fernet
v0.3.2
Published
Javascript implementation of Fernet symmetric encryption https://github.com/kr/fernet-spec
Downloads
49,808
Readme
Fernet.js
Javascript implementation of Fernet symmetric encryption.
Fernet is an opinionated way of using AES and HMAC authentication that makes shared-secret symmetric encryption simpler for communicating applications.
Fernet.js uses browserify to provide a library that works in both node and the browser.
Instead of using TypedArrays I use Hex Strings and CryptoJS's Hex.parse
to build up CryptoJs.lib.WordArray
objects.
WARNING
It's generally never considered safe to encrypt data in the browser.
However, you can use this library to encrypt/decrypt data server-side and decrypt data on a client.
That being said, the only randomness used by this library without your control is a call to crypto.randomBytes
to generate IVs.
This function defaults to OpenSSL server-side and browserify's random number generator implementation
client-side. The browserify implementation only uses real browser crypto or throws an error. (IE: no calls to Math.random()
)
If you're planning on generating the secrets in the browser do yourself a favor and get an audit.
Use
node.js
var fernet = require('./fernet');
browser
<script src="fernetBrowser.js"></script>
Fernet
fernet.setSecret(string)
Sets the secret
at the top level for all further Tokens made
from this instance of Fernet.
fernet.ttl = seconds
Sets the ttl
at the top level for all further Tokens made
from this instance of Fernet.
Secret
Generating a secret
Generating appropriate secrets is beyond the scope of `Fernet`, but you should
generate it using `/dev/random` in a *nix. To generate a base64-encoded 256 bit
(32 byte) random sequence, try:
dd if=/dev/urandom bs=32 count=1 2>/dev/null | openssl base64
new fernet.Secret(string)
var secret = new fernet.Secret("cw_0x689RpI-jtRR7oE8h_eQsKImvJapLeSbXpwF4e4=");
/*
{
signingKeyHex: '730ff4c7af3d46923e8ed451ee813c87',
signingKey: [CryptoJS.lib.WordArray],
encryptionKeyHex: 'f790b0a226bc96a92de49b5e9c05e1ee',
encryptionKey: [CryptoJS.lib.WordArray]
}
*/
Token
new fernet.Token(options)
Options:
secret
: afernet.Secret
objecttoken
: a Fernet-encoded Stringttl
: seconds of ttl
For testing:
time
: Date objectiv
: Array of Integers
Token.prototype.encode
//Have to include time and iv to make it deterministic.
//Normally time would default to (new Date()) and iv to something random.
var token = new fernet.Token({
secret: secret,
time: Date.parse(1),
iv: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15]
})
token.encode("Message")
/*
'gAAAAABSO_yhAAECAwQFBgcICQoLDA0OD1PGoFV6wgWZG6AOBfQqevwJT2qKtCZ0EjKy1_TvyxTseR_3ebIF6Ph-xa2QT_tEvg=='
*/
Token.prototype.decode
Include tt
var token = new fernet.Token({
secret: secret,
token: 'gAAAAABSO_yhAAECAwQFBgcICQoLDA0OD1PGoFV6wgWZG6AOBfQqevwJT2qKtCZ0EjKy1_TvyxTseR_3ebIF6Ph-xa2QT_tEvg==',
ttl: 0
})
token.decode();
/*
"Message"
*/
Test
> npm test
Compiles new fernetBrowser.js via browserify
,
tests node lib with mocha
, then opens test.html via open
.