diff --git a/src/idz/userdb/decoder/createProfile.ts b/src/idz/userdb/decoder/createProfile.ts
index 06d18d3..b7479c9 100644
--- a/src/idz/userdb/decoder/createProfile.ts
+++ b/src/idz/userdb/decoder/createProfile.ts
@@ -1,9 +1,8 @@
-import iconv from "iconv-lite";
-
 import { car } from "./_car";
 import { chara } from "./_chara";
 import { CreateProfileRequest } from "../request/createProfile";
 import { AimeId } from "../../../model";
+import { readAsciiStr, readSjisStr } from "../../util/bin";
 
 createProfile.msgCode = 0x0066;
 createProfile.msgLen = 0x00c0;
@@ -12,11 +11,8 @@ export function createProfile(buf: Buffer): CreateProfileRequest {
   return {
     type: "create_profile_req",
     aimeId: buf.readInt32LE(0x0004) as AimeId,
-    luid: buf.slice(0x0008, buf.indexOf("\0", 0x0008)).toString("ascii"),
-    name: iconv.decode(
-      buf.slice(0x001e, buf.indexOf("\0", 0x001e)),
-      "shift_jis"
-    ),
+    luid: readAsciiStr(buf, 0x0008, 0x001e),
+    name: readSjisStr(buf, 0x001e, 0x0034),
     field_0034: buf.readUInt32LE(0x0034),
     car: car(buf.slice(0x0040, 0x00a0)),
     chara: chara(buf.slice(0x00a0, 0x00b4)),
diff --git a/src/idz/userdb/decoder/createTeam.ts b/src/idz/userdb/decoder/createTeam.ts
index 9b96248..ef27ef3 100644
--- a/src/idz/userdb/decoder/createTeam.ts
+++ b/src/idz/userdb/decoder/createTeam.ts
@@ -1,7 +1,6 @@
-import iconv from "iconv-lite";
-
 import { CreateTeamRequest } from "../request/createTeam";
 import { AimeId } from "../../../model";
+import { readAsciiStr, readSjisStr } from "../../util/bin";
 
 createTeam.msgCode = 0x0071;
 createTeam.msgLen = 0x0050;
@@ -10,15 +9,12 @@ export function createTeam(buf: Buffer): CreateTeamRequest {
   return {
     type: "create_team_req",
     aimeId: buf.readUInt32LE(0x0004) as AimeId,
-    teamName: iconv.decode(
-      buf.slice(0x0008, buf.indexOf("\0", 0x0008)),
-      "shift_jis"
-    ),
+    teamName: readSjisStr(buf, 0x0008, 0x0028),
     field_0028: buf.readUInt16LE(0x0028),
     field_002C: buf.readUInt32LE(0x002c),
     nameBg: buf.readUInt8(0x0030),
     field_0032: buf.readUInt16LE(0x0032),
     prevTeamId: buf.readUInt32LE(0x0034),
-    pcbId: buf.slice(0x0038, buf.indexOf("\0", 0x0038)).toString("ascii"),
+    pcbId: readAsciiStr(buf, 0x0038, 0x0050),
   };
 }
diff --git a/src/idz/userdb/decoder/loadProfile.ts b/src/idz/userdb/decoder/loadProfile.ts
index 54c6e9b..741db65 100644
--- a/src/idz/userdb/decoder/loadProfile.ts
+++ b/src/idz/userdb/decoder/loadProfile.ts
@@ -3,6 +3,7 @@ import {
   LoadProfileRequest3,
 } from "../request/loadProfile";
 import { AimeId } from "../../../model";
+import { readAsciiStr } from "../../util/bin";
 
 loadProfile2.msgCode = 0x0067;
 loadProfile2.msgLen = 0x0020;
@@ -12,7 +13,7 @@ export function loadProfile2(buf: Buffer): LoadProfileRequest2 {
     type: "load_profile_req",
     format: 2,
     aimeId: buf.readUInt32LE(0x0004) as AimeId,
-    luid: buf.slice(0x0008, buf.indexOf("\0", 0x0008)).toString("ascii"),
+    luid: readAsciiStr(buf, 0x0008, 0x0020),
   };
 }
 
@@ -24,6 +25,6 @@ export function loadProfile3(buf: Buffer): LoadProfileRequest3 {
     type: "load_profile_req",
     format: 3,
     aimeId: buf.readUInt32LE(0x0004) as AimeId,
-    luid: buf.slice(0x0008, buf.indexOf("\0", 0x0008)).toString("ascii"),
+    luid: readAsciiStr(buf, 0x0008, 0x0020),
   };
 }
diff --git a/src/idz/userdb/decoder/lockProfile.ts b/src/idz/userdb/decoder/lockProfile.ts
index e461e3d..e106953 100644
--- a/src/idz/userdb/decoder/lockProfile.ts
+++ b/src/idz/userdb/decoder/lockProfile.ts
@@ -1,3 +1,4 @@
+import { readAsciiStr } from "../../util/bin";
 import { LockProfileRequest } from "../request/lockProfile";
 
 lockProfile.msgCode = 0x0069;
@@ -7,7 +8,7 @@ export function lockProfile(buf: Buffer): LockProfileRequest {
   return {
     type: "lock_profile_req",
     aimeId: buf.readUInt32LE(0x0004),
-    pcbId: buf.slice(0x0008, buf.indexOf("\0", 0x0008)).toString("ascii"),
+    pcbId: readAsciiStr(buf, 0x0008, 0x0018),
     field_0018: buf.readUInt16LE(0x0018),
   };
 }
diff --git a/src/idz/userdb/decoder/lockProfileExtend.ts b/src/idz/userdb/decoder/lockProfileExtend.ts
index f9e6df7..98aea4a 100644
--- a/src/idz/userdb/decoder/lockProfileExtend.ts
+++ b/src/idz/userdb/decoder/lockProfileExtend.ts
@@ -1,5 +1,6 @@
 import { LockProfileExtendRequest } from "../request/lockProfileExtend";
 import { AimeId } from "../../../model";
+import { readAsciiStr } from "../../util/bin";
 
 lockProfileExtend.msgCode = 0x006d;
 lockProfileExtend.msgLen = 0x0020;
@@ -8,6 +9,6 @@ export function lockProfileExtend(buf: Buffer): LockProfileExtendRequest {
   return {
     type: "lock_profile_extend_req",
     aimeId: buf.readUInt32LE(0x0004) as AimeId,
-    luid: buf.slice(0x0008, buf.indexOf("\0")).toString("ascii"),
+    luid: readAsciiStr(buf, 0x0008, 0x0020),
   };
 }
diff --git a/src/idz/userdb/decoder/saveNewCar.ts b/src/idz/userdb/decoder/saveNewCar.ts
index ca63ed3..48cd570 100644
--- a/src/idz/userdb/decoder/saveNewCar.ts
+++ b/src/idz/userdb/decoder/saveNewCar.ts
@@ -1,5 +1,6 @@
 import { car } from "./_car";
 import { SaveNewCarRequest } from "../request/saveNewCar";
+import { readAsciiStr } from "../../util/bin";
 import { AimeId } from "../../../model";
 
 saveNewCar.msgCode = 0x0079;
@@ -9,7 +10,7 @@ export function saveNewCar(buf: Buffer): SaveNewCarRequest {
   return {
     type: "save_new_car_req",
     aimeId: buf.readUInt32LE(0x0004) as AimeId,
-    luid: buf.slice(0x0008, buf.indexOf(0, 0x0008)).toString("ascii"),
+    luid: readAsciiStr(buf, 0x0008, 0x001e),
     car: car(buf.slice(0x0020, 0x0080)),
     field_0080: buf.readUInt32LE(0x0080),
   };
diff --git a/src/idz/userdb/decoder/updateTeamLeader.ts b/src/idz/userdb/decoder/updateTeamLeader.ts
index 35d5660..2a88823 100644
--- a/src/idz/userdb/decoder/updateTeamLeader.ts
+++ b/src/idz/userdb/decoder/updateTeamLeader.ts
@@ -2,6 +2,7 @@ import { ExtId } from "../model/base";
 import { Team } from "../model/team";
 import { UpdateTeamLeaderRequest } from "../request/updateTeamLeader";
 import { AimeId } from "../../../model";
+import { readAsciiStr } from "../../util/bin";
 
 updateTeamLeader.msgCode = 0x008a;
 updateTeamLeader.msgLen = 0x0020;
@@ -11,6 +12,6 @@ export function updateTeamLeader(buf: Buffer): UpdateTeamLeaderRequest {
     type: "update_team_leader_req",
     aimeId: buf.readUInt32LE(0x0004) as AimeId,
     teamExtId: buf.readUInt32LE(0x0008) as ExtId<Team>,
-    field_000C: buf.slice(0x000c, buf.indexOf("\0", 0x000c)).toString("ascii"),
+    field_000C: readAsciiStr(buf, 0x000c, 0x0020),
   };
 }
diff --git a/src/idz/userdb/encoder/_team.ts b/src/idz/userdb/encoder/_team.ts
index fcd6e15..5ca8584 100644
--- a/src/idz/userdb/encoder/_team.ts
+++ b/src/idz/userdb/encoder/_team.ts
@@ -1,5 +1,4 @@
-import iconv from "iconv-lite";
-
+import { writeSjisStr } from "../../util/bin";
 import { CreateAutoTeamResponse } from "../response/createAutoTeam";
 import { LoadTeamResponse } from "../response/loadTeam";
 import { encodeChara } from "./_chara";
@@ -15,9 +14,9 @@ export function _team(res: CreateAutoTeamResponse | LoadTeamResponse) {
 
   const leader = res.members.find(item => item.leader === true);
   buf.writeUInt32LE(res.team.extId, 0x000c);
-  iconv.encode(leader ? leader.profile.name : "Error\0", "shift_jis").copy(buf, 0x0010);
-  iconv.encode(res.team.name, "shift_jis").copy(buf, 0x0024);
-  iconv.encode(process.env.SHOP_NAME ? process.env.SHOP_NAME : "\0", "shift_jis").copy(buf, 0x0044);
+  writeSjisStr(buf, 0x0010, 0x0024, leader ? leader.profile.name : "Error");
+  writeSjisStr(buf, 0x0024, 0x0044, res.team.name);
+  writeSjisStr(buf, 0x0044, 0x00d8, process.env.SHOP_NAME || "");
   buf.writeUInt32LE(res.team.nameBg, 0x00d8);
   buf.writeUInt32LE(res.team.nameFx, 0x00dc);
   buf.fill(0xff, 0x00e0, 0x00f9); // Bitset: Unlocked BGs probably
@@ -36,7 +35,7 @@ export function _team(res: CreateAutoTeamResponse | LoadTeamResponse) {
     const accessTime = (profile.accessTime.getTime() / 1000) | 0;
 
     buf.writeInt32LE(profile.aimeId, base + 0x0000);
-    iconv.encode(profile.name + "\0", "shift_jis").copy(buf, base + 0x0004);
+    writeSjisStr(buf, 0x0004, 0x0018, profile.name);
     buf.writeInt32LE(profile.lv, base + 0x0018);
     buf.writeInt32LE(0, base + 0x0024); // Month points, TODO
     buf.writeUInt32LE(accessTime, base + 0x0034);
diff --git a/src/idz/userdb/encoder/loadGeneralReward.ts b/src/idz/userdb/encoder/loadGeneralReward.ts
index aec55a1..8a04079 100644
--- a/src/idz/userdb/encoder/loadGeneralReward.ts
+++ b/src/idz/userdb/encoder/loadGeneralReward.ts
@@ -1,6 +1,5 @@
-import iconv from "iconv-lite";
-
 import { LoadGeneralRewardResponse } from "../response/loadGeneralReward";
+import { writeSjisStr } from "../../util/bin";
 
 export function loadGeneralReward(res: LoadGeneralRewardResponse) {
   const buf = Buffer.alloc(0x0330);
@@ -15,7 +14,7 @@ export function loadGeneralReward(res: LoadGeneralRewardResponse) {
     const item = res.items[i];
     const base = 0x04 + 0x50 * i;
 
-    iconv.encode(item.field_04, "shift_jis").copy(buf, base + 0x04);
+    writeSjisStr(buf, base + 0x04, base + 0x2c, item.field_04);
     buf.writeUInt32LE(item.field_2C, base + 0x2c);
     buf.writeUInt8(item.field_38, base + 0x38);
     buf.writeUInt8(item.field_39, base + 0x39);
diff --git a/src/idz/userdb/encoder/loadProfile2.ts b/src/idz/userdb/encoder/loadProfile2.ts
index 6c4fd95..7f70c5b 100644
--- a/src/idz/userdb/encoder/loadProfile2.ts
+++ b/src/idz/userdb/encoder/loadProfile2.ts
@@ -1,10 +1,9 @@
-import iconv from "iconv-lite";
-
 import { encodeBitmap } from "./_bitmap";
 import { encodeCar } from "./_car";
 import { encodeChara } from "./_chara";
 import { encodeMission } from "./_mission";
 import { LoadProfileResponse2 } from "../response/loadProfile";
+import { writeSjisStr } from "../../util/bin";
 
 export function loadProfile2(res: LoadProfileResponse2) {
   const buf = Buffer.alloc(0x0d30);
@@ -87,7 +86,7 @@ export function loadProfile2(res: LoadProfileResponse2) {
   buf.writeUInt32LE(res.settings.pack, 0x03d8);
   buf.writeUInt32LE(res.dpoint, 0x03e8);
   buf.writeUInt32LE(res.fame, 0x0404);
-  iconv.encode(res.name + "\0", "shift_jis").copy(buf, 0x03ee);
+  writeSjisStr(buf, 0x03ee, 0x40e, res.name);
   buf.writeUInt8(res.story.y, 0x0670);
   buf.writeUInt16LE(res.story.x, 0x06bc);
   encodeMission(res.missions.solo).copy(buf, 0x06e4);
diff --git a/src/idz/userdb/encoder/loadProfile3.ts b/src/idz/userdb/encoder/loadProfile3.ts
index 5f50ffd..53290b0 100644
--- a/src/idz/userdb/encoder/loadProfile3.ts
+++ b/src/idz/userdb/encoder/loadProfile3.ts
@@ -1,10 +1,9 @@
-import iconv from "iconv-lite";
-
 import { encodeBitmap } from "./_bitmap";
 import { encodeCar } from "./_car";
 import { encodeChara } from "./_chara";
 import { encodeMission } from "./_mission";
 import { LoadProfileResponse3 } from "../response/loadProfile";
+import { writeSjisStr } from "../../util/bin";
 
 export function loadProfile3(res: LoadProfileResponse3) {
   const buf = Buffer.alloc(0x0ea0);
@@ -87,7 +86,7 @@ export function loadProfile3(res: LoadProfileResponse3) {
   buf.writeUInt32LE(res.settings.pack, 0x04b4);
   buf.writeUInt32LE(res.dpoint, 0x04c4);
   buf.writeUInt32LE(res.fame, 0x04e0);
-  iconv.encode(res.name + "\0", "shift_jis").copy(buf, 0x04ca);
+  writeSjisStr(buf, 0x04ca, 0x04ea, res.name);
   buf.writeUInt8(res.story.y, 0x080c);
   buf.writeUInt16LE(res.story.x, 0x0828);
   encodeMission(res.missions.solo).copy(buf, 0x0858);
diff --git a/src/idz/userdb/encoder/loadTopTen.ts b/src/idz/userdb/encoder/loadTopTen.ts
index 50e5342..213fe5b 100644
--- a/src/idz/userdb/encoder/loadTopTen.ts
+++ b/src/idz/userdb/encoder/loadTopTen.ts
@@ -1,5 +1,4 @@
-import iconv from "iconv-lite";
-
+import { writeSjisStr } from "../../util/bin";
 import { LoadTopTenResponse } from "../response/loadTopTen";
 
 export function loadTopTen(res: LoadTopTenResponse): Buffer {
@@ -49,9 +48,9 @@ export function loadTopTen(res: LoadTopTenResponse): Buffer {
       buf.writeUInt8(row.field_0E ? 1 : 0, innerOff + 0x000e); // Boolean
       buf.writeUInt8(row.field_0F ? 1 : 0, innerOff + 0x000f); // Boolean
       buf.writeUInt8(row.field_10, innerOff + 0x0010);
-      iconv.encode(row.driverName, "shift_jis").copy(buf, innerOff + 0x0014);
-      iconv.encode(row.team.name, "shift_jis").copy(buf, innerOff + 0x0028);
-      iconv.encode(row.shopName, "shift_jis").copy(buf, innerOff + 0x0048);
+      writeSjisStr(buf, innerOff + 0x0014, innerOff + 0x0028, row.driverName);
+      writeSjisStr(buf, innerOff + 0x0028, innerOff + 0x0048, row.team.name);
+      writeSjisStr(buf, innerOff + 0x0048, innerOff + 0x0074, row.shopName);
       buf.writeUInt32LE(row.team.nameBg, innerOff + 0x0074);
       buf.writeUInt16LE(row.team.nameFx, innerOff + 0x0078);
       buf.writeUInt8(row.field_7C, innerOff + 0x007c);
@@ -70,7 +69,7 @@ export function loadTopTen(res: LoadTopTenResponse): Buffer {
       buf.writeUInt8(trailer.courseId, offset + 0x02);
       buf.writeUInt8(trailer.isNight ? 1 : 0, offset + 0x03);
       buf.writeUInt32LE(trailer.totalMsec, offset + 0x04);
-      iconv.encode(trailer.name, "shift_jis").copy(buf, offset + 0x08);
+      writeSjisStr(buf, offset + 0x08, offset + 0x1c, trailer.name);
     } else {
       buf.writeUInt8(0xff, offset + 0x02);
     }
diff --git a/src/idz/userdb/encoder/updateProvisionalStoreRank.ts b/src/idz/userdb/encoder/updateProvisionalStoreRank.ts
index cad6701..23b9a43 100644
--- a/src/idz/userdb/encoder/updateProvisionalStoreRank.ts
+++ b/src/idz/userdb/encoder/updateProvisionalStoreRank.ts
@@ -1,6 +1,5 @@
-import iconv from "iconv-lite";
-
 import { UpdateProvisionalStoreRankResponse } from "../response/updateProvisionalStoreRank";
+import { writeSjisStr } from "../../util/bin";
 
 export function updateProvisionalStoreRank(
   res: UpdateProvisionalStoreRankResponse
@@ -16,8 +15,8 @@ export function updateProvisionalStoreRank(
     if (row !== undefined) {
       buf.writeInt16LE(row.field_0000, offset + 0x0000);
       buf.writeInt32LE(row.field_0004, offset + 0x0004);
-      iconv.encode(row.field_0010, "shift_jis").copy(buf, offset + 0x0010);
-      iconv.encode(row.field_003B, "shift_jis").copy(buf, offset + 0x003b);
+      writeSjisStr(buf, offset + 0x0010, offset + 0x003b, row.field_0010);
+      writeSjisStr(buf, offset + 0x003b, offset + 0x0044, row.field_003B);
     }
   }