Name signers after nips

2024-08-08 11:43:29 -07:00
parent 536c8123f4
commit a8d0f5bc4f
9 changed files with 132 additions and 124 deletions
@@ -0,0 +1,85 @@
+import {UnwrappedEvent, SignedEvent, HashedEvent, EventTemplate, WRAP, SEAL} from '@welshman/util'
+import {own, hash, decrypt, ISigner} from './util'
+import {Nip01Signer} from './signers/nip01'
+
+export const seen = new Map<string, UnwrappedEvent | Error>()
+
+export const now = (drift = 0) =>
+  Math.round(Date.now() / 1000 - Math.random() * Math.pow(10, drift))
+
+export const getRumor = async (signer: ISigner, template: EventTemplate) =>
+  hash(own(await signer.getPubkey(), template))
+
+export const getSeal = async (signer: ISigner, pubkey: string, rumor: HashedEvent) =>
+  signer.sign(hash({
+    kind: SEAL,
+    pubkey: await signer.getPubkey(),
+    content: await signer.nip44.encrypt(pubkey, JSON.stringify(rumor)),
+    created_at: now(5),
+    tags: [],
+  }))
+
+export const getWrap = async (wrapper: ISigner, pubkey: string, seal: SignedEvent, tags: string[][]) =>
+  wrapper.sign(hash({
+    kind: WRAP,
+    pubkey: await wrapper.getPubkey(),
+    content: await wrapper.nip44.encrypt(pubkey, JSON.stringify(seal)),
+    created_at: now(5),
+    tags: [...tags, ["p", pubkey]],
+  }))
+
+export const wrap = async (signer: ISigner, wrapper: ISigner, pubkey: string, template: EventTemplate, tags: string[][] = []) => {
+  const rumor = await getRumor(signer, template)
+  const seal = await getSeal(signer, pubkey, rumor)
+  const wrap = await getWrap(wrapper, pubkey, seal, tags)
+
+  return Object.assign(rumor, {wrap}) as UnwrappedEvent
+}
+
+export const unwrap = async (signer: ISigner, wrap: SignedEvent) => {
+  // Avoid decrypting the same event multiple times
+  if (seen.has(wrap.id)) {
+    const rumorOrError = seen.get(wrap.id)
+
+    if (rumorOrError instanceof Error) {
+      throw rumorOrError
+    } else {
+      return rumorOrError
+    }
+  }
+
+  try {
+    const seal = JSON.parse(await decrypt(signer, wrap.pubkey, wrap.content))
+    const rumor = JSON.parse(await decrypt(signer, seal.pubkey, seal.content))
+
+    if (seal.pubkey !== rumor.pubkey) throw new Error("Seal pubkey does not match rumor pubkey")
+
+    seen.set(wrap.id, rumor)
+
+    return Object.assign(rumor, {wrap}) as UnwrappedEvent
+  } catch (error) {
+    seen.set(wrap.id, error as Error)
+
+    throw error
+  }
+}
+
+// This is a utility that makes it harder to re-use wrapper signers, since that can result in
+// leaked metadata. It simultaneously makes it easier to wrap stuff, because it allows for
+// wrapping a single user signer and omit the wrapper signer argument to wrap, while still
+// making it possible to pass a wrapper signer if desired.
+export class Nip59 {
+  constructor(private signer: ISigner, private wrapper?: ISigner) {}
+
+  static fromSigner = (signer: ISigner) => new Nip59(signer)
+
+  static fromSecret = (secret: string) => new Nip59(new Nip01Signer(secret))
+
+  withWrapper = (wrapper: ISigner) => new Nip59(this.signer, wrapper)
+
+  wrap = (pubkey: string, template: EventTemplate, tags: string[][] = []) =>
+    wrap(this.signer, this.wrapper || Nip01Signer.ephemeral(), pubkey, template, tags)
+
+  unwrap = (event: SignedEvent) =>
+    unwrap(this.signer, event)
+}