altruist-encrypt

This is a simple npm package for encryption and decryption of data. It can be used for encryption of UTF-8 data that needs to be decrypted at a later time. This package combines both diffiehellman and rsa encryption approach and you can choose any of them depending on your preference and requirements.

⚠️ Note: This package is only compatible with Node.js environments. It does not support frontend frameworks like React or Angular.

Below is a short feature:

• RSA Encryption with signatures (for secure, verifiable messaging)
• Diffie-Hellman key exchange (for secure shared secrets over public networks)

Built entirely on the Node.js crypto module — no file storage for keys (in-memory only).

Features

• Generate RSA key pairs (in-memory)
• Sign and verify messages with RSA
• Encrypt and decrypt messages with RSA
• Perform secure Diffie-Hellman key exchange
• Encrypt and decrypt messages with shared Diffie-Hellman secrets
• Class-based, simple API
• No external dependencies
• Typescript Support

Installation

npm install altruist-encrypt

Or

yarn add altruist-encrypt

Quick Start

RSA Encryption

import { RSAEncryption } from "altruist-encrypt"

// Initialize
const rsa = new RSAEncryption()

// Generate key pair (public and private)
rsa.generateKeys()

const payload = "This is a sample test" or JSON.stringify({ name: "package" })

// Encrypt and sign (signature happens under the hood)
const encrypted: any = rsa.encrypt(JSON.stringify(payload))
console.log(encrypted) 

// Decrypt and verify (verification happens under the hood)
const decrypted: any = rsa.decrypt(encrypted.data, encrypted.signature)
console.log(decrypted)  

Diffie-Hellman

import { DiffieHellman } from "altruist-encrypt"

// Initialize
const encryption = new DiffieHellman()

// Generate initiator (sender) keys
const initiatorKeys = await encryption.getInitiatorKeys()

const payload = "This is a sample test" or JSON.stringify({ name: "package" })

// Encrypt
const encrypted = await encryption.encrypt(initiatorKeys.publicKey, payload)
console.log(encrypted) 

// Decrypt
const decrypted: any = await encryption.decrypt(encrypted.pubKey, { payload: encrypted.payload, salt: encrypted.salt })
console.log(decrypted)

API Reference

RSA Encryption

new RSAEncryption() Creates a new RSA handler instance

.generateKeys() Generates an RSA public-private key pair in memory

• Return void

.encrypt() Encrypts and signs a message using RSA.

• Parameters:
  • payload(string): Message to encrypt
• Returns:
  • { data: string; signature: string }
    • data: Base64 encrypted payload
    • signature: Base64 signature of original message

.decrypt(encryptedData: string, signature: string) Decrypts and verifies a message.

• Parameters:
  • encryptedData(string): Base64-encoded encrypted message
  • signature(string): Base64-encoded signature.
• Returns:
  • On success: Decrypted string
  • On failure: { error: string }

Diffie-Hellman

new DiffieHellmanEncryption() Creates a new Diffie-Hellman encryption instance

.getInitiatorKeys()

• Returns:
  • { publicKey: string, secretKey: string }
    • publicKey: Hexadecimal-encoded shared public key
    • secretKey: Hexadecimal-encoded shared secret key (should be ignored)

.encrypt(payload: string) Encrypts a message using the shared secret key (e.g., AES derived from the secret)

• Parameters:
  • payload(string): Plaintext to encrypt
• Returns: { payload: string, salt: string, pubKey: string } | { error: string }
  • On success:
    • payload(string): Hexadecimal encrypted text
    • salt(string): Random string used for salting
    • pubKey: Base64-encoded sender's public key. Needed to get the secret key from memory
  • On failure:
    • error: String returned if public key cannot be found in memory

.decrypt(publicKey, { payload:string, salt: string }) Decrypts a ciphertext using the shared secret key

• Parameters:
  • publicKey(string): Base64-encoded shared public key returned from encryption response
  • payload(string): Hexadecimal encrypted text returned from encryption response
  • salt: Random string returned from encryption response
• Returns: string | { error: string }
  • On success: Decrypted string
  • On failure: { error: string }

Security Notes

• RSA:
  • Ensures confidentiality via encryption
  • Ensures authenticity and integrity via signature verification
• Diffie-Hellman:
  • Enables secure key exchange even over insecure networks
  • Does not provide authentication — you should combine with signatures if needed

Note

• This package is designed for ephemeral communication — no keys are saved to files
• RSA operations are synchronous, suitable for most short-lived, lightweight encryption tasks

Licesne

MIT License