NIP-59

Gift Wrap

draft optional author:kieran

This NIP defines a simple method to protect event metadata leakage by using randomly generated keys.

A gift wrap event is a kind 1059 event which wraps another event with a single use key.

This event kind can be used to wrap DM's or other events which are considered private.

This is similar in concept to Onion Routing.

To wrap an event, sign it as usual then serialize it to JSON. This string should then be encrypted using NIP-44 with a different private key.

Next, add the signed payload to the content field of a new kind 1059 event, signed with the same key used to encrypt the content.

The key used to sign the wrapper and encrypt its contents can be created using any appropriate strategy:

• For the strongest security guarantees, it SHOULD be randomly generated.
• The sender MAY use sender private * event id mod curve.n instead of a completely random key. If this is done, the sender can "retain access" to the sent message and is capable of decrypting, deleting or otherwise operating on the outer message.

A p tag for the recipient MUST be added to the tags field on the outer event. To protect recipient identity, this may be a regular pubkey, or one representing a group of people sharing a private key for decryption.

The sender MAY copy tags from the inner event to the outer event. This weakens privacy guarantees, but may be useful to accommodate server-side filtering. A k tag MAY be added to the outer event to denote the kind of the inner event.

Example wrapped event:

{
    "id": "0bb58c5e646ff1a310d888347cd392f0490d80d9ce963a43d10f0af0b3a92d58",
    "pubkey": "67813274a3e44cc5f939cc29f1faa4e6b38f1ee4a22469262d6d9d19c377f027",
    "content": "{\"ciphertext\":\"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\",\"nonce\":\"CvLX+kBOEBM5ZRm/I+4fncvGqbrcb6Dy\",\"v\":1}",
    "kind": 1059,
    "created_at": 1686840217,
    "tags": [
        [
            "p",
            "63fe6318dc58583cfe16810f86dd09e18bfd76aabc24a0081ce2856f330504ed"
        ]
    ],
    "sig": "cdcc561865cc4f028311159a9417b717d93a681f957621052335bb3c581f85490cb3f596d251e92f7174d34eeb406ff009acde37588322fcb75c380e335a1b73"
}

The content is NIP-44 encrypted JSON string with the temporary key, this is the inner event:

{
    "id": "a3b3d167f560e9d15434534ee7bf51cf272b15e40e3e9a64501fb83fd0f06326",
    "pubkey": "63fe6318dc58583cfe16810f86dd09e18bfd76aabc24a0081ce2856f330504ed",
    "content": "example",
    "kind": 1,
    "created_at": 1686840217,
    "tags": [
        [
            "p",
            "63fe6318dc58583cfe16810f86dd09e18bfd76aabc24a0081ce2856f330504ed"
        ]
    ],
    "sig": "675a8cd35925928d6623ba18aea0eeb9691c462c59cac4a6441f9495eaec7182107ece7b7012bb628e28029f059362fcbce9bce3a00c05817480603d8f8112f5"
}

Clients can decrypt the gift wrapped event and can continue to work as normal.