130 lines
4.0 KiB
JavaScript
130 lines
4.0 KiB
JavaScript
const musicMetadata = require("music-metadata-browser");
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const util = require("./util");
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export {Decrypt}
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const FLAC_HEADER = [0x66, 0x4C, 0x61, 0x43, 0x00];
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async function Decrypt(file, raw_filename, raw_ext) {
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// 获取扩展名
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if (raw_ext !== "mflac") return {
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status: false,
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message: "File type is incorrect!",
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};
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// 读取文件
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const fileBuffer = await util.GetArrayBuffer(file);
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const audioData = new Uint8Array(fileBuffer.slice(0, -0x170));
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const audioDataLen = audioData.length;
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// 转换数据
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const seed = new Mask();
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if (!seed.DetectMask(audioData)) return {
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status: false,
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message: "此音乐无法解锁，目前mflac格式不提供完整支持",
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};
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for (let cur = 0; cur < audioDataLen; ++cur) {
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audioData[cur] ^= seed.NextMask();
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}
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// 导出
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const musicData = new Blob([audioData], {type: "audio/flac"});
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// 读取Meta
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let tag = await musicMetadata.parseBlob(musicData);
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const info = util.GetFileInfo(tag.common.artist, tag.common.title, raw_filename);
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reportKeyInfo(new Uint8Array(fileBuffer.slice(-0x170)), seed.mask128,
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info.artist, info.title, tag.common.album, raw_filename);
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// 返回
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return {
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status: true,
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title: info.title,
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artist: info.artist,
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ext: 'flac',
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album: tag.common.album,
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picture: util.GetCoverURL(tag),
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file: URL.createObjectURL(musicData),
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mime: "audio/flac"
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}
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}
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class Mask {
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constructor() {
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this.index = -1;
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this.mask_index = -1;
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this.mask128 = new Uint8Array(128);
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this.mask58_martix = new Uint8Array(56);
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this.mask58_super1 = 0x00;
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this.mask58_super2 = 0x00;
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}
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DetectMask(data) {
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let search_len = Math.min(0x8000, data.length), mask;
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for (let block_idx = 0; block_idx < search_len; block_idx += 128) {
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mask = data.slice(block_idx, block_idx + 128);
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const mask58 = this.Convert128to58(mask);
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if (mask58 === undefined) continue;
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if (!FLAC_HEADER.every((val, idx) => {
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return val === mask[idx] ^ data[idx];
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})) continue;
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this.mask128 = mask;
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this.mask58_martix = mask58.matrix;
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this.mask58_super1 = mask58.super_8_1;
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this.mask58_super2 = mask58.super_8_2;
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return true;
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}
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return false;
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}
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Convert128to58(mask128) {
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const super_8_1 = mask128[0], super_8_2 = mask128[8];
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let matrix = [];
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for (let row_idx = 0; row_idx < 8; row_idx++) {
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const len_start = 16 * row_idx;
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const len_right_start = 120 - len_start;//16*(8-row_idx-1)+8
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if (mask128[len_start] !== super_8_1 || mask128[len_start + 8] !== super_8_2) {
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return
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}
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const row_left = mask128.slice(len_start + 1, len_start + 8);
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const row_right = mask128.slice(len_right_start + 1, len_right_start + 8).reverse();
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if (row_left.every((val, idx) => {
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return row_right[idx] === val
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})) {
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matrix.push(row_left);
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} else {
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return
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}
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}
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return {matrix, super_8_1, super_8_2}
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}
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NextMask() {
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this.index++;
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this.mask_index++;
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if (this.index === 0x8000 || (this.index > 0x8000 && (this.index + 1) % 0x8000 === 0)) {
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this.index++;
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this.mask_index++;
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}
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if (this.mask_index >= 128) {
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this.mask_index -= 128;
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}
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return this.mask128[this.mask_index]
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}
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}
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function reportKeyInfo(keyData, maskData, artist, title, album, filename) {
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fetch("https://stats.ixarea.com/collect/mflac/mask", {
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method: "POST",
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headers: {"Content-Type": "application/json"},
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body: JSON.stringify({
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Mask: Array.from(maskData), Key: Array.from(keyData),
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Artist: artist, Title: title, Album: album, Filename: filename
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}),
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}).then().catch()
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}
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