nips/39.md

NIP-39

External Identities in Profiles

draft optional

Abstract

Nostr protocol users may have other online identities such as usernames, profile pages, keypairs etc. they control and they may want to include this data in their profile metadata so clients can parse, validate and display this information.

i tag on a metadata event

A new optional i tag is introduced for kind 0 metadata event contents in addition to name, about, picture fields as included in NIP-01:

{
  "kind": 0,
  "tags": [
    ["i", "github:semisol", "9721ce4ee4fceb91c9711ca2a6c9a5ab"],
    ["i", "twitter:semisol_public", "1619358434134196225"],
    ["i", "mastodon:bitcoinhackers.org/@semisol", "109775066355589974"],
    ["i", "telegram:1087295469", "nostrdirectory/770"],
    ["i", "openpgp4fpr:1A04E0F1A78D982BD8885B7EB325A9C5F70849D0", "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", "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"]
  ],
  // ...
}

An i tag will have two parameters and an optional third parameter, which are defined as the following:

1. type:identity: This is the platform name (for example github) or the linked cryptographic identity type (for example openpgp4fpr), and the identity on that platform (for example semisol) or public key fingerprint (for example 1A04E0F1A78D982BD8885B7EB325A9C5F70849D0) joined together with :.
2. proof: String that points to the proof of owning this identity or is the proof itself (crytographic signature).
3. The full public key in the case of a cryptographic identity.

Clients SHOULD process any i tags with more than 3 values for future extensibility. Identity provider names SHOULD only include a-z, 0-9 and the characters ._-/ and MUST NOT include :. Identity names SHOULD be normalized if possible by replacing uppercase letters with lowercase letters, and if there are multiple aliases for an entity the primary one should be used.

Revocation

The event MAY be updated by removing i tags that no longer apply.

Claim types

github

Identity: A GitHub username.

Proof: A GitHub Gist ID. This Gist should be created by <identity> with a single file that has the text Verifying that I control the following Nostr public key: <npub encoded public key>. This can be located at https://gist.github.com/<identity>/<proof>.

twitter

Identity: A Twitter username.

Proof: A Tweet ID. The tweet should be posted by <identity> and have the text Verifying my account on nostr My Public Key: "<npub encoded public key>". This can be located at https://twitter.com/<identity>/status/<proof>.

mastodon

Identity: A Mastodon instance and username in the format <instance>/@<username>.

Proof: A Mastodon post ID. This post should be published by <username>@<instance> and have the text Verifying that I control the following Nostr public key: "<npub encoded public key>". This can be located at https://<identity>/<proof>.

telegram

Identity: A Telegram user ID.

Proof: A string in the format <ref>/<id> which points to a message published in the public channel or group with name <ref> and message ID <id>. This message should be sent by user ID <identity> and have the text Verifying that I control the following Nostr public key: "<npub encoded public key>". This can be located at https://t.me/<proof>.

openpgp4fpr

Identity: An OpenPGP fingerprint as described in the openpgp4fpr URI scheme, lowercased.

Proof: A binary signature of the text Verifying that I control the following Nostr public key: "<npub encoded public key>" converted to base64 format, unwrapped.

Public key material: The full, binary, non-ASCII, OpenPGP public key converted to base64 format, unwrapped.

Example

Using text Verifying that I control the following Nostr public key: "npub1wf4pufsucer5va8g9p0rj5dnhvfeh6d8w0g6eayaep5dhps6rsgs43dgh9"

{
  "kind": 0,
  "tags": [
    ["i", "openpgp4fpr:1a04e0f1a78d982bd8885b7eb325a9c5f70849d0", "owGbwMvMwCW2WXXl0e8cnhcYTzcmMaRNrekJSy3KTKvMzEtXKMlILFHwVEjOzyspys8BclMV0vJzcvLLQZJ++cUlRQoFpUk5mckK2amVVgpKeUCeYXmaSUFpWnFpcmqRaVmiRbplgUFRlmlKXkZZWmqGWYpFuUG6WWpiZWJqgWlKRkGxWVFxerGJcUp6hqUSV0cpC4MYF4OsmCKLFMuDj8t7Z2jf6IiugzmRlQnkPgYuTgGYyPY+hv9+FpdPrH+Zwn+hW5PfqcSoW2vFk08zM0xNtfXL7jRdmcLNyLB/Z3/a2cryx7NfyazK+Z/w2aWqcG+tiFz5lMtRUZuDlvEAAA==", "mDMEZgHdOxYJKwYBBAHaRw8BAQdA6pZgdsmDviRF45Cc+9MBb+udQDYgfGF6kBBUMByGxKa0F2ZyYW56YXAgPF9AZnJhbnphcC5jb20+iJMEExYKADsWIQQaBODxp42YK9iIW36zJanF9whJ0AUCZgHdOwIbAwULCQgHAgIiAgYVCgkICwIEFgIDAQIeBwIXgAAKCRCzJanF9whJ0L9GAQCuEPQtioDtiJicUHl8KDjSGfEMehAVv6lLbnd0SF3z/AD+PebBpY7bL/jF8BubiO+VogmHlkcFgxyWfD060000oAo="],
    // ...
  ],
  // ...
}

Example command to obtain a signature:

echo -n 'Verifying that I control the following Nostr public key: "<npub encoded public key>"' | gpg --sign | base64

Example command to export the public key:

gpg --export name@example.com | base64

x509

Identity: The X.509 certificate's SHA-256 fingerprint, lowercased.

Proof: A signature of the text Verifying that I control the following Nostr public key: "<npub encoded public key>" in base64 format, unwrapped.

Public key material: The full, binary, DER-formatted public key of the certificate converted to base64 format, unwrapped.

Example

Using text Verifying that I control the following Nostr public key: "npub1wf4pufsucer5va8g9p0rj5dnhvfeh6d8w0g6eayaep5dhps6rsgs43dgh9"

{
  "kind": 0,
  "tags": [
    ["i", "x509:99e33b0c2d07e75fcd9df7e40e886646ff667e3aa6648e1a1160b036cf2b9320", "MEQCIBPBFh0cXoYYv87ncjfTs+RrGKkJ2u6Q9WsmLUjxPJ5MAiBfjY3VY78DyVK1LeOrHKdfXXUWni273B46lcKiagKsOg==", "MFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAEH/reUjCQlypniNHFvJaW0eBAek57CEKhDOYBQp+f0GPOkooe0xLtHHmn/2cGoxvbXAjpvFkjJLXm2wcXMyB1fg=="],
    // ...
  ],
  // ...
}

Example command to find the SHA-256 fingerprint of the certificate from a keystore:

keytool -list -keystore example.keystore

Example of removing non-hexadecimal characters and lowercasing from the previous output:

echo -n "99:E3:3B:0C:2D:07:E7:5F:CD:9D:F7:E4:0E:88:66:46:FF:66:7E:3A:A6:64:8E:1A:11:60:B0:36:CF:2B:93:20" | tr -d -c '0-9A-Fa-f' | tr '[:upper:]' '[:lower:]'

Example commands to extract the private key and sign the message:

keytool -importkeystore -srckeystore example.keystore -destkeystore example.p12 -deststoretype pkcs12

openssl pkcs12 -in example.p12 -nocerts -noenc -out privatekey.pem

echo -n 'Verifying that I control the following Nostr public key: "<npub encoded public key>"' | openssl dgst -sha256 -binary -sign privatekey.pem | openssl base64 -A

Example command to extract the public key:

openssl rsa -in privatekey.pem -outform der -pubout | base64