@didkovsky/keys-converter v1.0.0

Elliptic curve's keys converter

Tool that can convert binary private or public key to pem and der formats. Also includes factory for KeyObject from @node/crypto.

Install

npm i @didkovsky/keys-converter

Example

random private key for (secp256k1)

9d8ce6ab12507d729b9d160d352a0be329ec73dbc8afa65d6e5570bb14a8f71f

pem

-----BEGIN EC PRIVATE KEY-----
MHQCAQEEIJ2M5qsSUH1ym50WDTUqC+Mp7HPbyK+mXW5VcLsUqPcfoAcGBSuBBAAK
oUQDQgAE4zjQ9EYcK1uUoF/eCboVjNVlCOFH58VV6RmyZfZzpSrQjltCJQVubOmt
LLD1FWKZv76d4H4UNc/0mN0LkMKGDw==
-----END EC PRIVATE KEY-----

der (hex)

307402010104209d8ce6ab12507d729b9d160d352a0be329ec73dbc8afa65d6e5570bb14a8f71fa00706052b8104000aa14403420004e338d0f4461c2b5b94a05fde09ba158cd56508e147e7c555e919b265f673a52ad08e5b4225056e6ce9ad2cb0f5156299bfbe9de07e1435cff498dd0b90c2860f

Supported curves

Usage

See /examples folder.

convert private key

const { PrivConverter, getCurves } = require('@didkovsky/keys-converter')

/**
 * Get list of supported curves
 */
const curves = getCurves()

/**
 * Create converter for specified curve.
 */
const converter = PrivConverter.for(curves.secp256k1)

/**
 * Some private key.
 */
const priv = Buffer.alloc(32, 0x1)

/**
 * GetPem string.
 */
const pem = converter.toPem(priv)

/*
-----BEGIN EC PRIVATE KEY-----
MHQCAQEEIAEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBoAcGBSuBBAAK
oUQDQgAEG4TFVnsSZECZXT7VqroFZdceGDRgSBn/nBf16dXdB49wvq+PWItUFQf+
1qZCxatC39+BIKf2Od5RItR6aajo0Q==
-----END EC PRIVATE KEY-----
*/
console.log(pem)

/**
 * Get der Buffer.
 */
const der = converter.toDer(priv)

// Buffer(118) [Uint8Array] [ ... ]
console.dir(der)

/**
 * Get KeyObject from @node/crypto
 */
const keyObj = converter.toKeyObject(priv)

// PrivateKeyObject { [Symbol(kKeyType)]: 'private' }
console.dir(keyObj)

convert public key

const { PubConverter, getCurves } = require('@didkovsky/keys-converter')
const { createECDH } = require('crypto')

/**
 * Get list of supported curves
 */
const curves = getCurves()

/**
 * Create converter for specified curve.
 */
const converter = PubConverter.for(curves.secp256k1)

/**
 * Create keypair
 */
const priv = Buffer.alloc(32, 0x1)
const ecdh = createECDH('secp256k1')
ecdh.setPrivateKey(priv)
const pub = ecdh.getPublicKey()

// BBuExVZ7EmRAmV0+1aq6BWXXHhg0YEgZ/5wX9enV3QePcL6vj1iLVBUH/tamQsWrQt/fgSCn9jneUSLUemmo6NE=
console.log(pub.toString('base64'))

/**
 * GetPem string.
 */
const pem = converter.toPem(pub)

/*
-----BEGIN PUBLIC KEY-----
MFYwEAYHKoZIzj0CAQYFK4EEAAoDQgAEG4TFVnsSZECZXT7VqroFZdceGDRgSBn/
nBf16dXdB49wvq+PWItUFQf+1qZCxatC39+BIKf2Od5RItR6aajo0Q==
-----END PUBLIC KEY-----
*/
console.log(pem)

/**
 * Get der Buffer.
 */
const der = converter.toDer(pub)

// Buffer(88) [Uint8Array] [ ... ]
console.dir(der)

/**
 * Get KeyObject from @node/crypto
 */
const keyObj = converter.toKeyObject(pub)

// PublicKeyObject { [Symbol(kKeyType)]: 'public' }
console.dir(keyObj)

sign

With createSign from @node/crypto

const { createSign } = require('crypto')
const { PrivConverter, getCurves } = require('@didkovsky/keys-converter')

/**
 * Get list of supported curves
 */
const curves = getCurves()

/**
 * Create converter for specified curve.
 */
const converter = PrivConverter.for(curves.secp256k1)
 
/**
 * Some private key.
 */
const priv = Buffer.alloc(32, 0x1)

/**
 * Get keyObject from @node/crypto
 */
const privObj = converter.toKeyObject(priv)

/**
 * Signing some message.
 */
const message = 'Hello world!'
const signer = createSign('sha256')
signer.update(message).end()
const signature = signer.sign(privObj)

// MEUCIDHplD47Iy3PaSspcMmAScvE8Acdwc+4nrlPJwq64oynAiEA5+kGFrOqaihg7OQekCae5eKNprwweT02cKNQ5MPBrAE=
console.log(signature.toString('base64'))

verify

With createVerify from @node/crypto

const { createVerify } = require('crypto')
const { PubConverter, getCurves } = require('@didkovsky/keys-converter')

/**
 * Get list of supported curves
 */
const curves = getCurves()

/**
 * Create converter for specified curve.
 */
const converter = PubConverter.for(curves.secp256k1)

/**
 * Raw public key in base64 (65 bytes)
 */
const pub = 'BBuExVZ7EmRAmV0+1aq6BWXXHhg0YEgZ/5wX9enV3QePcL6vj1iLVBUH/tamQsWrQt/fgSCn9jneUSLUemmo6NE='

/**
 * Get keyObject from @node/crypto
 */
const pubObj = converter.toKeyObject(Buffer.from(pub, 'base64'))

/**
 * Our test signature and message
 */
const message = 'Hello world!'
const signature = 'MEUCIDHplD47Iy3PaSspcMmAScvE8Acdwc+4nrlPJwq64oynAiEA5+kGFrOqaihg7OQekCae5eKNprwweT02cKNQ5MPBrAE='

/**
 * Verifiyng signature
 */
const verifier = createVerify('sha256')
verifier.update(message).end()
const result = verifier.verify(pubObj, Buffer.from(signature, 'base64'))

// true
console.log(result)