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qqmusicunlock/src/decrypt/qmc.ts

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import { QmcMapCipher, QmcRC4Cipher, QmcStaticCipher, QmcStreamCipher } from './qmc_cipher';
import { AudioMimeType, GetArrayBuffer, SniffAudioExt } from '@/decrypt/utils';
import { DecryptResult } from '@/decrypt/entity';
import { QmcDeriveKey } from '@/decrypt/qmc_key';
import { DecryptQMCWasm } from '@/decrypt/qmc_wasm';
import { extractQQMusicMeta } from '@/utils/qm_meta';
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interface Handler {
ext: string;
version: number;
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}
export const HandlerMap: { [key: string]: Handler } = {
mgg: { ext: 'ogg', version: 2 },
mgg0: { ext: 'ogg', version: 2 },
mggl: { ext: 'ogg', version: 2 },
mgg1: { ext: 'ogg', version: 2 },
mflac: { ext: 'flac', version: 2 },
mflac0: { ext: 'flac', version: 2 },
// qmcflac / qmcogg:
// 有可能是 v2 加密但混用同一个后缀名。
qmcflac: { ext: 'flac', version: 2 },
qmcogg: { ext: 'ogg', version: 2 },
qmc0: { ext: 'mp3', version: 1 },
qmc2: { ext: 'ogg', version: 1 },
qmc3: { ext: 'mp3', version: 1 },
bkcmp3: { ext: 'mp3', version: 1 },
bkcflac: { ext: 'flac', version: 1 },
tkm: { ext: 'm4a', version: 1 },
'666c6163': { ext: 'flac', version: 1 },
'6d7033': { ext: 'mp3', version: 1 },
'6f6767': { ext: 'ogg', version: 1 },
'6d3461': { ext: 'm4a', version: 1 },
'776176': { ext: 'wav', version: 1 },
};
export async function Decrypt(file: Blob, raw_filename: string, raw_ext: string): Promise<DecryptResult> {
if (!(raw_ext in HandlerMap)) throw `Qmc cannot handle type: ${raw_ext}`;
const handler = HandlerMap[raw_ext];
let { version } = handler;
const fileBuffer = await GetArrayBuffer(file);
let musicDecoded: Uint8Array | undefined;
let musicID: number | string | undefined;
if (version === 2 && globalThis.WebAssembly) {
console.log('qmc: using wasm decoder');
const v2Decrypted = await DecryptQMCWasm(fileBuffer);
// 若 v2 检测失败,降级到 v1 再尝试一次
if (v2Decrypted.success) {
musicDecoded = v2Decrypted.data;
musicID = v2Decrypted.songId;
} else {
console.warn('qmc2-wasm failed with error %s', v2Decrypted.error || '(no error)');
}
}
if (!musicDecoded) {
// may throw error
console.log('qmc: using js decoder');
const d = new QmcDecoder(new Uint8Array(fileBuffer));
musicDecoded = d.decrypt();
musicID = d.songID;
}
const ext = SniffAudioExt(musicDecoded, handler.ext);
const mime = AudioMimeType[ext];
const { album, artist, imgUrl, blob, title } = await extractQQMusicMeta(
new Blob([musicDecoded], { type: mime }),
raw_filename,
ext,
musicID,
);
return {
title: title,
artist: artist,
ext: ext,
album: album,
picture: imgUrl,
file: URL.createObjectURL(blob),
blob: blob,
mime: mime,
};
}
export class QmcDecoder {
private static readonly BYTE_COMMA = ','.charCodeAt(0);
private readonly file: Uint8Array;
private readonly size: number;
private decoded: boolean = false;
private audioSize?: number;
private cipher?: QmcStreamCipher;
public constructor(file: Uint8Array) {
this.file = file;
this.size = file.length;
this.searchKey();
}
private _songID?: number;
public get songID() {
return this._songID;
}
public decrypt(): Uint8Array {
if (!this.cipher) {
throw new Error('no cipher found');
}
if (!this.audioSize || this.audioSize <= 0) {
throw new Error('invalid audio size');
}
const audioBuf = this.file.subarray(0, this.audioSize);
if (!this.decoded) {
this.cipher.decrypt(audioBuf, 0);
this.decoded = true;
}
return audioBuf;
}
private searchKey() {
const last4Byte = this.file.slice(-4);
const textEnc = new TextDecoder();
if (textEnc.decode(last4Byte) === 'QTag') {
const sizeBuf = this.file.slice(-8, -4);
const sizeView = new DataView(sizeBuf.buffer, sizeBuf.byteOffset);
const keySize = sizeView.getUint32(0, false);
this.audioSize = this.size - keySize - 8;
const rawKey = this.file.subarray(this.audioSize, this.size - 8);
const keyEnd = rawKey.findIndex((v) => v == QmcDecoder.BYTE_COMMA);
if (keyEnd < 0) {
throw new Error('invalid key: search raw key failed');
}
this.setCipher(rawKey.subarray(0, keyEnd));
const idBuf = rawKey.subarray(keyEnd + 1);
const idEnd = idBuf.findIndex((v) => v == QmcDecoder.BYTE_COMMA);
if (keyEnd < 0) {
throw new Error('invalid key: search song id failed');
}
this._songID = parseInt(textEnc.decode(idBuf.subarray(0, idEnd)), 10);
} else {
const sizeView = new DataView(last4Byte.buffer, last4Byte.byteOffset);
const keySize = sizeView.getUint32(0, true);
if (keySize < 0x300) {
this.audioSize = this.size - keySize - 4;
const rawKey = this.file.subarray(this.audioSize, this.size - 4);
this.setCipher(rawKey);
} else {
this.audioSize = this.size;
this.cipher = new QmcStaticCipher();
}
}
}
private setCipher(keyRaw: Uint8Array) {
const keyDec = QmcDeriveKey(keyRaw);
if (keyDec.length > 300) {
this.cipher = new QmcRC4Cipher(keyDec);
} else {
this.cipher = new QmcMapCipher(keyDec);
}
}
}