diff --git a/src/decrypt/qmc_key.test.ts b/src/decrypt/qmc_key.test.ts
new file mode 100644
index 0000000..4584f9e
--- /dev/null
+++ b/src/decrypt/qmc_key.test.ts
@@ -0,0 +1,30 @@
+import {DecryptKey, simpleMakeKey,} from "@/decrypt/qmc_key";
+import fs from "fs";
+
+test("key dec: make simple key", () => {
+  expect(
+    simpleMakeKey(106, 8)
+  ).toStrictEqual(
+    [0x69, 0x56, 0x46, 0x38, 0x2b, 0x20, 0x15, 0x0b]
+  )
+})
+
+function loadTestDataKeyDecrypt(name: string): {
+  cipherText: Uint8Array,
+  clearText: Uint8Array
+} {
+  return {
+    cipherText: fs.readFileSync(`testdata/${name}_key_raw.bin`),
+    clearText: fs.readFileSync(`testdata/${name}_key.bin`)
+  }
+}
+
+test("key dec: real file", async () => {
+  const cases = ["mflac_map", "mgg_map", "mflac0_rc4"]
+  for (const name of cases) {
+    const {clearText, cipherText} = loadTestDataKeyDecrypt(name)
+    const buf = DecryptKey(cipherText)
+
+    expect(buf).toStrictEqual(clearText)
+  }
+})
diff --git a/src/decrypt/qmc_key.ts b/src/decrypt/qmc_key.ts
new file mode 100644
index 0000000..ba487ba
--- /dev/null
+++ b/src/decrypt/qmc_key.ts
@@ -0,0 +1,103 @@
+import {TeaCipher} from "@/utils/tea";
+
+export function simpleMakeKey(salt: number, length: number): number[] {
+  const keyBuf: number[] = []
+  for (let i = 0; i < length; i++) {
+    const tmp = Math.tan(salt + i * 0.1)
+    keyBuf[i] = 0xff & (Math.abs(tmp) * 100.0)
+  }
+  return keyBuf
+}
+
+const SALT_LEN = 2
+const ZERO_LEN = 7
+
+function decryptTencentTea(inBuf: Uint8Array, key: Uint8Array): Uint8Array {
+  if (inBuf.length % 8 != 0) {
+    throw Error("inBuf size not a multiple of the block size")
+  }
+  if (inBuf.length < 16) {
+    throw Error("inBuf size too small")
+  }
+
+  const blk = new TeaCipher(key, 32)
+
+  const tmpBuf = new Uint8Array(8);
+  const tmpView = new DataView(tmpBuf.buffer);
+
+  blk.decrypt(tmpView, new DataView(inBuf.buffer, inBuf.byteOffset, 8))
+
+  const nPadLen = tmpBuf[0] & 0x7;//只要最低三位
+  /*密文格式:PadLen(1byte)+Padding(var,0-7byte)+Salt(2byte)+Body(var byte)+Zero(7byte)*/
+  const outLen = inBuf.length - 1 /*PadLen*/ - nPadLen - SALT_LEN - ZERO_LEN;
+  const outBuf = new Uint8Array(outLen)
+
+  let ivPrev = new Uint8Array(8);
+  let ivCur = inBuf.slice(0, 8); // init iv
+  let inBufPos = 8;
+
+
+  // 跳过 Padding Len 和 Padding
+  let tmpIdx = 1 + nPadLen;
+
+  // CBC IV 处理
+  const cryptBlock = () => {
+    ivPrev = ivCur;
+    ivCur = inBuf.slice(inBufPos, inBufPos + 8)
+    for (let j = 0; j < 8; j++) {
+      tmpBuf[j] ^= ivCur[j]
+    }
+    blk.decrypt(tmpView, tmpView)
+    inBufPos += 8;
+    tmpIdx = 0;
+  }
+
+  // 跳过 Salt
+  for (let i = 1; i <= SALT_LEN;) {
+    if (tmpIdx < 8) {
+      tmpIdx++;
+      i++;
+    } else {
+      cryptBlock()
+    }
+  }
+
+  // 还原明文
+  let outBufPos = 0;
+  while (outBufPos < outLen) {
+    if (tmpIdx < 8) {
+      outBuf[outBufPos] = tmpBuf[tmpIdx] ^ ivPrev[tmpIdx];
+      outBufPos++
+      tmpIdx++;
+    } else {
+      cryptBlock()
+    }
+  }
+
+  // 校验Zero
+  for (let i = 1; i <= ZERO_LEN; i++) {
+    if (tmpBuf[tmpIdx] != ivPrev[tmpIdx]) {
+      throw Error("zero check failed")
+    }
+  }
+  return outBuf
+}
+
+export function DecryptKey(raw: Uint8Array): Uint8Array {
+  const rawDec = Buffer.from(raw.toString(), 'base64')
+  let n = rawDec.length;
+  if (n < 16) {
+    throw Error("key length is too short")
+  }
+
+  const simpleKey = simpleMakeKey(106, 8)
+  let teaKey = new Uint8Array(16);
+  for (let i = 0; i < 8; i++) {
+    teaKey[i << 1] = simpleKey[i];
+    teaKey[(i << 1) + 1] = rawDec[i];
+  }
+  const sub = decryptTencentTea(rawDec.subarray(8), teaKey)
+  rawDec.set(sub, 8)
+  return rawDec.subarray(0, 8 + sub.length)
+
+}
diff --git a/testdata/mflac0_rc4_key.bin b/testdata/mflac0_rc4_key.bin
new file mode 100644
index 0000000..3bd0914
--- /dev/null
+++ b/testdata/mflac0_rc4_key.bin
@@ -0,0 +1 @@
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
\ No newline at end of file
diff --git a/testdata/mflac0_rc4_key_raw.bin b/testdata/mflac0_rc4_key_raw.bin
new file mode 100644
index 0000000..39c8a3b
--- /dev/null
+++ b/testdata/mflac0_rc4_key_raw.bin
@@ -0,0 +1 @@
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
\ No newline at end of file
diff --git a/testdata/mflac0_rc4_raw.bin b/testdata/mflac0_rc4_raw.bin
new file mode 100644
index 0000000..fd7e4af
Binary files /dev/null and b/testdata/mflac0_rc4_raw.bin differ
diff --git a/testdata/mflac0_rc4_suffix.bin b/testdata/mflac0_rc4_suffix.bin
new file mode 100644
index 0000000..63a168a
Binary files /dev/null and b/testdata/mflac0_rc4_suffix.bin differ
diff --git a/testdata/mflac0_rc4_target.bin b/testdata/mflac0_rc4_target.bin
new file mode 100644
index 0000000..a7f86c7
Binary files /dev/null and b/testdata/mflac0_rc4_target.bin differ
diff --git a/testdata/mflac_map_key.bin b/testdata/mflac_map_key.bin
index e69de29..7fd7a72 100644
--- a/testdata/mflac_map_key.bin
+++ b/testdata/mflac_map_key.bin
@@ -0,0 +1 @@
+yw7xWOyNQ8585Jwx3hjB49QLPKi38F89awnrQ0fq66NT9TDq1ppHNrFqhaDrU5AFk916D58I53h86304GqOFCCyFzBem68DqiXJ81bILEQwG3P3MOnoNzM820kNW9Lv9IJGNn9Xo497p82BLTm4hAX8JLBs0T2pilKvT429sK9jfg508GSk4d047Jxdz5Fou4aa33OkyFRBU3x430mgNBn04Lc9BzXUI2IGYXv3FGa9qE4Vb54kSjVv8ogbg47j3
\ No newline at end of file
diff --git a/testdata/mflac_map_key_raw.bin b/testdata/mflac_map_key_raw.bin
index e69de29..f088613 100644
--- a/testdata/mflac_map_key_raw.bin
+++ b/testdata/mflac_map_key_raw.bin
@@ -0,0 +1 @@
+eXc3eFdPeU6+3f7GVeF35bMpIEIQj5JWOWt7G+jsR68Hx3BUFBavkTQ8dpPdP0XBIwPe+OfdsnTGVQqPyg3GCtQSrkgA0mwSQdr4DPzKLkEZFX+Cf1V6ChyipOuC6KT37eAxWMdV1UHf9/OCvydr1dc6SWK1ijRUcP6IAHQhiB+mZLay7XXrSPo32WjdBkn9c9sa2SLtI48atj5kfZ4oOq6QGeld2JA3Z+3wwCe6uTHthKaEHY8ufDYodEe3qqrjYpzkdx55pCtxCQa1JiNqFmJigWm4m3CDzhuJ7YqnjbD+mXxLi7BP1+z4L6nccE2h+DGHVqpGjR9+4LBpe4WHB4DrAzVp2qQRRQJxeHd1v88=
\ No newline at end of file
diff --git a/testdata/mgg_map_key.bin b/testdata/mgg_map_key.bin
index e69de29..fecf089 100644
--- a/testdata/mgg_map_key.bin
+++ b/testdata/mgg_map_key.bin
@@ -0,0 +1 @@
+zGxNk54pKJ0hDkAo80wHE80ycSWQ7z4m4E846zVy2sqCn14F42Y5S7GqeR11WpOV75sDLbE5dFP992t88l0pHy1yAQ49YK6YX6c543drBYLo55Hc4Y0Fyic6LQPiGqu2bG31r8vaq9wS9v63kg0X5VbnOD6RhO4t0RRhk3ajrA7p0iIy027z0L70LZjtw6E18H0D41nz6ASTx71otdF9z1QNC0JmCl51xvnb39zPExEXyKkV47S6QsK5hFh884QJ
\ No newline at end of file
diff --git a/testdata/mgg_map_key_raw.bin b/testdata/mgg_map_key_raw.bin
index e69de29..bea6675 100644
--- a/testdata/mgg_map_key_raw.bin
+++ b/testdata/mgg_map_key_raw.bin
@@ -0,0 +1 @@
+ekd4Tms1NHC53JEDO/AKVyF+I0bj0hHB7CZeoLDGSApaQB9Oo/pJTBGA/RO+nk5RXLXdHsffLiY4e8kt3LNo6qMl7S89vkiSFxx4Uoq4bGDJ7Jc+bYL6lLsa3M4sBvXS4XcPChrMDz+LmrJMGG6ua2fYyIz1d6TCRUBf1JJgCIkBbDAEeMVYc13qApitiz/apGAPmAnveCaDhfD5GxWsF+RfQ2OcnvrnIXe80Feh/0jx763DlsOBI3eIede6t5zYHokWkZmVEF1jMrnlvsgbQK2EzUWMblmLMsTKNILyZazEoKUyulqmyLO/c/KYE+USPOXPcbjlYFmLhSGHK7sQB5aBR153Yp+xh61ooh2NGAA=
\ No newline at end of file