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

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import {
AudioMimeType,
BytesHasPrefix,
GetArrayBuffer,
GetCoverFromFile,
GetMetaFromFile,
SniffAudioExt,
} from '@/decrypt/utils';
import { parseBlob as metaParseBlob } from 'music-metadata-browser';
import { DecryptResult } from '@/decrypt/entity';
import config from '@/../package.json';
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//prettier-ignore
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const VprHeader = [
0x05, 0x28, 0xBC, 0x96, 0xE9, 0xE4, 0x5A, 0x43,
0x91, 0xAA, 0xBD, 0xD0, 0x7A, 0xF5, 0x36, 0x31
]
//prettier-ignore
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const KgmHeader = [
0x7C, 0xD5, 0x32, 0xEB, 0x86, 0x02, 0x7F, 0x4B,
0xA8, 0xAF, 0xA6, 0x8E, 0x0F, 0xFF, 0x99, 0x14
]
//prettier-ignore
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const VprMaskDiff = [
0x25, 0xDF, 0xE8, 0xA6, 0x75, 0x1E, 0x75, 0x0E,
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> {
const oriData = new Uint8Array(await GetArrayBuffer(file));
if (raw_ext === 'vpr') {
if (!BytesHasPrefix(oriData, VprHeader)) throw Error('Not a valid vpr file!');
} else {
if (!BytesHasPrefix(oriData, KgmHeader)) throw Error('Not a valid kgm(a) file!');
}
let bHeaderLen = new DataView(oriData.slice(0x10, 0x14).buffer);
let headerLen = bHeaderLen.getUint32(0, true);
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let audioData = oriData.slice(headerLen);
let dataLen = audioData.length;
if (audioData.byteLength > 1 << 26) {
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);
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;
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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];
}
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const ext = SniffAudioExt(audioData);
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);
return {
album: musicMeta.common.album,
picture: GetCoverFromFile(musicMeta),
file: URL.createObjectURL(musicBlob),
blob: musicBlob,
ext,
mime,
title,
artist,
};
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}
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function GetMask(pos: number) {
return MaskV2PreDef[pos % 272] ^ MaskV2[pos >> 4];
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}
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let MaskV2: Uint8Array = new Uint8Array(0);
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async function LoadMaskV2(): Promise<boolean> {
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 {
const resp = await fetch(mask_url, { method: 'GET' });
MaskV2 = new Uint8Array(await resp.arrayBuffer());
return true;
} catch (e) {
console.error(e);
return false;
}
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}
//prettier-ignore
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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,
];