1
0
forked from um/web
web/src/decrypt/kgm.ts
2022-11-22 06:40:02 +08:00

78 lines
2.6 KiB
TypeScript

import {
AudioMimeType,
BytesHasPrefix,
GetArrayBuffer,
GetCoverFromFile,
GetMetaFromFile,
SniffAudioExt,
} from '@/decrypt/utils';
import { parseBlob as metaParseBlob } from 'music-metadata-browser';
import { DecryptResult } from '@/decrypt/entity';
import { DecryptKgmWasm } from '@/decrypt/kgm_wasm';
import { decryptKgmByteAtOffsetV2, decryptVprByteAtOffset } from '@jixun/kugou-crypto/dist/utils/decryptionHelper';
//prettier-ignore
const VprHeader = [
0x05, 0x28, 0xBC, 0x96, 0xE9, 0xE4, 0x5A, 0x43,
0x91, 0xAA, 0xBD, 0xD0, 0x7A, 0xF5, 0x36, 0x31
]
//prettier-ignore
const KgmHeader = [
0x7C, 0xD5, 0x32, 0xEB, 0x86, 0x02, 0x7F, 0x4B,
0xA8, 0xAF, 0xA6, 0x8E, 0x0F, 0xFF, 0x99, 0x14
]
export async function Decrypt(file: File, raw_filename: string, raw_ext: string): Promise<DecryptResult> {
const oriData = await GetArrayBuffer(file);
if (raw_ext === 'vpr') {
if (!BytesHasPrefix(new Uint8Array(oriData), VprHeader)) throw Error('Not a valid vpr file!');
} else {
if (!BytesHasPrefix(new Uint8Array(oriData), KgmHeader)) throw Error('Not a valid kgm(a) file!');
}
let musicDecoded: Uint8Array | undefined;
if (globalThis.WebAssembly) {
console.log('kgm: using wasm decoder');
const kgmDecrypted = await DecryptKgmWasm(oriData, raw_ext);
if (kgmDecrypted.success) {
musicDecoded = kgmDecrypted.data;
console.log('kgm wasm decoder suceeded');
} else {
console.warn('KgmWasm failed with error %s', kgmDecrypted.error || '(unknown error)');
}
}
if (!musicDecoded) {
musicDecoded = new Uint8Array(oriData);
let bHeaderLen = new DataView(musicDecoded.slice(0x10, 0x14).buffer);
let headerLen = bHeaderLen.getUint32(0, true);
let key1 = Array.from(musicDecoded.slice(0x1c, 0x2c));
key1.push(0);
musicDecoded = musicDecoded.slice(headerLen);
let dataLen = musicDecoded.length;
const decryptByte = raw_ext === 'vpr' ? decryptVprByteAtOffset : decryptKgmByteAtOffsetV2;
for (let i = 0; i < dataLen; i++) {
musicDecoded[i] = decryptByte(musicDecoded[i], key1, i);
}
}
const ext = SniffAudioExt(musicDecoded);
const mime = AudioMimeType[ext];
let musicBlob = new Blob([musicDecoded], { type: mime });
const musicMeta = await metaParseBlob(musicBlob);
const { title, artist } = GetMetaFromFile(raw_filename, musicMeta.common.title, String(musicMeta.common.artists || musicMeta.common.artist || ""));
return {
album: musicMeta.common.album,
picture: GetCoverFromFile(musicMeta),
file: URL.createObjectURL(musicBlob),
blob: musicBlob,
ext,
mime,
title,
artist,
};
}