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Propose Naam as naming system powered by IPNI
Define specification for Naming As Advertisement (Naam) protocol, which enables publication, update and resolution of IPNS records over IPNI advertisements.
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| # Naam: Naming As Advertisement | ||
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| **Author(s)**: | ||
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| - [Masih Derkani](https://github.com/masih) | ||
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| **Maintainer(s)**: | ||
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| - [Masih Derkani](https://github.com/masih) | ||
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| * * * | ||
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| **Abstract** | ||
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| This document defines the **N**aming **A**s **A**dvertise**m**ent (Naam) protocol: a mechanism by | ||
| which [IPNI](IPNI.md) can be used to both publish, and | ||
| resolve [IPNS](https://github.com/ipfs/specs/blob/main/ipns/IPNS.md) records. Naam utilises the | ||
| extensible IPNI [advertisement metadata](IPNI.md#metadata) to encode IPNS records and form an | ||
| advertisement. The resulting advertisements are consumable by indexer nodes, just like any other | ||
| advertisement. Further, to resolve IPNI records, Naam utilises the existing | ||
| IPNI [multihash lookup API](IPNI.md#get-multihashmultihash) to discover IPNI records. | ||
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| ## Table of Contents | ||
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| * [Introduction](#introduction) | ||
| * [Specification](#specification) | ||
| + [IPNS Record Publication](#ipns-record-publication) | ||
| + [Updating IPNS Records](#updating-ipns-records) | ||
| + [Removing IPNS Records](#removing-ipns-records) | ||
| + [Resolving IPNS Records](#resolving-ipns-records) | ||
| * [Limitations](#limitations) | ||
| + [IPNS Record Size](#ipns-record-size) | ||
| + [Record Validity Duration](#record-validity-duration) | ||
| * [Security](#security) | ||
| + [Advertisement Verifiability](#advertisement-verifiability) | ||
| + [Reputation](#reputation) | ||
| * [Privacy](#privacy) | ||
| * [Implementations](#implementations) | ||
| * [Related Resources](#related-resources) | ||
| * [Copyright](#copyright) | ||
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| ## Introduction | ||
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| IPNI introduces a set of protocols to discover providers for content-addressable data, along with | ||
| the protocols over which the data can be retrieved. Content providers maintain a chain of | ||
| advertisements that collectively capture the list of multihashes they provide. IPNI network is | ||
| actively being integrated across multiple networks, including IPFS and FileCoin. | ||
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| As the IPFS network grows, it is desirable to enable alternative content routing mechanisms in order | ||
| to provide the best user experience possible; e.g. fast time-to-first-byte, low latency lookups, | ||
| etc. IPNI already offers a DHT alternative to discover providers for a given CID. However, DHT in | ||
| IPFS provides other functionalities that go beyond provider lookup. One such functionality is IPNS: | ||
| InterPlanetary Naming System. | ||
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| IPNS compliments the immutability of IPFS by providing a way to create cryptographically | ||
| verifiable, mutable pointers to content-addressed data. It is part of the core IPFS functionality, | ||
| which offers an intuitive way to enable naming service, such as mapping domain names to changing | ||
| CIDs. For IPNI to become a complete content routing system and a viable alternative to the existing | ||
| IPFS DHT it needs to support IPNS. This is where **N**aming **A**s **A**dvertise**m**ent | ||
| (Naam) comes in. | ||
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| ## Specification | ||
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| Naam is a naming protocol that build on top of the existing IPNI protocol to facilitate a naming | ||
| system. It enables publication and resolution of IPNS records using the IPNI advertisements and | ||
| indexer node find APIs. Naam utilises the extensible advertisement metadata field to embed IPNS | ||
| records and produce advertisements that are consumable by existing indexer nodes without requiring | ||
| any change to the existing ingestion pipeline nor lookup API. | ||
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| This approach offers two key advantages; it: | ||
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| 1) reuses the existing IPNI network to implement a name service, which takes IPNI closer to offering | ||
| a fully featured DHT alternative for the IPFS network without having to run any additional | ||
| services dedicated to resolving IPNS records , and | ||
| 2) preserves an immutable historical catalogue of all IPNS records published by a peer, which can be | ||
| used for reputation analysis and ultimately holding peers responsible for their participation in | ||
| the network. | ||
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| Naam naming system involves three main components: | ||
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| 1) **Publisher** - which makes a chain of specifically crafted advertisements available for | ||
| ingestion by the network indexers, | ||
| 2) **Network Indexer** - which is an IPNI node responsible for ingesting advertisements and exposing | ||
| find APIs, and | ||
| 3) **Resolver** - which with the aid of network indexers given an IPNS key resolves its | ||
| corresponding record. | ||
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| The flow of information between the three components is similar to the indexing ecosystem depicted | ||
| in IPNI spec: publishers create and publish advertisements -> network indexers ingest them -> and | ||
| similar to retrieval clients resolvers use the find API to map a given IPNS key to IPNS record. In | ||
| this flow no changes are needed on network indexers. Therefore, the reminder of this document | ||
| focuses on interactions of Publishers, Resolvers and the data format exchanged between them. For | ||
| more information on how network indexers ingest advertisements and provide lookup APIs, please | ||
| see [IPNI](IPNI.md). | ||
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| ### IPNS Record Publication | ||
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| Naam publishes IPNS records via Publishers, which create IPNI-compliant advertisements that | ||
| embed IPNS records and are signed by their identity. The produced advertisements consist of: | ||
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| * **`PreviousID`** - the optional link to the previous Naam advertisement. `nil` indicates no | ||
| previous advertisements. | ||
| * **`Provider`** - the publisher peer ID. | ||
| * **`Addresses`** - the array of multiaddrs over which the publisher can be reached. | ||
| * **`Entries`** - the link to an `EntryChunk` IPLD node, as specified by IPNI, that contains a | ||
| single entry: the multihash of IPNS record key with `nil` as link to `Next`. | ||
| * **`ContextID`** - fixed to UTF-8 bytes encoding of the value `/ipni/naam`. | ||
| * **`Metadata`** - the bytes representation of Naam metadata, consisting of: | ||
| * the varint representation of IPNS multicodec code, i.e. `0xe5`, as bytes, | ||
| * followed by the marshalled IPNS record. | ||
| * **`IsRm`** - the boolean value specifying weather an IPNS entry is being added/updated, | ||
| i.e. `false`, or removed, i.e. `true`. | ||
| * **`Signature`** - the advertisement signature calculated as specified by IPNI specification. | ||
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| #### `Entries` | ||
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| `Entires` in a typical advertisement are responsible for capturing the list of multihashes | ||
| corresponding to the content hosted by a provider. Once ingested, the indexer nodes facilitate | ||
| lookup of providers over find APIs via the same multihashes. | ||
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| Naam repurposes the same advertisement structure by specifically crafting entries of advertisement | ||
| such that the indexer node find API can also be repurposed to lookup IPNS records. Naam forms a | ||
| single `EntryChunk` IPLD node, that contains a single multihash calculated as: | ||
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| * the SHA-256 of IPNS Record Key, i.e. `/ipns/<ipns-key>`. | ||
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| This approach allows the resolvers to deterministically calculate the multihash used for lookup when | ||
| interacting with the indexer node find APIs. | ||
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| #### Context ID | ||
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| The field `ContextID` in a regular advertisement is used as a way to uniquely identify the metadata | ||
| associated to a list of multihashes. Naam uses a fixed value, `/ipni/naam`, as context ID to assure | ||
| that the metadata associated to the published advertisement for the same IPNI key is singular and | ||
| uniquely identifiable. | ||
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| Using a fixed value as context ID also enables network indexers to quickly differentiate Naam | ||
| advertisements from a typical content advertisement. This opens up future opportunities for | ||
| optimisation when it comes to ingesting Naam advertisements. For example, indexers can pro-actively | ||
| process IPNS records and offer bespoke APIs that understand IPNS record expiry/validity. | ||
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| #### Metadata | ||
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| `Metadata` is typically used to convey the list of protocols over which the advertised content is | ||
| retrievable. Further, this field is designed to be extensible: a valid metadata should start with a | ||
| `varint` signifying _some_ protocol ID followed by arbitrary bytes. There are currently three well | ||
| known protocol IDs. The protocol ID itself need not to be known by the indexer nodes. In fact, | ||
| indexers treat metadata as a black box and carry on processing advertisements. Instead, it is meant | ||
| to be a signal to the consumers of `Metadata`, i.e. retrieval clients, as a hint on how to decode | ||
| the remaining bytes. | ||
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| Naam utilises this extensibility to directly encode IPNS records as metadata. The Naam advertisement | ||
| metadata consists of: | ||
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| * `ipns` multicodec code `0xe5` as protocol ID, | ||
| * followed by marshalled IPNS Record. | ||
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| The use of metadata to capture IPNS records enables Naam to also utilise the built-in IPNI mechanism | ||
| for updating metadata to update IPNS records. Because, context ID nor the multihash in Naam | ||
| advertisements ever change for the same IPNS key. For more information, | ||
| see [Updating IPNS Records](#updating-ipns-records). | ||
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| Note that the IPNS multicodec code `0xe5` is tagged as "namespace" in the CSV table, which could | ||
| signify an IPNS path, not record. There is currently no multicodec code for IPNS records themselves. | ||
| Alternatively, a new multicodec code can be introduced to the | ||
| [multicodec CSV file](https://github.com/multiformats/multicodec/blob/master/table.csv) to avoid | ||
| potential confusion between the two. The new code can then be used as the Protocol ID of Naam | ||
| Metadata. | ||
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| ### Updating IPNS Records | ||
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| IPNI offers a built-in mechanism to efficiently update the metadata associated to a list of | ||
| multihashes without having to republish the entries. Indexer nodes uniquely identify the metadata by | ||
| the advertisement `Provider`, and `ContextID`. | ||
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| Both of these values remain the same in Naam advertisements: the former is the same peer ID that | ||
| forms part of the IPNS key, i.e. `/ipns/<ipns-key>`, and the latter is fixed. As a result, to update | ||
| an IPNS record, all that's needed is to publish a new Naam advertisement that: | ||
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| * links to the previous advertisement in `PrevousID` link as specified by IPNI, | ||
| * uses the same `Provider` and `ContextID` values as before, | ||
| * sets `IsRm` to `false`, and | ||
| * has the updated IPNS record in Naam Metadata format. | ||
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| Note that there is no need to specify `Entries` when updating an existing record. It is inferred by | ||
| the network indexers since `Provider` and `ContextID` in Naam advertisements never change. | ||
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| ### Removing IPNS Records | ||
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| IPNS has EOL and TTL features built-in. This means explicit removal of records is not strictly | ||
| required. Instead, records eventually expire. Though not strictly necessary, Naam protocol can | ||
| utilise IPNI to explicitly remove records just like a traditional DNS nameserver. | ||
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| The process to remove an IPNS record published via Naam protocol is identical to removal | ||
| advertisement specified by IPNI. Similar to a regular advertisement, an IPNS record may be removed | ||
| by publishing an advertisement that: | ||
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| * links to the previous advertisement in `PrevousID` link as specified by IPNI, | ||
| * uses the same `Provider` and `ContextID` values as before, | ||
| * sets `IsRm` to `true`, and | ||
| * sets `Entries` link to `NoEntries` as specified by IPNI. | ||
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| Once ingested, indexer nodes will eventually remove the Naam advertisement metadata along with the | ||
| publisher information. | ||
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| ### Resolving IPNS Records | ||
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| IPNS record resolution involves finding the IPNS record associated to a given IPNS key, i.e. | ||
| `/ipns/<ipns-key>`. As eluded to earlier, Naam uses the find API already provided by the network | ||
| indexers to achieve this. To resolve an IPNS record, a resolver: | ||
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| * calculates the multihash of the given IPNS key as its SHA-256, | ||
| * looks up the provider info for that multihash via the IPNI find API, | ||
| * decodes the metadata from the provider info as IPNS record, | ||
| * validates the record, and | ||
| * if valid returns its value. | ||
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| ## Limitations | ||
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| ### IPNS Record Size | ||
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| The maximum size of IPNS records supported by Naam is 1 KiB, even though IPNS specification suggests | ||
| a maximum limit of 10 KiB. The 1 KiB limit currently imposed by network indexers on the maximum size | ||
| of advertisement metadata. | ||
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| Basic tests show that a 1KiB limit is sufficiently large for storing simple IPNS records pointing to | ||
| IPFS paths, specially for records that do not need the peer's public key to be embedded into IPNS | ||
| records. For example, a Ed25519 peer ID also captures the peer's public key. A marshalled IPNS | ||
| record with such key type and empty value constructed | ||
| using [`go-ipns`](https://github.com/ipfs/go-ipns) library comes to `257` bytes, which leaves | ||
| sufficient space for encoding fairly long IPFS paths as the record value. | ||
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| Because of the size limitation NAAM Records also limit storing large IDENTITY CIDs as record value. | ||
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| ### Record Validity Duration | ||
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| The indexers will maintain information from inactive providers for up to a week. This means IPNS | ||
| records published by Naam with EOL of beyond a week should be re-published to remain resolvable. | ||
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| ## Security | ||
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| ### Advertisement Verifiability | ||
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| Naam advertisements will benefit from all the verifiability features of regular advertisements. They | ||
| are signed by the IPNS record publisher and are verified for validity before being ingested by the | ||
| network indexers. | ||
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| ### Reputation | ||
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| Similar to the IPNI indexing protocol, the use of immutable advertisement chain by Naam provides a | ||
| verifiable and immutable catalog of IPNS records exposed by a network participant. Access to such | ||
| historical data enables verifiable analysis of participant behaviour, and offers an opportunity to | ||
| design and develop reputation systems, which ultimately can contribute to the health of the network. | ||
| As far as I know, this is something that is not currently offered by the existing implementations of | ||
| IPNS. | ||
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| Even though, the specification of such reputation system is beyond the scope of this document, it is | ||
| important to point out such potential. Because, as the size of IPFS network grows so will the need | ||
| for reputation systems that enable users to choose from ever increasing "choices" across the | ||
| network. | ||
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| ## Privacy | ||
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| To be revisited when double-hashing work is finalised. | ||
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| ## Implementations | ||
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| * [`ipni/go-naam`](https://github.com/ipni/go-naam) - Golang implementtion of IPNI Naam protocol. | ||
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| ## Related Resources | ||
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| * [IPNS: InterPlanetary Naming System](https://github.com/ipfs/specs/blob/main/ipns/IPNS.md) | ||
| * [IPNS PubSub Router](https://github.com/ipfs/specs/blob/main/ipns/IPNS_PUBSUB.md) | ||
| * [IPNI: InterPlanetary Network Indexer](https://IPNI.md) | ||
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| ## Copyright | ||
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| Copyright and related rights waived via [CC0](https://creativecommons.org/publicdomain/zero/1.0/). |