🔏 Lamport One-Time Signatures 🔏

Lamport one-time signature scheme is a simple but effective mechanism for creating signatures built on top of hash functions. Any cryptograph hash function can be used to implement the scheme. Signatures using large hash functions are understood so far to be "quantum resistant"

⚠ Warning ⚠

The lamport one-time signature scheme uses 50% of your private key as the signature, this is why they are for one time use only.

Do not use a single private key to sign more than once piece of data.

Installation

With npm

npm install --save lamport-ots

With yarn

yarn add lamport-ots

Usage

Basic usage with SHA256 hash function

const lamportSHA256 = require('lamport')

const { publicKey, privateKey } = lamportSHA256.keys()

const message = 'Hello, world!'
const signature = lamportSHA256.sign(message, privateKey)

// elsewhere...

if (lamportSHA256.verify(message, signature, publicKey)) {
  // Authenticity of message confirmed
} else {
  // Falsified signature, or tampered message
}

With a custom hash function

const lamport = require('lamport')

const lamportSomeHash = lamport(function (stringOrBuffer) {
  return someHashFrom(stringOrBuffer)
})

const { publicKey, privateKey } = lamportSomeHash.keys()

const message = 'Hello, world!'
const signature = lamportSomeHash.sign(message, privateKey)

// elsewhere...

if (lamportSomeHash.verify(message, signature, publicKey)) {
  // Authenticity of message confirmed
} else {
  // Falsified signature, or tampered message
}

API

lamport(hash)

hash must be a function that accepts either a String or a Buffer, and returns a Buffer of fixed length.

Returns a lamport "instance" with the following methods

• keys()
• sign(message, privateKey)
• verify(message, signature, publicKey)

lamport(hash).keys

Returns an Object with a publicKey and privateKey property.

lamport(hash).sign(message, privateKey)

message must be either a String or a Buffer

privateKey should be a privateKey returned from keys that hasn't been used before.

Returns a Buffer representing the signature

lamport(hash).verify(message, signature, publicKey

message must be either a String or a Buffer

signature must be a Buffer

publicKey should be a publicKey returned from keys()

Returns a Boolean representing the validity of the signature

lamport.keys

lamport.sign

lamport.verify

The module exposes a lamport "instance" created with the sha256 hash function, which you can use directly.

Contributing

Contributions are welcome from anyone and everyone and the collaboration model used is the Collective Code Construction Contract