation does not execute the content.
>
> The container is a sectioned binary file holding a JSON manifest, a zip archive of the application, and a SQLite database. The manifest carries SHA-256 digests of every archive entry and may carry an ECDSA P-256 signature over them in a COSE_Sign1 envelope. The specification requires a host to verify every digest before running anything and to verify the signature when a key is present (§7). The signature covers the manifest and the application, not the database; the database section is verified separately against a SHA-256 digest held in the file's footer (§2). Verification establishes that the file is unchanged since it was signed, not the identity of the signer; §8 and §9.6 describe what a host may claim about a publisher.
>
> Because the archive is inflated before its manifest can be checked, the specification requires a reader to bound decompression in advance — a limit on the bytes produced for any one entry, on the total across entries, and on the number of entries — refusing rather than allocating when a declared size, the declared total, or the entry count exceeds that limit, and stopping if an entry inflates past the size it declares (§7). The manifest contains no active content.
>
> The application may read and write the SQLite database. The format grants it no capability to reach the network, the filesystem beyond the file itself, or other origins.
>
> Privacy: the file may contain personal data the application stored. It contains no tracking, and the specification requires that a host send nothing when opening a file.
>
> Interoperability considerations:
>
> The format is versioned by the manifestVersion field in the manifest. A reader accepts the versions it implements and refuses others, reporting a refusal that tells the person to update the host (§9.1). The specification defines versions 2 and 3. A conformance suite and an independent reference reader in Python are published with the specification.
>
> Published specification: DAI Container Format v0.2, §2 (the sectioned form), §7 (verification), and §9 (manifestVersion 3): https://github.com/dynamicapplicationinterface/dai-core/blob/main/docs/spec-v0.2.md
>
> Applications which use this media: The DAI opener (https://opendai.app) the DAI desktop application, and the dai command line tool; any host implementing the specification.
>
> Fragment identifier considerations: N/A
> Restrictions on usage: N/A
> Provisional registration? (standards tree only): No
>
> Additional information:
>
> Deprecated alias names for this type: N/A
> Magic number(s): the first four bytes are DAI (0x44 0x41 0x49 0x00)

This should be tightened up; I suggest:

Magic number(s): the first four bytes are "DAI" followed by a NULL
byte (0x44 0x41 0x49 0x00)

> File extension(s): '.dai'

I think the single quotes should be removed.

> Macintosh file type code: N/A
> Object Identifiers: N/A
>
> Other Information & Comments: N/A
>
> Person to contact for further information:
>
> Name: Christopher Whitlow
> Email: [e-mail]
>
> Intended usage: COMMON
>
> Author/Change controller: Christopher Whitlow / Dynamic Application Interface Opensource Project