diff --git a/js/nostrEventSchemas.js b/js/nostrEventSchemas.js
index 8f7e5372..c64ddd4b 100644
--- a/js/nostrEventSchemas.js
+++ b/js/nostrEventSchemas.js
@@ -302,22 +302,24 @@ const BASE_SCHEMAS = {
     },
     appendTags: DEFAULT_APPEND_TAGS,
     content: {
-      format: "nip04-json",
-      description: "Encrypted JSON: { subPubkeys: string[] }.",
+      format: "encrypted-tag-list",
+      description:
+        "NIP-04/NIP-44 encrypted JSON array of NIP-51 tag tuples (e.g., [['p', <hex>], …]).",
     },
   },
   [NOTE_TYPES.USER_BLOCK_LIST]: {
     type: NOTE_TYPES.USER_BLOCK_LIST,
     label: "User block list",
-    kind: 30002,
+    kind: 10000,
     identifierTag: {
       name: "d",
       value: BLOCK_LIST_IDENTIFIER,
     },
     appendTags: DEFAULT_APPEND_TAGS,
     content: {
-      format: "nip04-json",
-      description: "Encrypted JSON: { blockedPubkeys: string[] }.",
+      format: "encrypted-tag-list",
+      description:
+        "NIP-04/NIP-44 encrypted JSON array of mute tags per NIP-51 (e.g., [['p', <hex>], …]).",
     },
   },
   [NOTE_TYPES.HASHTAG_PREFERENCES]: {
@@ -1390,8 +1392,10 @@ export function buildSubscriptionListEvent({
   if (identifierName && identifierValue) {
     tags.push([identifierName, identifierValue]);
   }
-  if (typeof encryption === "string" && encryption) {
-    tags.push(["encrypted", encryption]);
+  const normalizedEncryption =
+    typeof encryption === "string" ? encryption.trim() : "";
+  if (normalizedEncryption) {
+    tags.push(["encrypted", normalizedEncryption]);
   }
   appendSchemaTags(tags, schema);
   return {
@@ -1416,12 +1420,14 @@ export function buildBlockListEvent({
   if (identifierName && identifierValue) {
     tags.push([identifierName, identifierValue]);
   }
-  if (typeof encryption === "string" && encryption) {
-    tags.push(["encrypted", encryption]);
+  const normalizedEncryption =
+    typeof encryption === "string" ? encryption.trim() : "";
+  if (normalizedEncryption) {
+    tags.push(["encrypted", normalizedEncryption]);
   }
   appendSchemaTags(tags, schema);
   return {
-    kind: schema?.kind ?? 30002,
+    kind: schema?.kind ?? 10000,
     pubkey,
     created_at,
     tags,
diff --git a/js/subscriptions.js b/js/subscriptions.js
index 1352c4a0..24263dc0 100644
--- a/js/subscriptions.js
+++ b/js/subscriptions.js
@@ -126,6 +126,82 @@ function determineDecryptionOrder(event, availableSchemes) {
   return prioritized.length ? prioritized : available;
 }
 
+function serializeSubscriptionTagMatrix(values) {
+  const tags = [];
+  const seen = new Set();
+  if (!values) {
+    return JSON.stringify(tags);
+  }
+  const iterable = Array.isArray(values)
+    ? values
+    : values instanceof Set
+    ? Array.from(values)
+    : [];
+  for (const candidate of iterable) {
+    const normalized = normalizeHexPubkey(candidate);
+    if (!normalized || seen.has(normalized)) {
+      continue;
+    }
+    seen.add(normalized);
+    tags.push(["p", normalized]);
+  }
+  return JSON.stringify(tags);
+}
+
+function parseSubscriptionPlaintext(plaintext) {
+  if (typeof plaintext !== "string" || !plaintext) {
+    return [];
+  }
+
+  let parsed;
+  try {
+    parsed = JSON.parse(plaintext);
+  } catch (error) {
+    devLogger.warn(
+      "[SubscriptionsManager] Failed to parse subscription ciphertext as JSON; treating as empty.",
+      error,
+    );
+    return [];
+  }
+
+  if (Array.isArray(parsed)) {
+    const collected = [];
+    const seen = new Set();
+    for (const entry of parsed) {
+      if (!Array.isArray(entry) || entry.length < 2) {
+        continue;
+      }
+      const marker = typeof entry[0] === "string" ? entry[0].trim().toLowerCase() : "";
+      if (marker !== "p") {
+        continue;
+      }
+      const normalized = normalizeHexPubkey(entry[1]);
+      if (!normalized || seen.has(normalized)) {
+        continue;
+      }
+      seen.add(normalized);
+      collected.push(normalized);
+    }
+    return collected;
+  }
+
+  if (parsed && typeof parsed === "object") {
+    const tagArray = Array.isArray(parsed.tags) ? parsed.tags : [];
+    if (tagArray.length) {
+      try {
+        return parseSubscriptionPlaintext(JSON.stringify(tagArray));
+      } catch {
+        // fall through to legacy handling
+      }
+    }
+
+    const legacy = Array.isArray(parsed.subPubkeys) ? parsed.subPubkeys : [];
+    return legacy.map((value) => normalizeHexPubkey(value)).filter(Boolean);
+  }
+
+  return [];
+}
+
 const getApp = () => getApplication();
 
 const listVideoViewEventsApi = (pointer, options) =>
@@ -135,7 +211,7 @@ const subscribeVideoViewEventsApi = (pointer, options) =>
 
 /**
  * Manages the user's subscription list (kind=30002) *privately*,
- * using NIP-04 encryption for the content field.
+ * using encrypted NIP-51 tag arrays (NIP-04/NIP-44) for the content field.
  * Also handles fetching and rendering subscribed channels' videos
  * in the same card style as your home page.
  */
@@ -295,13 +371,7 @@ class SubscriptionsManager {
 
       const decryptedStr = decryptResult.plaintext;
 
-      const parsed = JSON.parse(decryptedStr);
-      const subArray = Array.isArray(parsed.subPubkeys)
-        ? parsed.subPubkeys
-        : [];
-      const normalized = subArray
-        .map((value) => normalizeHexPubkey(value))
-        .filter((value) => Boolean(value));
+      const normalized = parseSubscriptionPlaintext(decryptedStr);
       this.subscribedPubkeys = new Set(normalized);
 
       this.loaded = true;
@@ -534,8 +604,7 @@ class SubscriptionsManager {
       throw error;
     }
 
-    const plainObj = { subPubkeys: Array.from(this.subscribedPubkeys) };
-    const plainStr = JSON.stringify(plainObj);
+    const plainStr = serializeSubscriptionTagMatrix(this.subscribedPubkeys);
 
     const encryptors = [];
     const registerEncryptor = (scheme, handler) => {
@@ -604,7 +673,9 @@ class SubscriptionsManager {
         ? "nip44_v2"
         : encryptionScheme === "nip44"
           ? "nip44"
-          : undefined;
+          : encryptionScheme === "nip04"
+            ? "nip04"
+            : undefined;
 
     const evt = buildSubscriptionListEvent({
       pubkey: userPubkey,
diff --git a/js/userBlocks.js b/js/userBlocks.js
index fb95fc14..029dbb5e 100644
--- a/js/userBlocks.js
+++ b/js/userBlocks.js
@@ -159,6 +159,111 @@ function determineDecryptionOrder(event, availableSchemes) {
   return prioritized.length ? prioritized : available;
 }
 
+function serializeBlockListTagMatrix(values, ownerPubkey) {
+  const tags = [];
+  const seen = new Set();
+  const owner = normalizeHex(ownerPubkey);
+  const iterable = Array.isArray(values)
+    ? values
+    : values instanceof Set
+    ? Array.from(values)
+    : values && typeof values[Symbol.iterator] === "function"
+    ? Array.from(values)
+    : [];
+
+  for (const candidate of iterable) {
+    const normalized = normalizeHex(candidate);
+    if (!normalized || normalized === owner || seen.has(normalized)) {
+      continue;
+    }
+    seen.add(normalized);
+    tags.push(["p", normalized]);
+  }
+
+  return JSON.stringify(tags);
+}
+
+function parseBlockListPlaintext(plaintext, ownerPubkey) {
+  if (typeof plaintext !== "string" || !plaintext) {
+    return [];
+  }
+
+  let parsed;
+  try {
+    parsed = JSON.parse(plaintext);
+  } catch (error) {
+    userLogger.warn(
+      "[UserBlockList] Failed to parse block list ciphertext as JSON; treating as empty.",
+      error,
+    );
+    return [];
+  }
+
+  const owner = normalizeHex(ownerPubkey);
+
+  const extractFromTags = (tags) => {
+    const collected = [];
+    const seen = new Set();
+    for (const entry of tags) {
+      if (!Array.isArray(entry) || entry.length < 2) {
+        continue;
+      }
+      const label = typeof entry[0] === "string" ? entry[0].trim().toLowerCase() : "";
+      if (label !== "p") {
+        continue;
+      }
+      const normalized = normalizeHex(entry[1]);
+      if (!normalized || normalized === owner || seen.has(normalized)) {
+        continue;
+      }
+      seen.add(normalized);
+      collected.push(normalized);
+    }
+    return collected;
+  };
+
+  if (Array.isArray(parsed)) {
+    return extractFromTags(parsed);
+  }
+
+  if (parsed && typeof parsed === "object") {
+    if (Array.isArray(parsed.tags) && parsed.tags.length) {
+      return extractFromTags(parsed.tags);
+    }
+
+    const legacy = Array.isArray(parsed.blockedPubkeys) ? parsed.blockedPubkeys : [];
+    return legacy
+      .map((value) => normalizeHex(value))
+      .filter((value) => value && value !== owner);
+  }
+
+  return [];
+}
+
+function isUserBlockListEvent(event) {
+  if (!event || typeof event.kind !== "number") {
+    return false;
+  }
+
+  if (event.kind === 10000) {
+    return true;
+  }
+
+  if (event.kind === 30002) {
+    const tags = Array.isArray(event.tags) ? event.tags : [];
+    return tags.some(
+      (tag) =>
+        Array.isArray(tag) &&
+        typeof tag[0] === "string" &&
+        tag[0].trim().toLowerCase() === "d" &&
+        typeof tag[1] === "string" &&
+        tag[1].trim() === BLOCK_LIST_IDENTIFIER,
+    );
+  }
+
+  return false;
+}
+
 function decodeNpubToHex(npub) {
   if (typeof npub !== "string") {
     return null;
@@ -540,10 +645,9 @@ class UserBlockListManager {
 
     try {
       const filter = {
-        kinds: [30002],
+        kinds: [10000, 30002],
         authors: [normalized],
-        "#d": [BLOCK_LIST_IDENTIFIER],
-        limit: 1,
+        limit: 2,
       };
 
       if (since !== null) {
@@ -603,7 +707,10 @@ class UserBlockListManager {
               settled = true;
               clearTimeout(timer);
               const events = Array.isArray(result)
-                ? result.filter((event) => event && event.pubkey === normalized)
+                ? result.filter(
+                    (event) =>
+                      event && event.pubkey === normalized && isUserBlockListEvent(event),
+                  )
                 : [];
               if (requireEvent && !events.length) {
                 const emptyError = new Error(
@@ -656,7 +763,10 @@ class UserBlockListManager {
         }
 
         const sorted = events
-          .filter((event) => event && event.pubkey === normalized)
+          .filter(
+            (event) =>
+              event && event.pubkey === normalized && isUserBlockListEvent(event),
+          )
           .sort((a, b) => (b?.created_at || 0) - (a?.created_at || 0));
 
         if (!sorted.length) {
@@ -810,21 +920,7 @@ class UserBlockListManager {
         }
 
         try {
-          const parsed = JSON.parse(decrypted);
-          const list = Array.isArray(parsed?.blockedPubkeys)
-            ? parsed.blockedPubkeys
-            : [];
-          const sanitized = list
-            .map((entry) => normalizeHex(entry))
-            .filter((candidate) => {
-              if (!candidate) {
-                return false;
-              }
-              if (candidate === normalized) {
-                return false;
-              }
-              return true;
-            });
+          const sanitized = parseBlockListPlaintext(decrypted, normalized);
           applyBlockedPubkeys(sanitized, {
             source,
             reason: "applied",
@@ -1336,7 +1432,7 @@ class UserBlockListManager {
         (candidate) => candidate && candidate !== normalized
       ),
     };
-    const plaintext = JSON.stringify(payload);
+    const plaintext = serializeBlockListTagMatrix(payload.blockedPubkeys, normalized);
 
     const encryptors = [];
     const registerEncryptor = (scheme, handler) => {
@@ -1397,7 +1493,9 @@ class UserBlockListManager {
         ? "nip44_v2"
         : encryptionScheme === "nip44"
           ? "nip44"
-          : undefined;
+          : encryptionScheme === "nip04"
+            ? "nip04"
+            : undefined;
 
     const event = buildBlockListEvent({
       pubkey: normalized,
diff --git a/tests/moderation/trusted-mute-lists.test.mjs b/tests/moderation/trusted-mute-lists.test.mjs
index 108d70c3..fd4ea988 100644
--- a/tests/moderation/trusted-mute-lists.test.mjs
+++ b/tests/moderation/trusted-mute-lists.test.mjs
@@ -103,18 +103,24 @@ test("trusted mute lists from seeds hide authors for anonymous viewers", async (
 
   await userBlocks.addBlock(mutedHex, seedHex);
 
-  const muteEvent = signedEvents.find((event) => event.kind === 10000);
+  const muteEvent = signedEvents.find(
+    (event) =>
+      event.kind === 10000 &&
+      Array.isArray(event.tags) &&
+      event.tags.some((tag) => Array.isArray(tag) && tag[0] === "p"),
+  );
   assert(muteEvent, "block list updates should publish a kind 10000 mute list event");
   assert(
-    Array.isArray(muteEvent.tags) &&
-      muteEvent.tags.some((tag) => Array.isArray(tag) && tag[0] === "p" && tag[1] === mutedHex),
+    muteEvent.tags.some((tag) => Array.isArray(tag) && tag[0] === "p" && tag[1] === mutedHex),
     "mute list event should include p-tags for blocked pubkeys",
   );
-  assert.equal(
-    publishedEvents.filter((event) => event?.kind === 10000).length,
-    1,
-    "mute list event should be published to relays",
+  const publishedMuteEvents = publishedEvents.filter(
+    (event) =>
+      event?.kind === 10000 &&
+      Array.isArray(event.tags) &&
+      event.tags.some((tag) => Array.isArray(tag) && tag[0] === "p"),
   );
+  assert(publishedMuteEvents.length >= 1, "mute list event should be published to relays");
 
   const { service } = createModerationServiceHarness(t, { userBlocks });
   service.refreshViewerFromClient = async () => {};
diff --git a/tests/subscriptions-manager.test.mjs b/tests/subscriptions-manager.test.mjs
index 441178c5..1656b15e 100644
--- a/tests/subscriptions-manager.test.mjs
+++ b/tests/subscriptions-manager.test.mjs
@@ -73,7 +73,7 @@ test("loadSubscriptions aggregates relay results when one rejects", async () =>
       async decrypt(_pubkey, ciphertext) {
         decryptCalls.push(ciphertext);
         if (ciphertext === "cipher-new") {
-          return JSON.stringify({ subPubkeys: ["pub-new"] });
+          return JSON.stringify([["p", "pub-new"]]);
         }
         return JSON.stringify({ subPubkeys: ["pub-old"] });
       },
@@ -179,7 +179,7 @@ test("loadSubscriptions falls back to nip44 when hinted", async () => {
     nip44: {
       async decrypt(_pubkey, ciphertext) {
         decryptCalls.nip44 += 1;
-        return JSON.stringify({ subPubkeys: ["pub-nip44"], hint: ciphertext });
+        return JSON.stringify([["p", "pub-nip44", ciphertext]]);
       },
     },
   };
@@ -264,7 +264,7 @@ test("loadSubscriptions handles nip44.v2 decryptors", async () => {
       v2: {
         async decrypt(_pubkey, ciphertext) {
           decryptCalls.nip44_v2 += 1;
-          return JSON.stringify({ subPubkeys: ["pub-nip44-v2"], hint: ciphertext });
+        return JSON.stringify([["p", "pub-nip44-v2"], ["t", ciphertext]]);
         },
       },
     },
@@ -354,14 +354,14 @@ test("loadSubscriptions prefers nip44 decryptors when both are available", async
     nip04: {
       async decrypt() {
         decryptCalls.nip04 += 1;
-        return JSON.stringify({ subPubkeys: ["pub-nip04"] });
+        return JSON.stringify([["p", "pub-nip04"]]);
       },
     },
     nip44: {
       v2: {
         async decrypt(_pubkey, ciphertext) {
           decryptCalls.nip44 += 1;
-          return JSON.stringify({ subPubkeys: ["pub-nip44-pref"], hint: ciphertext });
+          return JSON.stringify([["p", "pub-nip44-pref", ciphertext]]);
         },
       },
     },
@@ -443,7 +443,7 @@ test(
       pubkey: "user-pubkey-123",
       async nip04Decrypt(pubkey, ciphertext) {
         decryptCalls.push({ pubkey, ciphertext });
-        return JSON.stringify({ subPubkeys: ["pub-direct"] });
+        return JSON.stringify([["p", "pub-direct"]]);
       },
     });
 
@@ -712,7 +712,7 @@ test(
         encryptCalls[0],
         {
           pubkey: "user-pubkey-123",
-          plaintext: JSON.stringify({ subPubkeys: ["pub-direct"] }),
+          plaintext: JSON.stringify([["p", "pub-direct"]]),
         },
         "nip04Encrypt should receive the serialized subscription list",
       );
@@ -782,7 +782,7 @@ test("publishSubscriptionList prefers nip44 encryption when available", async ()
       assert.equal(pubkey, "user-pubkey-123");
       assert.equal(
         plaintext,
-        JSON.stringify({ subPubkeys: ["pub-one", "pub-two"] }),
+        JSON.stringify([["p", "pub-one"], ["p", "pub-two"]]),
       );
       return "cipher-nip44";
     },
@@ -871,8 +871,8 @@ test("publishSubscriptionList falls back to nip04 when nip44 fails", async () =>
       encryptCalls.nip04 += 1;
       assert.equal(pubkey, "user-pubkey-123");
       assert.equal(
-        plaintext,
-        JSON.stringify({ subPubkeys: ["pub-three"] }),
+      plaintext,
+      JSON.stringify([["p", "pub-three"]]),
       );
       return "cipher-nip04";
     },
@@ -894,10 +894,10 @@ test("publishSubscriptionList falls back to nip04 when nip44 fails", async () =>
     assert.equal(encryptCalls.nip04, 1, "nip04Encrypt should handle fallback");
     const signedEvent = signedEvents[0];
     const encryptedTags = signedEvent.tags.filter((tag) => tag[0] === "encrypted");
-    assert.equal(
-      encryptedTags.length,
-      0,
-      "fallback nip04 encryption should not advertise a nip44 tag",
+    assert.deepEqual(
+      encryptedTags,
+      [["encrypted", "nip04"]],
+      "fallback nip04 encryption should advertise nip04",
     );
     assert.equal(publishCalls.length, relayUrls.length, "event should publish to relays");
     assert.equal(manager.subsEventId, "signed-nip04-event");
diff --git a/tests/user-blocks.test.mjs b/tests/user-blocks.test.mjs
index baeef990..66c07d75 100644
--- a/tests/user-blocks.test.mjs
+++ b/tests/user-blocks.test.mjs
@@ -490,9 +490,7 @@ await (async () => {
   let latestEventId = "event-initial";
   let latestCreatedAt = 1_000;
 
-  const decryptPayloads = new Map([
-    [latestCiphertext, JSON.stringify({ blockedPubkeys: [] })],
-  ]);
+  const decryptPayloads = new Map([[latestCiphertext, JSON.stringify([])]]);
 
   const signedEvents = [];
 
@@ -541,9 +539,18 @@ await (async () => {
       } catch (error) {
         throw new Error(`unexpected payload ${plaintext}`);
       }
-      const blocked = Array.isArray(parsed?.blockedPubkeys)
-        ? [...parsed.blockedPubkeys].sort()
-        : [];
+      let blocked;
+      if (Array.isArray(parsed)) {
+        blocked = parsed
+          .filter((tag) => Array.isArray(tag) && tag.length >= 2 && tag[0] === "p")
+          .map((tag) => tag[1])
+          .filter((value) => typeof value === "string")
+          .sort();
+      } else if (Array.isArray(parsed?.blockedPubkeys)) {
+        blocked = [...parsed.blockedPubkeys].sort();
+      } else {
+        blocked = [];
+      }
       const cipher = `cipher:${JSON.stringify(blocked)}`;
       decryptPayloads.set(cipher, plaintext);
       return cipher;
@@ -607,11 +614,15 @@ await (async () => {
       "direct signer flows should never trigger extension permission prompts",
     );
 
-    const muteEvent = signedEvents.find((event) => event.kind === 10000);
+    const muteEvent = signedEvents.find(
+      (event) =>
+        event.kind === 10000 &&
+        Array.isArray(event.tags) &&
+        event.tags.some((tag) => Array.isArray(tag) && tag[0] === "p"),
+    );
     assert(muteEvent, "block list updates should publish a kind 10000 mute list event");
     assert(
-      Array.isArray(muteEvent.tags) &&
-        muteEvent.tags.some((tag) => Array.isArray(tag) && tag[0] === "p" && tag[1] === target),
+      muteEvent.tags.some((tag) => Array.isArray(tag) && tag[0] === "p" && tag[1] === target),
       "mute list event should include p-tags for blocked pubkeys",
     );
   } finally {
@@ -677,7 +688,7 @@ await (async () => {
       assert.equal(pubkey, actor);
       assert.equal(
         plaintext,
-        JSON.stringify({ blockedPubkeys: [blocked] }),
+        JSON.stringify([["p", blocked]]),
       );
       return "cipher-nip44";
     },
@@ -763,7 +774,7 @@ await (async () => {
       assert.equal(pubkey, actor);
       assert.equal(
         plaintext,
-        JSON.stringify({ blockedPubkeys: [blocked] }),
+        JSON.stringify([["p", blocked]]),
       );
       return "cipher-nip04";
     },
@@ -787,10 +798,10 @@ await (async () => {
     );
     assert.equal(encryptCalls.nip04, 1, "nip04Encrypt should handle fallback");
     const encryptedTags = signedEvents[0].tags.filter((tag) => tag[0] === "encrypted");
-    assert.equal(
-      encryptedTags.length,
-      0,
-      "fallback nip04 encryption should not advertise a nip44 tag",
+    assert.deepEqual(
+      encryptedTags,
+      [["encrypted", "nip04"]],
+      "fallback nip04 encryption should advertise nip04",
     );
     assert.equal(publishCalls.length, 1, "event should publish to the available relay");
   } finally {
@@ -834,7 +845,7 @@ await (async () => {
       v2: {
         async decrypt(_pubkey, ciphertext) {
           decryptCalls.nip44 += 1;
-          return JSON.stringify({ blockedPubkeys: [blocked], hint: ciphertext });
+          return JSON.stringify([["p", blocked, ciphertext]]);
         },
       },
     },