supercop.js (DFINITY variant)

orlp/ed25519 compiled to pure javascript using Emscripten

modifications

The public key generation has been changed as follows:

The private key is not hashed (skips step 1). The private key is directly pruned and used as a scalar (steps 2-4). The same modification applies in signatures.

example

signing and verifying stuff

var lib = require('supercop.js')

var seed = lib.createSeed()
var keys = lib.createKeyPair(seed)
var msg = new Buffer('hello there')
var sig = lib.sign(msg, keys.publicKey, keys.secretKey)
console.log(lib.verify(sig, msg, keys.publicKey)) // true

storing keypairs

var lib = require('supercop.js')
var fs = require('fs')

var seed = lib.createSeed()
var keys = lib.createKeyPair(seed)

fs.writeFileSync('keys.json', JSON.stringify({
  publicKey: keys.publicKey.toString('base64'),
  secretKey: keys.secretKey.toString('base64')
}))

loading keypairs

var fs = require('fs')

var keys = require('./keys.json')
keys = {
  publicKey: new Buffer(keys.publicKey, 'base64'),
  secretKey: new Buffer(keys.secretKey, 'base64')
}

api

var seed = lib.createSeed()

Generates a cryptographically-secure 32-byte seed.

var keys = lib.createKeyPair(seed)

Generates a pubkey from the provided 32-byte secret key with the following properties:

• keys.publicKey - A 32 byte public key as a buffer.
• keys.secretKey - The secret key

var sig = lib.sign(msg, publicKey, secretKey)

Signs a given message of any length.

• msg - A buffer of any length containing a message.
• publicKey - The public key to sign with as a buffer.
• secretKey - The private key to sign with as a buffer.
• sig - The resulting signature as a buffer of length 64 bytes.

var valid = lib.verify(sig, msg, publicKey)

Verifies a given signature goes with the message and key.

• sig - The signature to verify.
• msg - The message that the signature represents.
• publicKey - The public key used to generate the signature.
• valid - A boolean telling whether the signature is valid(true) or invalid(false).