75 lines
2.0 KiB
TypeScript
75 lines
2.0 KiB
TypeScript
import KgmCryptoModule from '@/KgmWasm/KgmWasmBundle';
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import { MergeUint8Array } from '@/utils/MergeUint8Array';
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// 每次处理 2M 的数据
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const DECRYPTION_BUF_SIZE = 2 * 1024 * 1024;
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export interface KGMDecryptionResult {
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success: boolean;
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data: Uint8Array;
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error: string;
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}
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/**
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* 解密一个 KGM 加密的文件。
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*
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* 如果检测并解密成功，返回解密后的 Uint8Array 数据。
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* @param {ArrayBuffer} kgmBlob 读入的文件 Blob
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*/
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export async function DecryptKgmWasm(
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kgmBlob: ArrayBuffer,
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ext: string
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): Promise<KGMDecryptionResult> {
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const result: KGMDecryptionResult = {
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success: false,
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data: new Uint8Array(),
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error: '',
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};
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// 初始化模组
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let KgmCrypto: any;
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try {
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KgmCrypto = await KgmCryptoModule();
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} catch (err: any) {
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result.error = err?.message || 'wasm 加载失败';
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return result;
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}
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if (!KgmCrypto) {
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result.error = 'wasm 加载失败';
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return result;
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}
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// 申请内存块，并文件末端数据到 WASM 的内存堆
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let kgmBuf = new Uint8Array(kgmBlob);
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const pQmcBuf = KgmCrypto._malloc(DECRYPTION_BUF_SIZE);
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KgmCrypto.writeArrayToMemory(kgmBuf.slice(0, DECRYPTION_BUF_SIZE), pQmcBuf);
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// 进行解密初始化
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const headerSize = KgmCrypto.preDec(pQmcBuf, DECRYPTION_BUF_SIZE, ext);
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console.log(headerSize);
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kgmBuf = kgmBuf.slice(headerSize);
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const decryptedParts = [];
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let offset = 0;
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let bytesToDecrypt = kgmBuf.length;
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while (bytesToDecrypt > 0) {
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const blockSize = Math.min(bytesToDecrypt, DECRYPTION_BUF_SIZE);
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// 解密一些片段
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const blockData = new Uint8Array(kgmBuf.slice(offset, offset + blockSize));
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KgmCrypto.writeArrayToMemory(blockData, pQmcBuf);
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KgmCrypto.decBlob(pQmcBuf, blockSize, offset);
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decryptedParts.push(KgmCrypto.HEAPU8.slice(pQmcBuf, pQmcBuf + blockSize));
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offset += blockSize;
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bytesToDecrypt -= blockSize;
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}
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KgmCrypto._free(pQmcBuf);
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result.data = MergeUint8Array(decryptedParts);
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result.success = true;
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return result;
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}
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