diff --git a/packages/backend/src/misc/id/aid.ts b/packages/backend/src/misc/id/aid.ts
deleted file mode 100644
index a12360360b..0000000000
--- a/packages/backend/src/misc/id/aid.ts
+++ /dev/null
@@ -1,25 +0,0 @@
-// AID
-// 長さ8の[2000年1月1日からの経過ミリ秒をbase36でエンコードしたもの] + 長さ2の[ノイズ文字列]
-
-import * as crypto from "node:crypto";
-
-const TIME2000 = 946684800000;
-let counter = crypto.randomBytes(2).readUInt16LE(0);
-
-function getTime(time: number) {
-	time = time - TIME2000;
-	if (time < 0) time = 0;
-
-	return time.toString(36).padStart(8, "0");
-}
-
-function getNoise() {
-	return counter.toString(36).padStart(2, "0").slice(-2);
-}
-
-export function genAid(date: Date): string {
-	const t = date.getTime();
-	if (isNaN(t)) throw "Failed to create AID: Invalid Date";
-	counter++;
-	return getTime(t) + getNoise();
-}
diff --git a/packages/backend/src/misc/id/meid.ts b/packages/backend/src/misc/id/meid.ts
deleted file mode 100644
index ee78eb8d14..0000000000
--- a/packages/backend/src/misc/id/meid.ts
+++ /dev/null
@@ -1,26 +0,0 @@
-const CHARS = "0123456789abcdef";
-
-function getTime(time: number) {
-	if (time < 0) time = 0;
-	if (time === 0) {
-		return CHARS[0];
-	}
-
-	time += 0x800000000000;
-
-	return time.toString(16).padStart(12, CHARS[0]);
-}
-
-function getRandom() {
-	let str = "";
-
-	for (let i = 0; i < 12; i++) {
-		str += CHARS[Math.floor(Math.random() * CHARS.length)];
-	}
-
-	return str;
-}
-
-export function genMeid(date: Date): string {
-	return getTime(date.getTime()) + getRandom();
-}
diff --git a/packages/backend/src/misc/id/meidg.ts b/packages/backend/src/misc/id/meidg.ts
deleted file mode 100644
index 4fd39a8b41..0000000000
--- a/packages/backend/src/misc/id/meidg.ts
+++ /dev/null
@@ -1,28 +0,0 @@
-const CHARS = "0123456789abcdef";
-
-//  4bit Fixed hex value 'g'
-// 44bit UNIX Time ms in Hex
-// 48bit Random value in Hex
-
-function getTime(time: number) {
-	if (time < 0) time = 0;
-	if (time === 0) {
-		return CHARS[0];
-	}
-
-	return time.toString(16).padStart(11, CHARS[0]);
-}
-
-function getRandom() {
-	let str = "";
-
-	for (let i = 0; i < 12; i++) {
-		str += CHARS[Math.floor(Math.random() * CHARS.length)];
-	}
-
-	return str;
-}
-
-export function genMeidg(date: Date): string {
-	return `g${getTime(date.getTime())}${getRandom()}`;
-}
diff --git a/packages/backend/src/misc/id/object-id.ts b/packages/backend/src/misc/id/object-id.ts
deleted file mode 100644
index 45822f0acc..0000000000
--- a/packages/backend/src/misc/id/object-id.ts
+++ /dev/null
@@ -1,26 +0,0 @@
-const CHARS = "0123456789abcdef";
-
-function getTime(time: number) {
-	if (time < 0) time = 0;
-	if (time === 0) {
-		return CHARS[0];
-	}
-
-	time = Math.floor(time / 1000);
-
-	return time.toString(16).padStart(8, CHARS[0]);
-}
-
-function getRandom() {
-	let str = "";
-
-	for (let i = 0; i < 16; i++) {
-		str += CHARS[Math.floor(Math.random() * CHARS.length)];
-	}
-
-	return str;
-}
-
-export function genObjectId(date: Date): string {
-	return getTime(date.getTime()) + getRandom();
-}