SECP256K1 Key Generation and Signature Verification

This repository contains two Node.js scripts:

1. keyGenaration.js

   • Generates a BIP39 mnemonic (or uses an existing mnemonic).
   • Derives a SECP256K1 private key using BIP32 path m/0.
   • Generates the corresponding uncompressed public key.

2. signatureverification.js

   • Signs a Base64-encoded message using a SECP256K1 private key.
   • Verifies the generated signature using the corresponding public key.

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Prerequisites

Ensure the following are installed:

• Node.js (v18 or later recommended)
• npm

Verify installation:

node -v
npm -v

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Clone the Repository

git clone https://github.com/rubixchain/BIP39JS
cd BIP39JS

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Initialize the Project

Create a Node.js project:

npm init -y

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Install Dependencies

Install all required packages:

npm install bip39 secp256k1 tiny-secp256k1 bip32 @noble/curves

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Repository Structure

.
├── keyGenaration.js
├── signatureverification.js
├── package.json
└── README.md

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Step 1: Generate Key Pair

Run:

node keyGenaration.js

The script outputs:

Mnemonic: ...
Private Key (hex): ...
Public Key (hex): ...

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Using an Existing Mnemonic

If you already have a mnemonic, replace:

const mnemonic = 'drip pudding region dress youth team vague black web deer hurdle limit device worry federal dizzy curious trash segment leaf decline fuel strike trick';

with your own mnemonic:

const mnemonic = 'your existing mnemonic words here';

Example:

const mnemonic = 'abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon about';

Then run:

node keyGenaration.js

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Generating a New Random Mnemonic

To generate a fresh mnemonic from randomly generated entropy:

Comment out:

const mnemonic = 'drip pudding region dress youth team vague black web deer hurdle limit device worry federal dizzy curious trash segment leaf decline fuel strike trick';

and uncomment:

const mnemonic = bip39.entropyToMnemonic(entropy.toString('hex'));

The code should look like:

const entropy = crypto.randomBytes(32);

const mnemonic = bip39.entropyToMnemonic(entropy.toString('hex'));

Then run:

node keyGenaration.js

A new mnemonic and key pair will be generated.

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Step 2: Sign and Verify a Message

Open:

signatureverification.js

Update the following variables:

const privKeyStr = "";
const pubKeyStr = "";
const message = "";

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Provide the Private Key

Use the private key generated by keyGenaration.js.

Example:

const privKeyStr = "4f5d3a4b1e2c...";

The value should be a hexadecimal string.

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Provide the Public Key

Use the public key generated by keyGenaration.js.

Example:

const pubKeyStr = "04f9a1b2c3d4...";

The value should be the full uncompressed public key generated by the script.

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Provide the Message

The script expects the message to be Base64 encoded.

Example:

const message = "5tZJVstcCmq3Cxum7u52y+nieWHma3Wawrbyi0tl0GQ=";

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Converting Plain Text to Base64

Example:

const text = "Hello World";
const base64 = Buffer.from(text).toString('base64');

console.log(base64);

Output:

SGVsbG8gV29ybGQ=

Use that value as:

const message = "SGVsbG8gV29ybGQ=";

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Run Signature Generation and Verification

Execute:

node signatureverification.js

Example output:

signature (Base64): MEQCIF...
signature size (toDERRawBytes): 71
Is signature valid? true

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Complete Workflow

Generate Keys

node keyGenaration.js

Output:

Mnemonic: ...
Private Key (hex): ...
Public Key (hex): ...

Copy Generated Keys

Update:

const privKeyStr = "<generated private key>";
const pubKeyStr = "<generated public key>";

inside:

signatureverification.js

Provide Message

Update:

const message = "<base64 encoded message>";

Sign and Verify

node signatureverification.js

Expected result:

Is signature valid? true

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Security Notes

• Never commit real mnemonics to source control.
• Never share private keys.
• Store mnemonics securely in an offline location.
• Treat anyone with access to the mnemonic as having access to the private key.
• Use test mnemonics only for development and testing purposes.