crypto util

Utility functions for working with crypto keys in the browser or node.

This is some helpful functions that make it easier to work with cryptography. Note this does not deal with storing keys. Look at using @bicycle-codes/webauthn-keys (biometric authentication) or indexedDB for help with that.

This includes both sodium based keys and also webcrypto functions.

The Webcrypto keys are preferable because we create them as non-extractable keys, and are able to persist them in indexedDB, despite not being able to read the private key.

Tip

Request "persistent" storage with the .persist() method in the browser.

Note

The install size is kind of large (9.77 MB) because this includes a minified bundle of the sodium library.

Plus, See the docs generated from typescript

install

npm i -S @bicycle-codes/crypto-util

example

Create a new keypair

Use ECC keys with the web crypto API.

Also, you can use RSA keys.

import { create, KeyUse } from '@bicycle-codes/crypto-util'

// create a new keypair
const encryptKeypair = await create(KeyUse.Encrypt)
const signKeys = await create(KeyUse.Sign)

Use 2 ECC keypairs to create a new AES key

This requires a keypair + another keypair to derive a shared AES key.

import { getSharedKey } from '@bicycle-codes/crypto-util/webcrypto/ecc'
import { KeyUse } from '@bicycle-codes/crypto-util/types'

const alicesKeys = await createEcc(KeyUse.Encrypt)
const bobsKeys = await createEcc(KeyUse.Encrypt)

// pass in our private key, their public key
const sharedKey = await getSharedKey(alicesKeys.privateKey, bobsKeys.publicKey)

Bob can derive the same key by using their private key + Alice's public key.

const bobsSharedKey = await getSharedKey(bobsKeys.privateKey, alicesKeys.publicKey)

Encrypt with AES keys

Encrypt a given message with a given key.

import { create, encrypt } from '@bicycle-codes/crypto-util/webcrypto/aes'

const aesKey = await create()
const aesEncryptedText = await encrypt('hello AES', aesKey)

Decrypt with AES keys

import { decrypt } from '@bicycle-codes/crypto-util/webcrypto/aes'

const decrypted = await decrypt(aesEncryptedText, aesKey)

encrypt with ECC keys

This is a message from Alice to Bob. We use Alice's private key & Bob's public key.

import { KeyUse } from '@bicycle-codes/crypto-util'
import {
    create,
    encrypt,
    decrypt
} from '@bicycle-codes/crypto-util/webcrypto'

const alicesKeys = await create(KeyUse.Encrypt)
const bobsKeys = await create(KeyUse.Encrypt)
const eccEncryptedText = await encrypt(
    'hello ecc',
    alicesKeys.privateKey,
    bobsKeys.publicKey
)

Decrypt with ECC keys

Bob can decrypt the message encrypted by Alice, because we used bob's public key when encrypting it.

// note keys are reversed here --
// alice's public key and bob's private key
const decrypted = await decrypt(
    eccEncryptedText,
    bobsKeys.privateKey,
    alicesKeys.publicKey
)

// => 'hello ecc'

Create a signing keypair

Create another keypair that is used for signatures.

import { KeyUse } from '@bicycle-codes/crypto-util'
import { create } from '@bicycle-codes/crypto-util/webcrypto'

const eccSignKeys = await create(KeyUse.Sign)

Create signatures

import { sign } from '@bicycle-codes/crypto-util/webcrypto/ecc'

const sig = await sign('hello dids', eccSignKeys.privateKey)

Create a DID

A DID is a decentralized identifier, a string the encodes a user's public key.

If you are transmiting your public key along with a message, for example, this is the preferred format.

import { publicKeyToDid } from '@bicycle-codes/crypto-util'

const did = await publicKeyToDid(eccSignKeys.publicKey)

Verify a signature

Use a DID to verify a signature string.

import { verifyWithDid, sign } from '@bicycle-codes/crypto-util/ecc'

const sig = await sign('hello dids', eccSignKeys.privateKey)
const isOk = await verifyWithDid('hello dids', sig, did)

API

See the API docs

This exposes ESM and common JS via package.json exports field.

ESM

import * as util from '@bicycle-codes/crypto-utils'

Common JS

const util = require('@bicycle-codes/crypto-utils')

pre-built JS

This package exposes minified, pre-bundled JS files too. Copy them to a location that is accessible to your web server, then link in HTML.

copy

cp ./node_modules/@bicycle-codes/crypto-util/dist/index.min.js ./public/crypto-util.js

HTML

<script type="module" src="./crypto-util.js"></script>

webcrypto vs sodium

To use the webcrypto API, import from the webcrypto sub-path.

webcrypto API

This depends on an environment with a webcrypto API.

import { aes, ecc, rsa } from '@bicycle-codes/crypto-util/webcrypto'

example

import { rsa, ecc, aes } from '@bicycle-codes/crypto-util/webcrypto'

// create some ECC keypairs
const eccKeypair = await ecc.create(KeyUse.Sign)
const eccSignKeys = await ecc.create(KeyUse.Encrypt)

// get the public key as a string
const publicKey = await ecc.exportPublicKey(eccSignKeys.publicKey)

// get the public key as a DID format string
const did = await ecc.publicKeyToDid(eccSignKeys.publicKey)

// transform a DID string to a public key instance
const publicKey = ecc.didToPublicKey(eccDid)

webcrypto AES API

`aes.create`

Create a new AES-GCM key.

function create (opts:{ alg, length } = {
    alg: DEFAULT_SYMM_ALGORITHM,
    length: DEFAULT_SYMM_LEN
}):Promise<CryptoKey>

`aes.create` example

import { create } from '@bicycle-codes/crypto-util/webcrypto/aes'

const aesKey = await createAes()

`aes.encrypt`

Encrypt a string.

async function encrypt (
    msg:Msg,
    key:SymmKey|string,
    opts?:Partial<SymmKeyOpts>
):Promise<string>

import { encrypt } from '@bicycle-codes/crypto-util/webcrypto/aes'

let aesEncryptedText:string
test('encrypt some text with AES', async t => {
    aesEncryptedText = await encrypt('hello AES', aesKey)
    // returns a string by default
})

`aes.decrypt`

async function decrypt (
    msg:Msg,
    key:SymmKey|string,
    opts?:Partial<SymmKeyOpts>,
    charSize:CharSize = DEFAULT_CHAR_SIZE
):Promise<string>

import { decrypt } from '@bicycle-codes/crypto-util/webcrypto/aes'

const decrypted = await decrypt(aesEncryptedText, aesKey)
// => 'hello AES'

webcrypto RSA API

We expose RSA because not all browser yet support ECC keys. See ./src/rsa/webcrypto.ts and ./test/index.ts.

webcrypto ECC API

`ecc.create`

async function create (
    use:KeyUse,
    curve:EccCurve = EccCurve.P_256,
):Promise<CryptoKeyPair>

`create` example

import { create } from '@bicycle-codes/crypto-util/webcrypto/ecc'

const alicesEncryptionKeys = await createEcc(KeyUse.Encrypt)
const alicesSigningKeys = await createEcc(KeyUse.Sign)

`sign`

async function sign (
    msg:Msg,  // <-- string or Uint8Array
    privateKey:PrivateKey,
    { format }:{ format: 'base64'|'raw' } = { format: 'base64' },
    charSize:CharSize = DEFAULT_CHAR_SIZE,
    hashAlg:HashAlg = DEFAULT_HASH_ALGORITHM,
):Promise<ArrayBuffer|string>

example

import { sign } from '@bicycle-codes/crypto-util/webcrypto/ecc'

const sig = await sign('hello webcrypto', eccSignKeys.privateKey)

`verifyWithDid`

Verify a signature with a DID format string.

async function verifyWithDid (
    msg:string,
    sig:string,
    did:DID
):Promise<boolean>

import { verifyWithDid } from '@bicycle-codes/crypto-util/webcrypto/ecc'

const isOk = await verifyWithDid('hello dids', sig, did)

`getSharedKey`

Get a shared key given two existing keypairs.

async function getSharedKey (
    privateKey:PrivateKey,
    publicKey:PublicKey,
    opts?:Partial<{
        alg:'AES-GCM'|'AES-CBC'|'AES-CTR'
        length:SymmKeyLength
        iv:ArrayBuffer
    }>
):Promise<SymmKey>

let BobsKeys:CryptoKeyPair
let sharedKey:CryptoKey

const BobsKeys = await createEcc(KeyUse.Encrypt)
const sharedKey = await getSharedKey(eccKeypair.privateKey, BobsKeys.publicKey)
t.ok(sharedKey instanceof CryptoKey, 'should return a `CryptoKey`')

`encrypt`

Encrypt something with your private key and the recipient's public key.

async function encrypt (
    msg:Msg,  // <-- string or Uint8Array
    privateKey:PrivateKey,
    publicKey:string|PublicKey,  // <-- base64 or key
    { format }:{ format: 'base64'|'raw' } = { format: 'base64' },
    charSize:CharSize = DEFAULT_CHAR_SIZE,
    curve:EccCurve = DEFAULT_ECC_CURVE,
    opts?:Partial<{
        alg:SymmAlg
        length:SymmKeyLength
        iv:ArrayBuffer
    }>
):Promise<Uint8Array|string>

example

const eccEncryptedText = await ecc.encrypt(
    'hello ecc',
    alicesKeys.privateKey,
    BobsKeys.publicKey
)

`decrypt`

Decrypt some text that was encrypted with ecc.ecncrypt.

async function decrypt (
    msg:Msg,  // <-- string or Uint8Array
    privateKey:PrivateKey,
    publicKey:string|PublicKey,
    curve:EccCurve = DEFAULT_ECC_CURVE,
    opts?:Partial<{
        alg:'AES-GCM'|'AES-CBC'|'AES-CTR'
        length:SymmKeyLength
        iv:ArrayBuffer
    }>
):Promise<string>

example

Note the keys a swapped here -- the public and private keys can come from either keypair and it still works.

const decrypted = await ecc.decrypt(
    eccEncryptedText,
    BobsKeys.privateKey,
    alicesKeys.publicKey
)

sodium API

These should work anywhere that JS can run.

import { aes, ecc, rsa } from '@bicycle-codes/crypto-util/sodium'

Or import individual modules

import * as aes from '@bicycle-codes/crypto-util/sodium/aes'
import * as ecc from '@bicycle-codes/crypto-util/sodium/ecc'
import * as webcryptoAes from '@bicycle-codes/crypto-util/webcrypto/aes'

Sodium AES API

Encrypt with AEGIS-256 (symmetric crypto).

Sodium + AES example

import {
    create,
    encrypt,
    decrypt
} from '@bicycle-codes/crypto-util/sodium/aes'

// create a new key
const key = await create()

// or create a key, return a Uint8Array
const keyAsBuffer = await createAes({ format: 'raw' })

// encrypt something
const encryptedString = await encrypt('hello sodium + AES', key)

`aes.create`

Create a new AES key. Pass { format: 'raw' } to return a Uint8Array.

async function create (opts:{
    format: 'string'|'raw'
} = { format: 'string' }):Promise<Uint8Array|string>

example

import { create } from '@bicycle-codes/crypto-util/sodium/aes'

const aesKey = await create()

`aes.encrypt`

Encrypt the given string or buffer. Pass { format: 'raw' } to return a Uint8Array.

async function encrypt (
    msg:Uint8Array|string,
    key:Uint8Array|string,
    opts:Partial<{
        iv?:Uint8Array
        format?:'string'|'raw'
    }> = { format: 'string' },
):Promise<Uint8Array|string>

example

import { encrypt } from '@bicycle-codes/crypto-util/sodium/aes'

const encryptedString = await encryptAes('hello sodium + AES', aesKey)

`aes.decrypt`

Decrypt the given string or buffer. Pass { format: 'raw' } to return a Uint8Array.

async function decrypt (
    cipherText:string|Uint8Array,
    key:string|Uint8Array,
    opts:{ format:'string'|'raw' } = { format: 'string' }
):Promise<Uint8Array|string>

example

import { decrypt } from '@bicycle-codes/sodium/aes'

const decrypted = await decrypt(encryptedAes, aesKey)
// => "hello sodium + AES"

Sodium ECC API

Sodium + ECC example

import * as ecc from '@bicycle-codes/crypto-util/sodium/ecc'

const keys = await ecc.create()

`ecc.create`

Create a new Edward keypair.

async function create (
    use:KeyUse,
    curve:EccCurve = EccCurve.P_256,
):Promise<CryptoKeyPair>

`.create` example

import { create } from '@bicycle-codes/crypto-util/sodium/ecc'

const keys = await create()

`ecc.sign`

Create a signature for the diven data. Pass { format: 'raw' } to get a Uint8Array instead of a string.

async function sign (
    data:string|Uint8Array,
    key:LockKey,
    opts:{
        format:'string'|'raw'
    } = { format: 'string' }
):Promise<string|Uint8Array>

`ecc.sign` example

import { sign } from '@bicycle-codes/crypto-util/webcrypto/ecc'

const sig = await sign('hello webcrypto', alicesKeys, { format: 'raw' })

`ecc.publicKeyToDid`

Take a public key instance and return a DID format string.

async function publicKeyToDid (
    publicKey:Uint8Array|PublicKey
):Promise<DID>

`ecc.publicKeyToDid` example

import {
  exportPublicKey,
  publicKeyToDid
} from '@bicycle-codes/crypto-util/webcrypto/ecc'

const arr = await exportPublicKey(eccSignKeys.publicKey)
const did = await publicKeyToDid(arr)

`ecc.verify`

Verify the given signature + public key + message data.

async function verify (
    msg:Msg,  // <-- string or Uint8Array
    sig:string|Uint8Array|ArrayBuffer,
    publicKey:string|PublicKey,
    charSize:CharSize = DEFAULT_CHAR_SIZE,
    curve:EccCurve = DEFAULT_ECC_CURVE,
    hashAlg: HashAlg = DEFAULT_HASH_ALGORITHM
):Promise<boolean>

`ecc.verify` example

const key = await importDid(eccDid)
const isOk = await verify('hello webcrypto', sig, key)
t.ok(isOk, 'should verify a valid signature')

`ecc.verifyWithDid`

Verify the given signature + message + public key are ok together, using the given DID string as public key material.

async function verifyWithDid (
    msg:string,
    sig:string,
    did:DID
):Promise<boolean>

`ecc.verifyWithDid` example

import { verifyWithDid } from '@bicycle-codes/crypto-util/webcrypto/ecc'

const isOk = await verifyWithDid('hello dids', sig, did)

`ecc.encrypt`

Use the given private and public keys to create a shared key, then encrypt the message with the key.

async function encrypt (
    msg:Msg,
    privateKey:PrivateKey,
    publicKey:string|PublicKey,  // <-- base64 or key
    { format }:{ format: 'base64'|'raw' } = { format: 'base64' },
    charSize:CharSize = DEFAULT_CHAR_SIZE,
    curve:EccCurve = DEFAULT_ECC_CURVE,
    opts?:Partial<{
        alg:SymmAlg
        length:SymmKeyLength
        iv:ArrayBuffer
    }>
):Promise<Uint8Array|string>

`ecc.encrypt example`

import { encrypt } from '@bicycle-codes/crypto-util/webcrypto/ecc'

const eccEncryptedText = await encrypt(
    'hello ecc',
    AlicesKeys.privateKey,
    BobsKeys.publicKey
)

`ecc.decrypt`

Decrypt a message given a public and private key. Note in the example, the keypairs are reversed from the encrypt example. This creates a new shared key via Diffie Hellman.

import { decrypt } from '@bicycle-codes/crypto-util/webcrypto/ecc'

const decrypted = await decrypt(
    eccEncryptedText,
    BobsKeys.privateKey,
    AlicesKeys.publicKey
)

Name		Name	Last commit message	Last commit date
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.github		.github
src		src
test		test
.eslintignore		.eslintignore
.eslintrc		.eslintrc
.gitignore		.gitignore
.npmignore		.npmignore
.npmrc		.npmrc
.whitesource		.whitesource
CHANGELOG.md		CHANGELOG.md
LICENSE		LICENSE
NOTES.md		NOTES.md
README.md		README.md
lib.es5.d.ts		lib.es5.d.ts
package.json		package.json
tsconfig.build.json		tsconfig.build.json
tsconfig.json		tsconfig.json

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crypto util

Contents

install

example

Create a new keypair

Use 2 ECC keypairs to create a new AES key

Encrypt with AES keys

Decrypt with AES keys

encrypt with ECC keys

Decrypt with ECC keys

Create a signing keypair

Create signatures

Create a DID

Verify a signature

API

ESM

Common JS

pre-built JS

copy

HTML

webcrypto vs sodium

webcrypto API

example

webcrypto AES API

aes.create

aes.create example

aes.encrypt

aes.decrypt

webcrypto RSA API

webcrypto ECC API

ecc.create

create example

sign

example

verifyWithDid

getSharedKey

encrypt

example

decrypt

example

sodium API

Sodium AES API

Sodium + AES example

aes.create

example

aes.encrypt

example

aes.decrypt

example

Sodium ECC API

Sodium + ECC example

ecc.create

.create example

ecc.sign

ecc.sign example

ecc.publicKeyToDid

ecc.publicKeyToDid example

ecc.verify

ecc.verify example

ecc.verifyWithDid

ecc.verifyWithDid example

ecc.encrypt

ecc.encrypt example

ecc.decrypt

see also

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Contributors 3

`aes.create`

`aes.create` example

`aes.encrypt`

`aes.decrypt`

`ecc.create`

`create` example

`sign`

`verifyWithDid`

`getSharedKey`

`encrypt`

`decrypt`

`aes.create`

`aes.encrypt`

`aes.decrypt`

`ecc.create`

`.create` example

`ecc.sign`

`ecc.sign` example

`ecc.publicKeyToDid`

`ecc.publicKeyToDid` example

`ecc.verify`

`ecc.verify` example

`ecc.verifyWithDid`

`ecc.verifyWithDid` example

`ecc.encrypt`

`ecc.encrypt example`

`ecc.decrypt`