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Import JWK signature from file and verify information Web Cryptography API

Fail to verify signature using Web Cryptography API and RSASSA-PKCS1-v1_5 algorithm keys.
Save the signature generated with the sign function in postgreSQL as a string:
window.crypto.subtle
.sign("RSASSA-PKCS1-v1_5", key, this.str2ab(hash))
.then(sigNature => {
const sig = this.ab2hex(sigNature); //save sig -> postgreSQL
});
I try to verify using signature that I get fron postgreSQL:
window.crypto.subtle
.verify(
"RSASSA-PKCS1-v1_5",
key,
this.str2ab(_signature), //from pSQL
this.str2ab(_hash) //from pSQL
)
.then(isVerified => {
console.log(isVerified);
});
Utils:
* String -> ArrayBuffer function:
private str2ab(str) {
var buf = new ArrayBuffer(str.length * 2); // 2 bytes for each char
var bufView = new Uint16Array(buf);
for (var i = 0, strLen = str.length; i < strLen; i++) {
bufView[i] = str.charCodeAt(i);
}
return buf;
}
ArrayBuffer -> HEX function:
private ab2hex(buffer) {
// buffer is an ArrayBuffer
return Array.prototype.map
.call(new Uint8Array(buffer), x => ("00" + x.toString(16)).slice(-2))
.join("");
}
The problem is that I always get "false" as response from verify function even if I used correct key pair to sign and verify

How to Directly Instantiate WebAssembly Module in JavaScript

The examples I've seen show essentially this:
fetch('simple.wasm').then(response =>
response.arrayBuffer()
).then(bytes =>
WebAssembly.instantiate(bytes, {})
).then(result =>
result.instance.exports...
)
But I would like to do it without making that extra HTTP request. Wondering if the only way is this (or some variation of it, which would be helpful to know):
var binary = '...mywasmbinary...'
var buffer = new ArrayBuffer(binary.length)
var view = new DataView(buffer)
for (var i = 0, n = binary.length; i < n; i++) {
var x = binary[i]
view.setInt8(i * 8, x)
}
Wondering if I have to worry about endianess or anything like that.
Or perhaps doing something with URL and blobs might be better, I'm not sure.

Yes, you are correct, in order to inline wasm modules and avoid the HTTP request, you'll have to perform some sort of encoding. I'd recommend using Base64 encoded strings as they are the most compact form.
You can encode as follows:
const readFileSync = require('fs').readFileSync;
const wasmCode = readFileSync(id);
const encoded = Buffer.from(wasmCode, 'binary').toString('base64');
You can then load the module as follows:
var encoded = "... contents of encoded from above ...";
function asciiToBinary(str) {
if (typeof atob === 'function') {
// this works in the browser
return atob(str)
} else {
// this works in node
return new Buffer(str, 'base64').toString('binary');
}
}
function decode(encoded) {
var binaryString = asciiToBinary(encoded);
var bytes = new Uint8Array(binaryString.length);
for (var i = 0; i < binaryString.length; i++) {
bytes[i] = binaryString.charCodeAt(i);
}
return bytes.buffer;
}
var module = WebAssembly.instantiate(decode(encoded), {});

Javascript: Uint16Array(length) returns Invalid argument

I'm trying to read a file in order to perform certain actions on the binary data before sending it to a server.
At a certain point I'm trying to convert the data returned by FileReader.readAsArrayBuffer() to an Uint16Array(). However upon doing so the code allocating the array fails with: 'Error: invalid arguments'. I need the data to be a hex string representing the entire binary.
This is the code I'm using:
function HexToHexString(ByteBuffer)
{
//Similar constructs like: 'var Array = new Uint16Array(ByteBuffer);' also fail
var View = new DataView(ByteBuffer);
var Array = new Uint16Array((ByteBuffer.byteLength / 2)); // <- this line fails
for(var i = 0; i < Array.length; i++)
{
Array[i] = View.getUint16(i*2);
}
return String.fromCharCode.apply(null, Array);
}
function OnReadFileCompletion(FileReadEvent)
{
if(FileReadEvent.target.readyState == FileReader.DONE)
{
// Debug code, will be replaced:
document.getElementById('byte_content').textContent = HexToHexString(FileReadEvent.target.result);
//FileReadEvent.target.result;
}
}
function ReadFile(File, ResultFunction)
{
var Reader = new FileReader();
Reader.onloadend = ResultFunction;
Reader.readAsArrayBuffer(File.slice(0, File.size - 1));
}
File Is a file object, ResultFunction is OnReadFileCompletion(), ByteBuffer is an '[object ArrayBuffer]'.
When I output the size of the ArrayBuffer it matches the size of the file (82kb). I'm on firefox 32 with no plugins installed.
I'm not a javascript programmer, does anyone know what I'm doing wrong?
Edit1:
It appears to have something to-do with the size of the file I'm trying to read, using a 1kb text file appears to work while a 82kb binary file does not.
Edit2
I spoke too soon, perhaps it has something to do with file types. An image file of 200kb works, while an executable of 82 does not.
It appears that javascript does not allow executable files to be accesed this way, does anybody know of any way where I could possibly access the data in hex form?

try using .length instead of byteLength

I've hacked together code that works for me, I don't know why this works or what I did wrong the other time. But it works.
function ApplyPadding(Number, PaddingLength)
{
var s = Number + "";
while (s.length < PaddingLength)
s = "0" + s;
return s;
}
function HexToHexString(ByteBuffers)
{
var AnArray = new Uint8Array(ByteBuffers);
var Result = "";
for(var i = 0; i < AnArray.length; i++)
{
if(i%2==0)
Result += ApplyPadding(AnArray[i].toString(16), 2);
}
return Result;
}
function HexStringToHex(aString)
{
var Buffer = new ArrayBuffer(aString.length*2); // 2 bytes for each char
var BufferView = new Uint16Array(Buffer);
for (var i = 0;i < aString.length; i++)
{
BufferView[i] = aString.charCodeAt(i);
}
return Buffer;
}
function OnReadFileCompletion(FileReadEvent)
{
if(FileReadEvent.target.readyState == FileReader.DONE)
{
//document.getElementById('byte_content').textContent =FileReadEvent.target.result;
var DataOfFile = HexStringToHex(FileReadEvent.target.result);
var FinalData = HexToHexString(DataOfFile);
document.getElementById('byte_content').textContent = FinalData;
//FileReadEvent.target.result;
}
}
function ReadFile(File, ResultFunction)
{
var Reader = new FileReader();
Reader.onloadend = ResultFunction;
Reader.readAsBinaryString(File.slice(0, File.size - 1));
}

how to convert object to binary string

Here is how I compress binary string (char codes above 255) with pako:
var charData = xhr.responseText.split('').map(function(x){return x.charCodeAt(0);});
var binData = new Uint8Array(charData);
var data = pako.deflate(binData, {level:"9"});
Here is how I decompress data back:
var data2 = pako.inflate(xhr.responseText);
Now, how can I get original string in JavaScript from this object?
I tried methods like this:
A.
pako.inflate(xhr.responseText, {to:"string"});
B.
String.fromCharCode.apply(null, data2);
C.
for (var i = 0, l = data2.length; i < l; i++)
{
result += String.fromCharCode(parseInt(array[i], 2));
}
All of these methods bring different data as JavaScript string than original.
When I save decompressed pako.inflate(xhr.responseText) to a file (using functions with a.download) then dempressed file has exactly the same bytes as original file (so compression and decompression works correctly, without any byte modification).

I am just trying to do the same and found a way to convert Object to binary string and vice versa. I just create a two function that converts JSON Object to Binary String and Binary String to JSON Object viz. covertObjectToBinary and convertBinaryToObject.
let obj = {a:1}
function covertObjectToBinary(obj) {
let output = '',
input = JSON.stringify(obj) // convert the json to string.
// loop over the string and convert each charater to binary string.
for (i = 0; i < input.length; i++) {
output += input[i].charCodeAt(0).toString(2) + " ";
}
return output.trimEnd();
}
function convertBinaryToObject(str) {
var newBin = str.split(" ");
var binCode = [];
for (i = 0; i < newBin.length; i++) {
binCode.push(String.fromCharCode(parseInt(newBin[i], 2)));
}
let jsonString = binCode.join("");
return JSON.parse(jsonString)
}
console.log('covertObjectToBinary =>', covertObjectToBinary(obj))
console.log('convertBinaryToObject =>', convertBinaryToObject(covertObjectToBinary(obj)))

Address to WCHAR_T to pass to ReadProcessMemory

I'm having trouble passing a WCHAR_T to ReadProcessMemory
This is how to succesfully pass a pointers address to ReadProcessMemory, I can do it with structures:
remote_tbb = ralloc_alloc(struct_TBButton.size);
var rez = SendMessage(hToolbar, TB_GETBUTTON, i, ctypes.voidptr_t(remote_tbb));
if (!rez) { throw new Error('Failed on SendMessage of TB_GETBUTTON') }
var local_tbb = new struct_TBButton();
var retRead = ralloc_read(remote_tbb, local_tbb.address());
var freed = ralloc_free(remote_tbb);
But now I need to do with WCHAR_T, so this is what I have:
var chars = SendMessage(hToolbar, TB_GETBUTTONTEXTW, local_tbb.idCommand, ctypes.voidptr_t(0));
console.log('chars=', chars, chars.toString(), uneval(chars));
if (chars && parseInt(chars.toString()) > 0) {
var remote_buf = ralloc_alloc(parseInt(chars.toString()));
var charsRe = SendMessage(hToolbar, TB_GETBUTTONTEXTW, local_tbb.idCommand, ctypes.voidptr_t(remote_buf));
console.log('charsRe=', charsRe);
var local_buf = ctypes.jschar; //WCHAR_T
var retRead = ralloc_read(remote_buf, local_buf.address()); ///PROBLEM LINE
console.log('retRead=', retRead);
var freed = ralloc_free(remote_buf);
console.log('freed=', freed);
console.log('Button Text = ', local_buf, local_buf.toString());
} else {
console.log('Button Text = NONE');
}
So my problem is on line:
var retRead = ralloc_read(remote_buf, local_buf.address());`
and it is specifically on the local_buf.address()
Errors in my experimenting that get thrown are:
expected type pointer, got ctypes.jschar
local_buf.address is not a function
So how to pass WCHAR_T as reference?
Edit:
Here is my ralloc_read implemetnation:
function ralloc_read(remote_address, local_buffer) {
var found_addr;
for (var i = 0; i < buffers.length; i++) {
if (buffers[i][0] == remote_address) {
found_addr = buffers[i]
break;
}
}
if (!found_addr) {
return null;
}
/*using the found remote address(found_addr[0]),
*i read size bytes (found_addr[1]) into my local_buffer*/
//console.info('found_addr[0]', found_addr[0].toString());
var rez = ReadProcessMemory(proc, found_addr[0], local_buffer, found_addr[1], 0);
return rez;
}

If ralloc_read calls ReadProcessMemory, then you'll need to allocate a jschar array that will receive the result.
var local_buf = ctypes.jschar.array()(chars);
ralloc_read(remote_buf, local_buf.address());
var str = local_buf.readString();
Edit However, the allocation call is wrong:
ralloc_alloc(parseInt(chars.toString()));
This will allocate chars bytes, e.g. chars = 11, 11 bytes.
A wchar_t/jschar however is not 1 byte but 2 bytes.
ctypes.jschar.size
// 2
So you'll actually need to allocate a remote memory buffer that is larger:
ralloc_alloc(parseInt(chars.toString()) * ctypes.jschar.size);
// That would be ralloc_alloc(count * sizeof(wchar_t*)) in C/C++
The local_buf stuff is correct, though as js-ctypes arrays will automatically calculate the required storage if it knows the size of the array element type, so a ctypes.jschar.array()(11) buffer will actually have 11 elements of size 2 bytes, i.e. 11 items * 2 bytes/item == 22 bytes.