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AESDecryption()

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This commit is contained in:
ReznoRMichael 2021-01-23 01:19:19 +01:00
parent 4ec77f8c3a
commit 49d275c1bc
1 changed files with 19 additions and 4 deletions
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23
js/LoadSaveFile.js
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@ -3,6 +3,12 @@ const CSHARP_HEADER = [0, 1, 0, 0, 0, 255, 255, 255, 255, 1, 0, 0, 0, 0, 0, 0, 0
const BASE64_ARRAY = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=".split("").map(c => c.charCodeAt(0));
const BASE64_DECODE_TABLE = new Map(BASE64_ARRAY.map((ord, i) => [ord, i]));
const AES_KEY = new TextEncoder().encode('UKu52ePUBwetZ9wNX88o54dnfKRu0T1l'); // encodes to Uint8Array
const ECB_STREAM_CIPHER = new aesjs.ModeOfOperation.ecb(AES_KEY); // create a new AES stream cipher object
console.log(`AES_KEY: ${AES_KEY}`);
console.log(`ECB_STREAM_CIPHER: ${ECB_STREAM_CIPHER}`);
function ShowFile(input) {
let inputFileObject = input.files[0];
@ -28,7 +34,6 @@ function LoadSaveFile(input) {
// 2. Decode file
// AES decryption (ECB) removes pkcs7 padding (ArrayBuffer)
// Convert ArrayBuffer to string/text TextDecoder().decode(ArrayBuffer)
// 3. Convert file to JSON string (optional?)
@ -55,9 +60,12 @@ function FileObjectToArrayBuffer() {
// base64 Decoding (ArrayBuffer)
inputArrayBuffer = Base64Decode(inputArrayBuffer);
alert(`File: ${inputArrayBuffer}`);
// AES decryption (ECB) removes pkcs7 padding (ArrayBuffer)
inputArrayBuffer = AESDecryption(inputArrayBuffer);
alert(`Array Buffer: ${inputArrayBuffer}`);
} catch (error) {
alert(`The file cannot be read. Error: ${error}`);
alert(`The file cannot be decoded. Error: ${error}`);
}
}
@ -80,7 +88,7 @@ function RemoveCSharpHeader(buffer) {
return fixedArrayBuffer;
}
// From bloodorca https://github.com/bloodorca/hollow based on KayDeeTee https://github.com/KayDeeTee/Hollow-Knight-SaveManager
// Thanks to KayDeeTee https://github.com/KayDeeTee/Hollow-Knight-SaveManager and bloodorca https://github.com/bloodorca/hollow (base64.js)
function Base64Decode(buffer) {
buffer = new Uint8Array(buffer).slice();
buffer = buffer.map(v => BASE64_DECODE_TABLE.get(v))
@ -105,3 +113,10 @@ function Base64Decode(buffer) {
}
return output;
}
// Thanks to KayDeeTee https://github.com/KayDeeTee/Hollow-Knight-SaveManager and bloodorca https://github.com/bloodorca/hollow (functions.js)
// Decrypt the Uint8Array Buffer using aesjs and a predefined AES key + remove pkcs7 padding
function AESDecryption(buffer) {
let output = ECB_STREAM_CIPHER.decrypt(buffer);
return output.subarray(0, -output[output.length - 1]);
}