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// as seen in /usr/lib/libzc.so / SetupKeys
const MASTER_KEY = new Uint8Array([
0x13, 0x27, 0x3f, 0x42,
0xa5, 0xb6, 0x79, 0xe8,
0x20, 0x31, 0xc4, 0xf5,
0x16, 0x17, 0x88, 0x2f,
0x43, 0xa4, 0x55, 0x69,
0x77, 0xb8, 0xe2, 0x83,
0x04, 0x05, 0x60, 0x70,
0x80, 0x02, 0x03, 0x04,
0x50, 0x6a, 0x7c, 0x8a,
0x02, 0x30, 0x40, 0x51,
0x6a, 0x7d, 0x8d, 0x22,
0x33, 0x44, 0x59, 0x66,
0x71, 0x08, 0x02, 0x03,
0x43, 0x05, 0x67, 0x7a,
0x8f]);
function hex(byteArray) {
return Array.prototype.map.call(byteArray, function (byte) {
return ('0' + (byte & 0xFF).toString(16)).slice(-2);
}).join('');
}
// ported from EVP_BytesToKey
// https://github.com/openssl/openssl/blob/c04e78f0c69201226430fed14c291c281da47f2d/crypto/evp/evp_key.c#L78
function deriveKeyAndIV(password, iterations = 10) {
var keyLen = 16;
var ivLen = 16;
var addmd = 0;
var key = new Uint8Array(keyLen);
var iv = new Uint8Array(ivLen);
var tmp = new Uint8Array();
var i, key_i = 0, iv_i = 0;
for (; keyLen > 0 || ivLen > 0;) {
if (addmd++) {
block = new Uint8Array([...tmp, ...password]);
} else {
block = password;
}
tmp = new Uint8Array(sha1.array(block));
for (i = 1; i < iterations; i++) {
tmp = sha1.array(tmp);
}
i = 0;
while (keyLen && i != tmp.length) {
key[key_i++] = tmp[i];
keyLen--;
i++;
}
while (ivLen != 0 && i != tmp.length) {
iv[iv_i++] = tmp[i];
ivLen--;
i++;
}
}
return { key: key, iv: iv };
}
function processFileInput(e) {
const fileName = e.target.fileName;
const serial = document.getElementById('serial-input').value;
let main_key = null;
if (serial.length > 0) {
// local decryption, use master key + serial
main_key = new Uint8Array([...MASTER_KEY, ...new TextEncoder("utf-8").encode(serial)]);
} else {
// global decryption, use master key only
main_key = MASTER_KEY;
}
// derive key and iv with our EVP_BytesToKey port
const derived = deriveKeyAndIV(main_key);
// encrypted file contents
const ciphertext = e.target.result;
// import the raw key
window.crypto.subtle.importKey("raw", derived.key, "AES-CTR", true, ["encrypt", "decrypt"]).then(function (key) {
// decrypt using aes-128-ctr
window.crypto.subtle.decrypt({ name: "AES-CTR", counter: derived.iv, length: 128 }, key, ciphertext).then(function (cleartext) {
var blob = new Blob([cleartext], { type: "application/octet-stream" });
const link = document.createElement('a');
link.href = window.URL.createObjectURL(blob);
link.download = fileName + '.dec';
link.click();
});
});
}
document.addEventListener("DOMContentLoaded", function () {
// handle file uploads
let fileInput = document.getElementById('file-input')
fileInput.onchange = () => {
const reader = new FileReader()
reader.onload = processFileInput;
for (let file of fileInput.files) {
// https://stackoverflow.com/questions/24245105/how-to-get-the-filename-from-the-javascript-filereader
reader.fileName = file.name;
reader.readAsArrayBuffer(file);
}
};
});
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