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General Internet Engineering Task Force Web3 Wallet DNS Mapping This document proposes a standard for mapping wallets to domain names using TXT records. The goal is to provide a secure and scalable way to associate wallets with domain names, enabling seamless lookup as well as assisting in authentication. The proposal heavily uses DNSSEC to ensure security. We also will propose a mechanism for mapping a wallet back to a domain name.

Introduction There is fragmentation in the mapping of Web3 Wallets to Domain Names as well as the reverse lookup process. This document is putting forth a standard to map Web3 Wallet addresses to Domain Names and investigates the associated security and technical concerns. As the use of digital wallets and online services grows, the need for a standardized way to lookup wallet addresses in an human readable format becomes increasingly important. This proposal aims to provide a solution that is easy to implement, scalable, and secure. The proposed solution involves creating a TXT record with the record extension "_w3addr" to map a wallet to a domain name. The TXT record will contain a object that maps the wallet address to the registered coin type token . It is assumed that the record will be part of a DNSSEC signed zonefile and that users of this service will verify the signatures to ensure that the record has been returned without alteration in flight. On the reverse mapping, we propose that we allow a singular coin type/address be mapped to a domain name in DNS. This will also be protected by DNSSEC. We encourage users to use a more centralized registry for this.

Requirements Language The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 when, and only when, they appear in all capitals, as shown here.

Domain to Wallet Mapping

Record Format The TXT record SHALL have the following format:

_w3addr

is the TXT record name

IN

is the class of the record

TXT

is the type of the record

coin1:address1,coin2:address2,...

is the value of the record, containing a comma-separated list of coin:address pairs

Grammar for the record in EBNF format

record_list

represents the entire list of coin-address pairs

item

represents a coin-address pair

wildcard

is the symbol representing the default match

coin_name

represents the Symbol of a chain represented in

address

represents the public wallet address associated with a coin (e.g., "0xabcdefg", "0x12345", etc.)

The * symbol indicates zero or more occurrences of the preceding element. The + symbol indicates one or more occurrences. This grammar can be used to parse the input string and extract the chain identifier and addresses.

Example Suppose a user wants to map their wallet with the public key 0x1234567890abcdef to the domain example.com using the registered coin type tokens BTC and ETH. The TXT record would be:

Wildcard Support To support multiple wallets and chains, the TXT record SHALL allow for a solitary wildcard * to substitute for the default chain name. For example: The lookup will return the most specific record for a chain.

Multiple Records To support multiple records, the TXT record SHALL allow for multiple coin:address pairs separated by commas. If the record exceeds the 2048 character limit, it MAY be continued on additional TXT records. There is no guarantees on ordering the records so overlapping records MAY ordered at the resolver's discretion. In the event of duplicate chains it is RECOMMENDED that multiple records be returned dedupped for identical addresses.

Implementation Implementations of this RFC SHALL:

1. Support the creation and retrieval of TXT records with the _w3addr name for any given level of the DNS system.
2. Order the lookup of the wallet address based on the returned records.
3. Provide the wallet's public key for addressing by chain.

Wallet to Domain Reverse Mapping

Solution A wallet owner has the OPTIONAL ability to setup a reverse lookup using DNS in a similar manner for IANA in-addr.arpa and ip6.arpa against a centralized service. Queriants will be able to query a CNAME record with wallet information, to get a domain mapping, they have the OPTIONAL ability to query with a chain designation using the registered coin type defined in SLIP-0044. Until IANA decides to provide this service, this MAY be offered by outside parties.

Limitations DNS is case insensitive, but some wallet addresses are case sensitive. Because of the vast namespace available in Web3 Addresses, it is unlikely, but MAY result in a collision.

Reverse Wallet Mapping Example There is currently no IANA support lookup path, but a user will be able to lookup from a reverse mapping provider until there is a centralized body. It can be qualified as a chain designation or Default

Multiple mappings It is NOT SUPPORTED for a wallet / network pair to point to multiple domains. The CNAME record does not support returning multiple records.

Potential Implementation

1. A service will take a signed message telling the reverse lookup service for the wallet to point to a domain. OPTIONAL with chain information.
2. The service SHALL validate the signed message.
3. The service SHALL validate the domain to wallet mapping using the above Domain to Wallet Protocol.
4. The service SHALL update the DNS record acting as a registry for Wallet to Domain mapping.
5. OPTIONAL the service should validate the Domain to Wallet mapping on a periodic basis.

Security Considerations To ensure the security of the mapping, the following measures will be taken:

1. The TXT record SHALL BE stored in a secure location, such as a DNSSEC-signed zone.
2. The implementation SHALL validate the DNSSEC record.
3. The wallet record SHALL be protected from replay attacks via DNSSEC time invalidation.

If the source of the DNS zone is compromised, the wallet address mapping is compromised, it is imperative that this not occur.

IANA Considerations This proposal requests that IANA support reverse mapping of wallet addresses to domains.

References Normative References Informational References

Appendix 1: Example code Here is an example of how to create and retrieve a TXT records using the _w3addr name:

Contributors Thanks to all of the contributors for contributions to security and clarity.

yevhenii@d3.email

kai@d3.email

Acknowledgements Reviewed by:

jothan@frakes.com