diff --git a/src/controllers/api/pleroma.ts b/src/controllers/api/pleroma.ts
index a500161..40e0c2b 100644
--- a/src/controllers/api/pleroma.ts
+++ b/src/controllers/api/pleroma.ts
@@ -1,8 +1,8 @@
 import { type AppController } from '@/app.ts';
 import { Conf } from '@/config.ts';
-import { decryptAdmin, encryptAdmin } from '@/crypto.ts';
 import { z } from '@/deps.ts';
 import { configSchema, elixirTupleSchema } from '@/schemas/pleroma-api.ts';
+import { AdminSigner } from '@/signers/AdminSigner.ts';
 import { eventsDB } from '@/storages.ts';
 import { createAdminEvent } from '@/utils/api.ts';
 import { jsonSchema } from '@/schema.ts';
@@ -18,7 +18,7 @@ const frontendConfigController: AppController = async (c) => {
   }], { signal });
 
   const configs = jsonSchema.pipe(z.array(configSchema)).catch([]).parse(
-    event?.content ? await decryptAdmin(Conf.pubkey, event.content) : '',
+    event?.content ? await new AdminSigner().nip04.decrypt(Conf.pubkey, event.content) : '',
   );
 
   const frontendConfig = configs.find(({ group, key }) => group === ':pleroma' && key === ':frontend_configurations');
@@ -47,7 +47,7 @@ const configController: AppController = async (c) => {
   }], { signal });
 
   const configs = jsonSchema.pipe(z.array(configSchema)).catch([]).parse(
-    event?.content ? await decryptAdmin(pubkey, event.content) : '',
+    event?.content ? await new AdminSigner().nip04.decrypt(pubkey, event.content) : '',
   );
 
   return c.json({ configs, need_reboot: false });
@@ -66,7 +66,7 @@ const updateConfigController: AppController = async (c) => {
   }], { signal });
 
   const configs = jsonSchema.pipe(z.array(configSchema)).catch([]).parse(
-    event?.content ? await decryptAdmin(pubkey, event.content) : '',
+    event?.content ? await await new AdminSigner().nip04.decrypt(pubkey, event.content) : '',
   );
 
   const { configs: newConfigs } = z.object({ configs: z.array(configSchema) }).parse(await c.req.json());
@@ -82,7 +82,7 @@ const updateConfigController: AppController = async (c) => {
 
   await createAdminEvent({
     kind: 30078,
-    content: await encryptAdmin(pubkey, JSON.stringify(configs)),
+    content: await await new AdminSigner().nip04.encrypt(pubkey, JSON.stringify(configs)),
     tags: [['d', 'pub.ditto.pleroma.config']],
   }, c);
 
diff --git a/src/crypto.ts b/src/crypto.ts
deleted file mode 100644
index 9cafb51..0000000
--- a/src/crypto.ts
+++ /dev/null
@@ -1,14 +0,0 @@
-import { Conf } from '@/config.ts';
-import { nip04 } from '@/deps.ts';
-
-/** Encrypt a message as the Ditto server account. */
-function encryptAdmin(targetPubkey: string, message: string): Promise<string> {
-  return nip04.encrypt(Conf.seckey, targetPubkey, message);
-}
-
-/** Decrypt a message as the Ditto server account. */
-function decryptAdmin(targetPubkey: string, message: string): Promise<string> {
-  return nip04.decrypt(Conf.seckey, targetPubkey, message);
-}
-
-export { decryptAdmin, encryptAdmin };
diff --git a/src/deps.ts b/src/deps.ts
index 201c16a..3e0cf0a 100644
--- a/src/deps.ts
+++ b/src/deps.ts
@@ -17,7 +17,6 @@ export {
   getPublicKey,
   matchFilter,
   matchFilters,
-  nip04,
   nip05,
   nip13,
   nip19,
diff --git a/src/pipeline.ts b/src/pipeline.ts
index caa58fb..ead0044 100644
--- a/src/pipeline.ts
+++ b/src/pipeline.ts
@@ -1,5 +1,4 @@
 import { Conf } from '@/config.ts';
-import { encryptAdmin } from '@/crypto.ts';
 import { addRelays } from '@/db/relays.ts';
 import { deleteAttachedMedia } from '@/db/unattached-media.ts';
 import { Debug, LNURL, type NostrEvent } from '@/deps.ts';
@@ -198,7 +197,7 @@ async function payZap(event: DittoEvent, signal: AbortSignal) {
 
     const nwcRequestEvent = await signer.signEvent({
       kind: 23194,
-      content: await encryptAdmin(
+      content: await signer.nip04.encrypt(
         event.pubkey,
         JSON.stringify({ method: 'pay_invoice', params: { invoice: pr } }),
       ),
diff --git a/src/signers/APISigner.ts b/src/signers/APISigner.ts
index 3e20370..cc4cde3 100644
--- a/src/signers/APISigner.ts
+++ b/src/signers/APISigner.ts
@@ -1,9 +1,9 @@
 import { type AppContext } from '@/app.ts';
 import { Conf } from '@/config.ts';
-import { decryptAdmin, encryptAdmin } from '@/crypto.ts';
 import { HTTPException, type NostrEvent, type NostrSigner, NSecSigner, Stickynotes } from '@/deps.ts';
 import { connectResponseSchema } from '@/schemas/nostr.ts';
 import { jsonSchema } from '@/schema.ts';
+import { AdminSigner } from '@/signers/AdminSigner.ts';
 import { Sub } from '@/subs.ts';
 import { eventMatchesTemplate } from '@/utils.ts';
 import { createAdminEvent } from '@/utils/api.ts';
@@ -63,7 +63,7 @@ export class APISigner implements NostrSigner {
 
     createAdminEvent({
       kind: 24133,
-      content: await encryptAdmin(
+      content: await new AdminSigner().nip04.encrypt(
         pubkey,
         JSON.stringify({
           id: messageId,
@@ -93,7 +93,7 @@ export class APISigner implements NostrSigner {
     this.#c.req.raw.signal.addEventListener('abort', close);
 
     for await (const event of sub) {
-      const decrypted = await decryptAdmin(event.pubkey, event.content);
+      const decrypted = await new AdminSigner().nip04.decrypt(event.pubkey, event.content);
 
       const result = jsonSchema
         .pipe(connectResponseSchema)