thecipherBlock

function determineSignByte(publicKey: string): string {
    
    if(publicKey.length !== 64) {
        throw new Error("required `public key` of length 32");
    }

    const xCoordinate = BigInt("0x" + publicKey);
    return xCoordinate % BigInt(2) === BigInt(0) ? "02" : "03";
}
 

thecipherBlock

import 'dart:typed_data';
import 'package:pointycastle/digests/keccak.dart';
import 'package:pointycastle/ecc/api.dart';
import 'package:pointycastle/ecc/curves/secp256k1.dart';

BigInt decodeToBigInt(List<int> magnitude) {
  BigInt result;

  if (magnitude.length == 1) {
    result = BigInt.from(magnitude[0]);

thecipherBlock

import 'dart:typed_data';
import 'package:convert/convert.dart';
import 'package:pointycastle/digests/keccak.dart';

/// This gist/function helps in convertion or verification of the ethereum address
/// Why checksum is explained here: https://coincodex.com/article/2078/ethereum-address-checksum-explained/
String toChecksum(String ethAddress) {
  // Checking for 0x prefix
  String addrWithoutChecksum = ethAddress.substring(0, 2) == '0x'
      ? ethAddress.substring(2, ethAddress.length)

thecipherBlock

var crypto = require("crypto");
var path = require("path");
var fs = require("fs");

var encryptStringWithRsaPublicKey = function(toEncrypt, publicKeyInPemPath) {
    var absolutePath = path.resolve(publicKeyInPemPath);
    var publicKey = fs.readFileSync(absolutePath, "utf8");
    var buffer = Buffer.from(JSON.stringify(toEncrypt));
    var encrypted = crypto.publicEncrypt(publicKey, buffer);
    return encrypted.toString("base64");