crypto stream

npm install --save crypto-stream

Streaming authenticated encryption, exports 2 functions encrypt and decrypt, both of which take a single argument being a buffer for the key.

var cryptoStream = require('crypto-stream');
 
var encrypter = cryptoStream.encrypt(getKeySomehow());
 
var decrypter = cryptoStream.decrypt(getKeySomehow());

How it works

Data is encrypted with AES in CTR mode. Key size is picked according to the size of the key you pass in. If the key is 16 bytes, 24 bytes, or 32 bytes it just picks the appropriate version of AES, if the key is some other size (and larger than 8 bytes) then the buffer is passed through sha256 and AES-256 is used. If it's smaller then 8 bytes an error is thrown because your key is too small.

When encrypting a 16 byte random salt is generated and passed at the beginning of the stream. When decrypting, this salt is extracted automatically.

A zeroed out buffer is encrypted and used as the key for an hmac-stream. Which the encrypted data is passed through and then is authenticated with before decryption.