<![CDATA[I'm adding support for multiple public keys per actor in Smithereen for future-proofing purposes.]]>I'm adding support for multiple public keys per actor in Smithereen for future-proofing purposes. Are there any signature algorithms other than RSA currently in use on the fediverse? ECDSA maybe?

]]>https://fedi.wiki/topic/ceef7a27-4a48-4dc2-9774-f852676a3de1/i-m-adding-support-for-multiple-public-keys-per-actor-in-smithereen-for-future-proofing-purposes.RSS for NodeMon, 27 Jul 2026 08:34:37 GMTFri, 17 Jul 2026 16:50:36 GMT60<![CDATA[Reply to I'm adding support for multiple public keys per actor in Smithereen for future-proofing purposes. on Mon, 27 Jul 2026 01:56:13 GMT]]>@silverpill @mariusor at last, I did it

]]>https://fedi.wiki/post/https://mastodon.social/users/grishka/statuses/116989452210148936https://fedi.wiki/post/https://mastodon.social/users/grishka/statuses/116989452210148936Mon, 27 Jul 2026 01:56:13 GMT<![CDATA[Reply to I'm adding support for multiple public keys per actor in Smithereen for future-proofing purposes. on Mon, 27 Jul 2026 01:25:37 GMT]]>@silverpill @mariusor ughhhhhhhh. So that's what the "multibase" thing is.... There's ANOTHER spec (https://www.w3.org/TR/cid/#multibase-0) that says that the first character of the string specifies which encoding it uses because it can be different (but not for this FEP). Amazing format. Very convenient to debug.

After that change, it turns out that the RSA key is encoded as "the weird Misskey format" that Java can't parse natively, but I already have the code to handle that at least.

]]>https://fedi.wiki/post/https://mastodon.social/users/grishka/statuses/116989331891234650https://fedi.wiki/post/https://mastodon.social/users/grishka/statuses/116989331891234650Mon, 27 Jul 2026 01:25:37 GMT<![CDATA[Reply to I'm adding support for multiple public keys per actor in Smithereen for future-proofing purposes. on Mon, 27 Jul 2026 01:03:19 GMT]]>@silverpill @mariusor OpenSSL ain't having any of it either

]]>https://fedi.wiki/post/https://mastodon.social/users/grishka/statuses/116989244174793429https://fedi.wiki/post/https://mastodon.social/users/grishka/statuses/116989244174793429Mon, 27 Jul 2026 01:03:19 GMT<![CDATA[Reply to I'm adding support for multiple public keys per actor in Smithereen for future-proofing purposes. on Mon, 27 Jul 2026 00:50:39 GMT]]>@silverpill @mariusor what is even going on here. It's definitely not base58 decoding since I tried several different decoders and they all give the same result.

The first key is from the Multikey array, the second one is the regular publicKey after base64 decoding.

]]>https://fedi.wiki/post/https://mastodon.social/users/grishka/statuses/116989194362604554https://fedi.wiki/post/https://mastodon.social/users/grishka/statuses/116989194362604554Mon, 27 Jul 2026 00:50:39 GMT<![CDATA[Reply to I'm adding support for multiple public keys per actor in Smithereen for future-proofing purposes. on Mon, 27 Jul 2026 00:47:44 GMT]]>@silverpill @mariusor what is even going on here. It's definitely not base58 decoding since I tried several different decoders and they all gave the same result.

]]>https://fedi.wiki/post/https://mastodon.social/users/grishka/statuses/116989182872812025https://fedi.wiki/post/https://mastodon.social/users/grishka/statuses/116989182872812025Mon, 27 Jul 2026 00:47:44 GMT<![CDATA[Reply to I'm adding support for multiple public keys per actor in Smithereen for future-proofing purposes. on Mon, 27 Jul 2026 00:06:19 GMT]]>@silverpill @mariusor the example key from the FEP also uses 2 for that... The FEP itself says "Implementers can use cryptographic keys of any type for which a Multicodec prefix is registered.", I'm very confused. There's 0x1205 for RSA public keys and 0xed for ed25519 ones for example.

]]>https://fedi.wiki/post/https://mastodon.social/users/grishka/statuses/116989020048739700https://fedi.wiki/post/https://mastodon.social/users/grishka/statuses/116989020048739700Mon, 27 Jul 2026 00:06:19 GMT<![CDATA[Reply to I'm adding support for multiple public keys per actor in Smithereen for future-proofing purposes. on Mon, 27 Jul 2026 00:00:46 GMT]]>@silverpill @mariusor so the prefix is always 2, which corresponds to "identity", which is quite useless, it could as well not be there

]]>https://fedi.wiki/post/https://mastodon.social/users/grishka/statuses/116988998195162440https://fedi.wiki/post/https://mastodon.social/users/grishka/statuses/116988998195162440Mon, 27 Jul 2026 00:00:46 GMT<![CDATA[Reply to I'm adding support for multiple public keys per actor in Smithereen for future-proofing purposes. on Sun, 26 Jul 2026 22:41:41 GMT]]>@silverpill @mariusor huh, interesting, I tried fetching your actor and it turns out one of the contexts uses a JSON-LD version that's too new for my JLD processor... Also probably the first time ever I'm seeing @ graph used in the wild.

Not really a problem for me as I was going to put these two contexts into my resources anyway and I could as well edit them.

]]>https://fedi.wiki/post/https://mastodon.social/users/grishka/statuses/116988687255936253https://fedi.wiki/post/https://mastodon.social/users/grishka/statuses/116988687255936253Sun, 26 Jul 2026 22:41:41 GMT<![CDATA[Reply to I'm adding support for multiple public keys per actor in Smithereen for future-proofing purposes. on Mon, 20 Jul 2026 20:07:51 GMT]]>@silverpill @mariusor well, because it's not part of the Java standard library so I'll have to implement it myself

]]>https://fedi.wiki/post/https://mastodon.social/users/grishka/statuses/116954108502057788https://fedi.wiki/post/https://mastodon.social/users/grishka/statuses/116954108502057788Mon, 20 Jul 2026 20:07:51 GMT<![CDATA[Reply to I'm adding support for multiple public keys per actor in Smithereen for future-proofing purposes. on Mon, 20 Jul 2026 20:06:49 GMT]]>@grishka @mariusor

Why would anyone suffer from base-58-btc? IMO it's nice.

base-58-btc is used in eddsa-jcs-2022 cryptosuite, in did:key and in other places. I don't know why, but it makes sense to use the same encoding everywhere.

IIRC newer specs from Verifiable Credentials group allow both base-58-btc and base-64-url.

]]>https://fedi.wiki/post/https://mitra.social/objects/019f8123-6b65-7de3-8372-2032938cf1c6https://fedi.wiki/post/https://mitra.social/objects/019f8123-6b65-7de3-8372-2032938cf1c6Mon, 20 Jul 2026 20:06:49 GMT<![CDATA[Reply to I'm adding support for multiple public keys per actor in Smithereen for future-proofing purposes. on Mon, 20 Jul 2026 19:35:38 GMT]]>@silverpill @mariusor ok, so after actually reading the FEP, I see that the encoded representation of each key has a variable-length integer prefix specifying which kind of key it is. And it's also encoded into "base-58-btc" so that... implementers suffer? I don't get it. Why not just use base64, that seems like an unnecessary nuisance

]]>https://fedi.wiki/post/https://mastodon.social/users/grishka/statuses/116953981826478493https://fedi.wiki/post/https://mastodon.social/users/grishka/statuses/116953981826478493Mon, 20 Jul 2026 19:35:38 GMT<![CDATA[Reply to I'm adding support for multiple public keys per actor in Smithereen for future-proofing purposes. on Fri, 17 Jul 2026 18:39:22 GMT]]>@silverpill nevermind, I found it in the FEP.

@grishka

]]>https://fedi.wiki/post/https://metalhead.club/users/mariusor/statuses/116936773619656990https://fedi.wiki/post/https://metalhead.club/users/mariusor/statuses/116936773619656990Fri, 17 Jul 2026 18:39:22 GMT<![CDATA[Reply to I'm adding support for multiple public keys per actor in Smithereen for future-proofing purposes. on Fri, 17 Jul 2026 18:37:42 GMT]]>@silverpill I see... Got a link to that, I should update my stuff...

@grishka

]]>https://fedi.wiki/post/https://metalhead.club/users/mariusor/statuses/116936767067755155https://fedi.wiki/post/https://metalhead.club/users/mariusor/statuses/116936767067755155Fri, 17 Jul 2026 18:37:42 GMT<![CDATA[Reply to I'm adding support for multiple public keys per actor in Smithereen for future-proofing purposes. on Fri, 17 Jul 2026 18:34:40 GMT]]>@mariusor @grishka For example, assertionMethod specifies keys for signing, keyAgreement for encryption https://www.w3.org/TR/cid/#verification-relationships

]]>https://fedi.wiki/post/https://mitra.social/objects/019f715b-f800-7652-8992-14013b90f0dchttps://fedi.wiki/post/https://mitra.social/objects/019f715b-f800-7652-8992-14013b90f0dcFri, 17 Jul 2026 18:34:40 GMT<![CDATA[Reply to I'm adding support for multiple public keys per actor in Smithereen for future-proofing purposes. on Fri, 17 Jul 2026 18:32:22 GMT]]>@mariusor @grishka Lol, true. But this is not the only reason for writing FEP-521a.

publicKey was marked as deprecated upstream and now more fine-grained properties are recommended

]]>https://fedi.wiki/post/https://mitra.social/objects/019f7159-dcb6-7a21-b080-e62516838e2ehttps://fedi.wiki/post/https://mitra.social/objects/019f7159-dcb6-7a21-b080-e62516838e2eFri, 17 Jul 2026 18:32:22 GMT<![CDATA[Reply to I'm adding support for multiple public keys per actor in Smithereen for future-proofing purposes. on Fri, 17 Jul 2026 18:22:43 GMT]]>@grishka it should be. The ASN package that gets encoded to PEM should have the algorithm value set:

curl -s https://federated.id/actors/a1517c06-7131-4437-84b0-025837e9da39 | jq -r .publicKey.publicKeyPem | openssl asn1parse

]]>https://fedi.wiki/post/https://metalhead.club/users/mariusor/statuses/116936708144894872https://fedi.wiki/post/https://metalhead.club/users/mariusor/statuses/116936708144894872Fri, 17 Jul 2026 18:22:43 GMT<![CDATA[Reply to I'm adding support for multiple public keys per actor in Smithereen for future-proofing purposes. on Fri, 17 Jul 2026 18:22:07 GMT]]>@mariusor @silverpill Smithereen is one of the few ActivityPub implementations that actually uses JSON-LD contexts not just for LD signatures but also when parsing data, so not a problem for me in particular

]]>https://fedi.wiki/post/https://mastodon.social/users/grishka/statuses/116936705825889598https://fedi.wiki/post/https://mastodon.social/users/grishka/statuses/116936705825889598Fri, 17 Jul 2026 18:22:07 GMT<![CDATA[Reply to I'm adding support for multiple public keys per actor in Smithereen for future-proofing purposes. on Fri, 17 Jul 2026 18:20:43 GMT]]>@silverpill yep. Your bane, more JSON-LD bullshit. 😄

@grishka

]]>https://fedi.wiki/post/https://metalhead.club/users/mariusor/statuses/116936700277285357https://fedi.wiki/post/https://metalhead.club/users/mariusor/statuses/116936700277285357Fri, 17 Jul 2026 18:20:43 GMT<![CDATA[Reply to I'm adding support for multiple public keys per actor in Smithereen for future-proofing purposes. on Fri, 17 Jul 2026 18:19:08 GMT]]>@mariusor @grishka This time it's the other way around. I wrote the FEP, and 3 years later they implemented it.

The alternative is publicKey array I guess?

]]>https://fedi.wiki/post/https://mitra.social/objects/019f714d-bf18-7e51-81c8-871199dc54f5https://fedi.wiki/post/https://mitra.social/objects/019f714d-bf18-7e51-81c8-871199dc54f5Fri, 17 Jul 2026 18:19:08 GMT<![CDATA[Reply to I'm adding support for multiple public keys per actor in Smithereen for future-proofing purposes. on Fri, 17 Jul 2026 18:17:14 GMT]]>@mariusor Java's built-in crypto API can't do that unfortunately as far as I know. I guess I'll have to try every supported type on every key until I find one that works

]]>https://fedi.wiki/post/https://mastodon.social/users/grishka/statuses/116936686618178853https://fedi.wiki/post/https://mastodon.social/users/grishka/statuses/116936686618178853Fri, 17 Jul 2026 18:17:14 GMT<![CDATA[Reply to I'm adding support for multiple public keys per actor in Smithereen for future-proofing purposes. on Fri, 17 Jul 2026 18:15:52 GMT]]>@silverpill are we allowing Mastodon guide ActivityPub development again, when alternatives exist?

@grishka

]]>https://fedi.wiki/post/https://metalhead.club/users/mariusor/statuses/116936681215443428https://fedi.wiki/post/https://metalhead.club/users/mariusor/statuses/116936681215443428Fri, 17 Jul 2026 18:15:52 GMT<![CDATA[Reply to I'm adding support for multiple public keys per actor in Smithereen for future-proofing purposes. on Fri, 17 Jul 2026 18:15:03 GMT]]>@grishka yeah, you need to let the crypto library autodetect the type of key. OpenSSL manages to do it:

curl -s https://federated.id/actors/a1517c06-7131-4437-84b0-025837e9da39 | jq -r .publicKey.publicKeyPem | openssl pkey -pubin -text

]]>https://fedi.wiki/post/https://metalhead.club/users/mariusor/statuses/116936677985564767https://fedi.wiki/post/https://metalhead.club/users/mariusor/statuses/116936677985564767Fri, 17 Jul 2026 18:15:03 GMT<![CDATA[Reply to I'm adding support for multiple public keys per actor in Smithereen for future-proofing purposes. on Fri, 17 Jul 2026 17:44:38 GMT]]>@silverpill @mariusor ohh so that's how backwards compatibility is going to work. I thought `publicKey` would just become an array since the spec permits that iirc

]]>https://fedi.wiki/post/https://mastodon.social/users/grishka/statuses/116936558436003402https://fedi.wiki/post/https://mastodon.social/users/grishka/statuses/116936558436003402Fri, 17 Jul 2026 17:44:38 GMT<![CDATA[Reply to I'm adding support for multiple public keys per actor in Smithereen for future-proofing purposes. on Fri, 17 Jul 2026 17:38:45 GMT]]>@grishka @mariusor My actor has an ed25519 key. Check out FEP-521a - that's what Mastodon is implementing.

]]>https://fedi.wiki/post/https://mitra.social/objects/019f7128-c773-77e2-b336-0c988d11d0f2https://fedi.wiki/post/https://mitra.social/objects/019f7128-c773-77e2-b336-0c988d11d0f2Fri, 17 Jul 2026 17:38:45 GMT