Introduction

ECC based Encryption/Decryption in JS/wasm and python based app. [ecc, wasm, js, python, rust]

This is a demo project on encrypted communication between UI & backend over http/s, and delegating all heavy lifting(encryption in this case) to wasm binary compiled from ecies rust crate(https://docs.rs/ecies/0.2.1/ecies). The js binding for ecies wasm binary is handled with ecies-wasm npm package.

UI is built with reactjs and backend is a flask based api server. Encryption scheme being used: ecies(ECC based hybrid encryption).

Workflow:

How ecies works?

src: https://cryptobook.nakov.com/asymmetric-key-ciphers/ecies-public-key-encryption

1. We start with V(senders pub-key) and m(plaintext message)
2. A pair of ephemeral keypair is generated. U(public key), u(private key)
3. A shared-secret is generated by V * u. Payload is encrypted with k_ENC(symmetric key derived from shared-secret). Here * is EC Point multiplication over finite fields(galios).

The whole deal about ECDH is, this shared-secret will be equal to U * v(senders private key)

4. The final encrypted payload is : U, ciphertext(mac code, encrypted plaintext_message)

Performance of ecies lies in:

• we only used symmetric encryption once,
• and just relied on ECDH.
• No expensive assymetric encryption at all.

How to start:

• Use docker compose. UI at: http://localhost:8999/

OR

• Run server:
  • Generate privyte key with python eciespy_demo.py, save content as flask-app/keys/private.ec.key

    cd flask-app
    python3 -m venv venv
    source venv/bin/activate
    pip install -r requirements.txt
    python app.py

• Run UI:
  • Update server host url in api.js

    cd ui-react-webapck
    yarn
    yarn start

Demo example:

• Get age, msg as input, create JSON payload, encrypt using Public Key, convert encrypted data to base64.
• call POST /data with payload
• Server decrypts base64 encoded payload, decrypts using private-key, send age, msg back in response.

Notes:

• ecies:
  • https://github.com/ecies
  • uses secp256k1:
    • https://billatnapier.medium.com/a-bluffers-guide-to-secp256k1-404e423e612
    • https://www.secg.org/sec2-v2.pdf :
      • page 4: summary
    • https://herongyang.com/EC-Cryptography/Introduction-to-Elliptic-Curves.html