refactor(decrypt/qmc): typescript qmc mask

src/decrypt/qmc.js

@@ -1,4 +1,4 @@
-import {QmcMaskCreate58, QmcMaskDetectMflac, QmcMaskDetectMgg, QmcMaskGetDefault} from "./qmcMask";
+import {QmcMask, QmcMaskDetectMflac, QmcMaskDetectMgg, QmcMaskGetDefault} from "./qmcMask";
 import {fromByteArray as Base64Encode, toByteArray as Base64Decode} from 'base64-js'
 import {
     AudioMimeType,
@@ -68,7 +68,7 @@ export async function Decrypt(file, raw_filename, raw_ext) {
     }
 
     const info = GetMetaFromFile(raw_filename, musicMeta.common.title, musicMeta.common.artist)
-    if (handler.detect) reportKeyUsage(keyData, seed.Matrix128,
+    if (handler.detect) reportKeyUsage(keyData, seed.getMatrix128(),
         info.artist, info.title, musicMeta.common.album, raw_filename, raw_ext);
 
     let imgUrl = GetCoverFromFile(musicMeta);
@@ -126,7 +126,7 @@ async function queryKeyInfo(keyData, filename, format) {
             body: JSON.stringify({Format: format, Key: Base64Encode(keyData), Filename: filename, Type: 44}),
         });
         let data = await resp.json();
-        return QmcMaskCreate58(Base64Decode(data.Matrix44));
+        return new QmcMask(Base64Decode(data.Matrix44));
     } catch (e) {
         console.log(e);
     }

src/decrypt/qmcMask.ts

@@ -1,4 +1,4 @@
-import {BytesEquals, BytesHasPrefix, FLAC_HEADER, OGG_HEADER} from "@/decrypt/utils.ts";
+import {BytesHasPrefix, FLAC_HEADER, OGG_HEADER} from "@/decrypt/utils.ts";
 
 const QMOggPublicHeader1 = [
     0x4f, 0x67, 0x67, 0x53, 0x00, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xff, 0xff,
@@ -35,96 +35,65 @@ const QMCDefaultMaskMatrix = [
     0xf9, 0xbc, 0x00, 0x11];
 
 
-class QmcMask {
+const AllMapping: number[][] = [];
-    constructor(matrix, superA, superB) {
+const Mask128to44: number[] = [];
-        if (superA === undefined || superB === undefined) {
+
-            if (matrix.length === 44) {
+(function () {
-                this.Matrix44 = matrix
+    for (let i = 0; i < 128; i++) {
-                this.generateMask128from44()
+        let realIdx = (i * i + 27) % 256
-            } else {
+        if (realIdx in AllMapping) {
-                this.Matrix128 = matrix
+            AllMapping[realIdx].push(i)
-                this.generateMask44from128()
-            }
-            this.generateMask58from128()
         } else {
-            this.Matrix58 = matrix;
+            AllMapping[realIdx] = [i]
-            this.Super58A = superA;
-            this.Super58B = superB;
-            this.generateMask128from58();
-            this.generateMask44from128()
         }
     }
 
-    generateMask128from58() {
+    let idx44 = 0
-        if (this.Matrix58.length !== 56) throw "incorrect mask58 matrix length";
+    AllMapping.forEach(all128 => {
-
+        all128.forEach(_i128 => {
-        let matrix128 = [];
+            Mask128to44[_i128] = idx44
-        for (let rowIdx = 0; rowIdx < 8; rowIdx += 1) {
+        })
-            matrix128 = matrix128.concat(
+        idx44++
-                [this.Super58A],
+    })
-                this.Matrix58.slice(7 * rowIdx, 7 * rowIdx + 7),
+})();
-                [this.Super58B],
-                this.Matrix58.slice(56 - 7 - 7 * rowIdx, 56 - 7 * rowIdx).reverse()
-            );
-        }
-        this.Matrix128 = matrix128;
-    }
 
-    generateMask58from128() {
-        if (this.Matrix128.length !== 128) throw "incorrect mask128 length";
 
-        const superA = this.Matrix128[0], superB = this.Matrix128[8];
+export class QmcMask {
-        let matrix58 = [];
+    private readonly Matrix128: number[];
 
-        for (let rowIdx = 0; rowIdx < 8; rowIdx += 1) {
+    constructor(matrix: number[] | Uint8Array) {
-            let lenStart = 16 * rowIdx;
+        if (matrix instanceof Uint8Array) matrix = Array.from(matrix)
-            let lenRightStart = 120 - lenStart;
+        if (matrix.length === 44) {
-            if (this.Matrix128[lenStart] !== superA || this.Matrix128[lenStart + 8] !== superB) {
+            this.Matrix128 = this._generate128(matrix)
-                throw "decode mask-128 to mask-58 failed"
+        } else if (matrix.length === 128) {
-            }
+            this.Matrix128 = matrix
-            let rowLeft = this.Matrix128.slice(lenStart + 1, lenStart + 8);
-            let rowRight = this.Matrix128.slice(lenRightStart + 1, lenRightStart + 8).reverse();
-            if (BytesEquals(rowLeft, rowRight)) {
-                matrix58 = matrix58.concat(rowLeft);
         } else {
-                throw "decode mask-128 to mask-58 failed"
+            throw Error("invalid mask length")
         }
     }
-        this.Matrix58 = matrix58;
+
-        this.Super58A = superA;
+    getMatrix128() {
-        this.Super58B = superB;
+        return this.Matrix128
     }
 
-    generateMask44from128() {
+    getMatrix44(): number[] {
-        if (this.Matrix128.length !== 128) throw "incorrect mask128 matrix length";
+        const matrix44: number[] = []
-        let mapping = GetConvertMapping()
-        this.Matrix44 = []
         let idxI44 = 0
-        mapping.forEach(it256 => {
+        AllMapping.forEach(it256 => {
             let it256Len = it256.length
             for (let i = 1; i < it256Len; i++) {
                 if (this.Matrix128[it256[0]] !== this.Matrix128[it256[i]]) {
                     throw "decode mask-128 to mask-44 failed"
                 }
             }
-            this.Matrix44[idxI44] = this.Matrix128[it256[0]]
+            matrix44[idxI44] = this.Matrix128[it256[0]]
             idxI44++
         })
+        return matrix44
     }
 
-    generateMask128from44() {
+    Decrypt(data: Uint8Array) {
-        if (this.Matrix44.length !== 44) throw "incorrect mask length"
+        if (!this.Matrix128) throw Error("bad call sequence")
-        this.Matrix128 = []
-        let idx44 = 0
-        GetConvertMapping().forEach(it256 => {
-            it256.forEach(m => {
-                this.Matrix128[m] = this.Matrix44[idx44]
-            })
-            idx44++
-        })
-    }
-
-    Decrypt(data) {
         let dst = data.slice(0);
         let index = -1;
         let maskIdx = -1;
@@ -140,13 +109,25 @@ class QmcMask {
         }
         return dst;
     }
+
+    private _generate128(matrix44: number[]): number[] {
+        const matrix128: number[] = []
+        let idx44 = 0
+        AllMapping.forEach(it256 => {
+            it256.forEach(m => {
+                matrix128[m] = matrix44[idx44]
+            })
+            idx44++
+        })
+        return matrix128
+    }
 }
 
 export function QmcMaskGetDefault() {
     return new QmcMask(QMCDefaultMaskMatrix)
 }
 
-export function QmcMaskDetectMflac(data) {
+export function QmcMaskDetectMflac(data: Uint8Array) {
     let search_len = Math.min(0x8000, data.length), mask;
     for (let block_idx = 0; block_idx < search_len; block_idx += 128) {
         try {
@@ -160,9 +141,9 @@ export function QmcMaskDetectMflac(data) {
     return mask;
 }
 
-export function QmcMaskDetectMgg(data) {
+export function QmcMaskDetectMgg(data: Uint8Array) {
     if (data.length < 0x100) return
-    let matrixConfidence = {};
+    let matrixConfidence: { [key: number]: { [key: number]: number } } = {};
     for (let i = 0; i < 44; i++) matrixConfidence[i] = {};
 
     const page2 = data[0x54] ^ data[0xC] ^ QMOggPublicHeader1[0xC];
@@ -171,7 +152,7 @@ export function QmcMaskDetectMgg(data) {
 
     for (let idx128 = 0; idx128 < spHeader.length; idx128++) {
         if (spConf[idx128] === 0) continue;
-        let idx44 = GetMask44Index(idx128);
+        let idx44 = Mask128to44[idx128 % 128];
         let _m = data[idx128] ^ spHeader[idx128]
         let confidence = spConf[idx128];
         if (_m in matrixConfidence[idx44]) {
@@ -183,7 +164,7 @@ export function QmcMaskDetectMgg(data) {
     let matrix = [];
     try {
         for (let i = 0; i < 44; i++)
-            matrix[i] = getMaskConfidenceResult(matrixConfidence[i]);
+            matrix[i] = calcMaskFromConfidence(matrixConfidence[i]);
     } catch (e) {
         return;
     }
@@ -191,82 +172,34 @@ export function QmcMaskDetectMgg(data) {
     if (!BytesHasPrefix(mask.Decrypt(data.slice(0, OGG_HEADER.length)), OGG_HEADER)) {
         return;
     }
-
     return mask;
 }
 
-export function QmcMaskCreate128(mask128) {
-    return new QmcMask(mask128)
-}
-
-export function QmcMaskCreate58(matrix, superA, superB) {
-    return new QmcMask(matrix, superA, superB)
-}
-
-export function QmcMaskCreate44(mask44) {
-    return new QmcMask(mask44)
-}
 
-/**
+function calcMaskFromConfidence(confidence: { [key: number]: number }) {
- * @param confidence {{}}
+    console.log(confidence)
- * @returns {number}
+    const count = Object.keys(confidence).length
- */
+    if (count === 0) throw "can not match at least one key";
-function getMaskConfidenceResult(confidence) {
+    if (count > 1) console.warn("There are 2 potential value for the mask!")
-    if (confidence.length === 0) throw "can not match at least one key";
+    let result = ""
-    if (confidence.length > 1) console.warn("There are 2 potential value for the mask!")
+    let conf = 0
-    let result, conf = 0;
     for (let idx in confidence) {
         if (confidence[idx] > conf) {
             result = idx;
             conf = confidence[idx];
         }
     }
-    return parseInt(result)
+    return Number(result)
-}
-
-/**
- * @return {number}
- */
-
-
-const allMapping = [];
-const mask128to44 = [];
-
-(function () {
-    for (let i = 0; i < 128; i++) {
-        let realIdx = (i * i + 27) % 256
-        if (realIdx in allMapping) {
-            allMapping[realIdx].push(i)
-        } else {
-            allMapping[realIdx] = [i]
-        }
-    }
-
-    let idx44 = 0
-    allMapping.forEach(all128 => {
-        all128.forEach(_i128 => {
-            mask128to44[_i128] = idx44
-        })
-        idx44++
-    })
-})();
-
-function GetConvertMapping() {
-    return allMapping;
-}
-
-function GetMask44Index(idx128) {
-    return mask128to44[idx128 % 128]
 }
 
-function QmcGenerateOggHeader(page2) {
+function QmcGenerateOggHeader(page2: number) {
     let spec = [page2, 0xFF]
     for (let i = 2; i < page2; i++) spec.push(0xFF)
     spec.push(0xFF)
     return QMOggPublicHeader1.concat(spec, QMOggPublicHeader2)
 }
 
-function QmcGenerateOggConf(page2) {
+function QmcGenerateOggConf(page2: number) {
     let specConf = [6, 0]
     for (let i = 2; i < page2; i++) specConf.push(4)
     specConf.push(0)