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forked from um/web
web/src/decrypt/kgm.ts

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import {
AudioMimeType,
BytesHasPrefix,
GetArrayBuffer,
GetCoverFromFile,
GetMetaFromFile,
SniffAudioExt
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} from "@/decrypt/utils";
import {parseBlob as metaParseBlob} from "music-metadata-browser";
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import {DecryptResult} from "@/decrypt/entity";
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import config from "@/../package.json"
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const VprHeader = [
0x05, 0x28, 0xBC, 0x96, 0xE9, 0xE4, 0x5A, 0x43,
0x91, 0xAA, 0xBD, 0xD0, 0x7A, 0xF5, 0x36, 0x31]
const KgmHeader = [
0x7C, 0xD5, 0x32, 0xEB, 0x86, 0x02, 0x7F, 0x4B,
0xA8, 0xAF, 0xA6, 0x8E, 0x0F, 0xFF, 0x99, 0x14]
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const VprMaskDiff = [
0x25, 0xDF, 0xE8, 0xA6, 0x75, 0x1E, 0x75, 0x0E,
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0x2F, 0x80, 0xF3, 0x2D, 0xB8, 0xB6, 0xE3, 0x11,
0x00]
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export async function Decrypt(file: File, raw_filename: string, raw_ext: string): Promise<DecryptResult> {
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const oriData = new Uint8Array(await GetArrayBuffer(file));
if (raw_ext === "vpr") {
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if (!BytesHasPrefix(oriData, VprHeader)) throw Error("Not a valid vpr file!")
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} else {
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if (!BytesHasPrefix(oriData, KgmHeader)) throw Error("Not a valid kgm(a) file!")
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}
let bHeaderLen = new DataView(oriData.slice(0x10, 0x14).buffer)
let headerLen = bHeaderLen.getUint32(0, true)
let audioData = oriData.slice(headerLen)
let dataLen = audioData.length
if (audioData.byteLength > 1 << 26) {
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throw Error("文件过大,请使用 <a target='_blank' href='https://github.com/unlock-music/cli'>CLI版本</a> 进行解锁")
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}
let key1 = new Uint8Array(17)
key1.set(oriData.slice(0x1c, 0x2c), 0)
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if (MaskV2.length === 0) {
if (!await LoadMaskV2()) throw Error("加载Kgm/Vpr Mask数据失败")
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}
for (let i = 0; i < dataLen; i++) {
let med8 = key1[i % 17] ^ audioData[i]
med8 ^= (med8 & 0xf) << 4
let msk8 = GetMask(i)
msk8 ^= (msk8 & 0xf) << 4
audioData[i] = med8 ^ msk8
}
if (raw_ext === "vpr") {
for (let i = 0; i < dataLen; i++) audioData[i] ^= VprMaskDiff[i % 17]
}
const ext = SniffAudioExt(audioData);
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const mime = AudioMimeType[ext];
let musicBlob = new Blob([audioData], {type: mime});
const musicMeta = await metaParseBlob(musicBlob);
const {title, artist} = GetMetaFromFile(raw_filename, musicMeta.common.title, musicMeta.common.artist)
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return {
album: musicMeta.common.album,
picture: GetCoverFromFile(musicMeta),
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file: URL.createObjectURL(musicBlob),
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blob: musicBlob,
ext,
mime,
title,
artist
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}
}
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function GetMask(pos: number) {
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return MaskV2PreDef[pos % 272] ^ MaskV2[pos >> 4]
}
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let MaskV2: Uint8Array = new Uint8Array(0);
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async function LoadMaskV2(): Promise<boolean> {
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let mask_url = `https://cdn.jsdelivr.net/gh/unlock-music/unlock-music@${config.version}/public/static/kgm.mask`
if (["http:", "https:"].some(v => v == self.location.protocol)) {
if (!!self.document) {// using Web Worker
mask_url = "./static/kgm.mask"
} else {// using Main thread
mask_url = "../static/kgm.mask"
}
}
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try {
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const resp = await fetch(mask_url, {method: "GET"})
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MaskV2 = new Uint8Array(await resp.arrayBuffer());
return true
} catch (e) {
console.error(e)
return false
}
}
const MaskV2PreDef = [
0xB8, 0xD5, 0x3D, 0xB2, 0xE9, 0xAF, 0x78, 0x8C, 0x83, 0x33, 0x71, 0x51, 0x76, 0xA0, 0xCD, 0x37,
0x2F, 0x3E, 0x35, 0x8D, 0xA9, 0xBE, 0x98, 0xB7, 0xE7, 0x8C, 0x22, 0xCE, 0x5A, 0x61, 0xDF, 0x68,
0x69, 0x89, 0xFE, 0xA5, 0xB6, 0xDE, 0xA9, 0x77, 0xFC, 0xC8, 0xBD, 0xBD, 0xE5, 0x6D, 0x3E, 0x5A,
0x36, 0xEF, 0x69, 0x4E, 0xBE, 0xE1, 0xE9, 0x66, 0x1C, 0xF3, 0xD9, 0x02, 0xB6, 0xF2, 0x12, 0x9B,
0x44, 0xD0, 0x6F, 0xB9, 0x35, 0x89, 0xB6, 0x46, 0x6D, 0x73, 0x82, 0x06, 0x69, 0xC1, 0xED, 0xD7,
0x85, 0xC2, 0x30, 0xDF, 0xA2, 0x62, 0xBE, 0x79, 0x2D, 0x62, 0x62, 0x3D, 0x0D, 0x7E, 0xBE, 0x48,
0x89, 0x23, 0x02, 0xA0, 0xE4, 0xD5, 0x75, 0x51, 0x32, 0x02, 0x53, 0xFD, 0x16, 0x3A, 0x21, 0x3B,
0x16, 0x0F, 0xC3, 0xB2, 0xBB, 0xB3, 0xE2, 0xBA, 0x3A, 0x3D, 0x13, 0xEC, 0xF6, 0x01, 0x45, 0x84,
0xA5, 0x70, 0x0F, 0x93, 0x49, 0x0C, 0x64, 0xCD, 0x31, 0xD5, 0xCC, 0x4C, 0x07, 0x01, 0x9E, 0x00,
0x1A, 0x23, 0x90, 0xBF, 0x88, 0x1E, 0x3B, 0xAB, 0xA6, 0x3E, 0xC4, 0x73, 0x47, 0x10, 0x7E, 0x3B,
0x5E, 0xBC, 0xE3, 0x00, 0x84, 0xFF, 0x09, 0xD4, 0xE0, 0x89, 0x0F, 0x5B, 0x58, 0x70, 0x4F, 0xFB,
0x65, 0xD8, 0x5C, 0x53, 0x1B, 0xD3, 0xC8, 0xC6, 0xBF, 0xEF, 0x98, 0xB0, 0x50, 0x4F, 0x0F, 0xEA,
0xE5, 0x83, 0x58, 0x8C, 0x28, 0x2C, 0x84, 0x67, 0xCD, 0xD0, 0x9E, 0x47, 0xDB, 0x27, 0x50, 0xCA,
0xF4, 0x63, 0x63, 0xE8, 0x97, 0x7F, 0x1B, 0x4B, 0x0C, 0xC2, 0xC1, 0x21, 0x4C, 0xCC, 0x58, 0xF5,
0x94, 0x52, 0xA3, 0xF3, 0xD3, 0xE0, 0x68, 0xF4, 0x00, 0x23, 0xF3, 0x5E, 0x0A, 0x7B, 0x93, 0xDD,
0xAB, 0x12, 0xB2, 0x13, 0xE8, 0x84, 0xD7, 0xA7, 0x9F, 0x0F, 0x32, 0x4C, 0x55, 0x1D, 0x04, 0x36,
0x52, 0xDC, 0x03, 0xF3, 0xF9, 0x4E, 0x42, 0xE9, 0x3D, 0x61, 0xEF, 0x7C, 0xB6, 0xB3, 0x93, 0x50,
]