ecies | Elliptic Curve Integrated Encryption Scheme | Cryptography library

I want to encrypt and decrypt the message based on ECIES using this library JavaScript Elliptic curve cryptography library. I want to import my private key and get the public key from it because I do not have a new private key generated each time I run the code.

The code:

Intro:

So I am new to JavaScript and I would like to know how I can use the return from an async function without using .then or anything of that sort (if not, then is it possible to use this in a way that I can access the return in scope of the signupData() function). So I am encrypting things with ECIES scheme using Secp256k1 keys to be sent to the API for later usage, however, I think the .encrypt under the encryptMes section in the post invokes a promise. Below is relevant code:

signup.html

I've been having a really hard time figuring out how to store a Secp256k1 privateKey from multiple libraries (currently on this one for ECIES encryption: https://npm.io/package/@toruslabs/eccrypto).

I have tried encoding and decoding with base64, many implementations of functions that copy array buffer for input encoded string to localStoarge and corresponding output Uint8Array from localStorage, I tried it with IndexedDB, JSON.stringify and parse do not work with binary data, and so many more variations.

When I go through the array buffer elements individually to copy it into a new Uint8Array, I get a similar private key, but with two missing key/field's (parent and offset) which I believe is why every library I have tried so far returns something a long the lines of "bad private key" when I try generating the public key from them.

I am exhausted and I would like some professional insight for my lack of skill in this particular subject. So how can I store (in any way as long as it's client/local) a Secp256k1 private key in a way that if I call it from that persistent client sided data base, they can be used to generate the public keys?

It's been a few hours since I began reading about IndexedDB and I am having some issues. This is code I followed from https://medium.com/@AndyHaskell2013/build-a-basic-web-app-with-indexeddb-8ab4f83f8bda and https://gist.github.com/JamesMessinger/a0d6389a5d0e3a24814b and it's just put together poorly for comprehension's sake. So what I am trying to do is store a secret key into IndexedDB so that I can use it to encrypt things with the ECIES scheme.

Relevant code (sequential order):

I am using eccrypto library in javascript for encryption using the ECIES algorithm (curve- secp256k1). The cipher generated by encryption in JS code could not be decrypted in Kotlin.

Here is the Javascript code.

I have wrote a function to encrypt a string because it's a sensitive information. I was running some testes and I have identified that the generated output is different on each run.

I'm not sure if it's related to salt or something like that.

Is a normal behavior the output be different each time is called? Is it a good practice or a bad practice?

I cannot understand how to build Botan for android, according on the instruction here:

$ export CXX=/opt/android-ndk/toolchains/llvm/prebuilt/linux-x86_64/bin/aarch64-linux-android28-clang++

$ ./configure.py --os=android --cc=clang --cpu=arm64

i cannot understand how to use this commands on Windows, also reading previous issues did not help me, can you tell me how did you build this library on windows step-by-step, just your command examples?

I used --cc-bin option of configure.py to specify the path to the compiler, it is considered a solution for windows, but what i have is:

supposed we have global CryptoPP::ECIES::PrivateKey mykey initialized object ,and have 10 threads that run CryptoPP::ECIES::Encryptor myencrypto(mykey) for making a encryptor object by assigning key from mykey object

the assigner takes mykey as reference

do i need a Mutex to make sure that only one thread uses mykey at a time , or multi threads can assign enryptor from key object simultaneously without any problem (if yes , is that guaranteed)

(please note that threads only assign from the mykey simultaneously none of them modify it(my code doesn't don't know if the cryptoPP assigner does ))

I'm trying to Store ECIES num0 PrivateKey with DEREncodePrivateKey to a std::string and reload it in num1 PrivateKey Object for testing. Problem is when key is loaded with BERDecodePrivateKey in second PrivateKey object it can't be validated (also tested encryption and decrypting without validation and didn't decrypt )

here's the code