kruptein

kruptein
========
crypto (krip-toh); from kruptein to hide or conceal.

!Downloads
!Build Status

Sandbox
-------
This started as an exercise in understanding, now has useful functionality.

Here you can experiment with the module to ensure it will suit your needs. kruptein

Install
-------
To install npm install kruptein

Methods
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* .set(secret, plaintext, [aad], callback)
* .get(secret, ciphertext, [{at: auth_tag, aad: aad}], callback)

Options
-------
Industry standards are used for the algorithm, hashing algorithm, key & IV sizes.
The default key derivation function is pbkdf2, however use of the scrypt or argon2 can be used as well.

* algorithm: (Optional) Cipher algorithm from crypto.getCiphers(). Default: aes-256-gcm.
* hashing: (Optional) Hash algorithm from crypto.getHashes(). Default: sha384.
* encodeas: (Optional) Output encoding. Currently supports binary, hex, & base64. Default: base64.
* key_size: (Optional) Key size bytes (should match block size of algorithm). Default: 32
* iv_size: (Optional) IV size bytes. Default: 16.
* at_size: (Optional) Authentication tag size. Applicable to gcm & ocb cipher modes. Default: 128.
* use_scrypt: (Optional) Use .scrypt() to derive a key. Requires node > v10. Default/Fallback: .pbkdf2().
* use_argon2: (Optional) Use .argon2id() to derive a key. Requires node > v24. Default/Fallback: .pbkdf2().
* use_asn1: (Optional) Disable the default ASN.1 encoding. Default: true

Usage
-----
When selecting an algorithm from crypto.getCiphers() the
iv and key_size values are calculated auto-magically to make implementation
easy.

You can always define your own if the defaults per algorithm and mode
aren't what you would like; see the options section above.

The secret must meet complexity requirements

Create ciphertext from plaintext
-----------------
An example of creating a new ciphertext object.

``javascript
const kruptein = require("kruptein")(opts);
let secret = "S3cre+_Squ1rr3l";

kruptein.set(secret, "Some kind of wonderfully private message", (err, ct) => {
if (err)
throw err;

console.log(ct);
});
`


Get plaintext from ciphertext
------------------
An example of retrieveing plaintext from a ciphertext object.

`javascript
const kruptein = require("kruptein")(opts);
let ciphertext, secret = "S3cre+_Squ1rr3l";

kruptein.get(secret, ciphertext, (err, pt) => {
if (err)
throw err;

console.log(pt);
});
`


Output
------
The .set() method output depends on three factors; the encodeas,
algorithm and use_asn1.

For any algorithm that supports authentication (AEAD), the object
structure includes the Authentication Tag and the Additional
Authentication Data attribute and value.

When the use_asn1 option is enabled (default is true), the result
is an ASN.1
value using the encodeas value. While this is a more complex
encoding option, it helps standardize & minimize the size of the
resulting ciphertext output.


Test harness
------------
The included test harness, invoked with npm test, makes every
attempt to trap and handle errors. Some of which come from side
channel or possible malability of the resultant ciphertext.

This can be seen within the test/index.js` CI test harness under
the HMAC, AT & AAD validation test cases.

References
-----------------------
This module conforms to industry recommendations regarding algorithm type,
mode, key size, iv size & implementation, digests, key derivation & management
etc. References used provided here:

RFC:
* RFC 2104: HMAC: Keyed-Hashing for Message Authentication
* RFC 4086: Randomness Requirements for Security
* RFC 5084: Using AES-CCM and AES-GCM Authenticated Encryption
* RFC 7914: The scrypt Password-Based Key Derivation Function
* RFC 8018: Password-Based Cryptography Specification
* RFC 9106: Argon2 Memory-Hard Function for Password Hashing and Proof-of-Work Applications
* X.697: ASN.1 encoding rules: Specifications of JavaScript Object Notation Encoding Rules (JER)

NIST:
* SP 800-38A: Block cipher modes of operation
* SP 800-38B: Recommendation for Block Cipher Modes of Operation: Galois/Counter Mode (GCM) and GMAC
* SP 800-57P1: Recommendations for key management
* SP 800-107: Recommendation for Applications Using Approved Hash Algorithms
* SP 800-108: Recommendation for Key Derivation Using Pseudorandom Functions
* SP 800-131A: Transitioning the Use of Cryptographic Algorithms and Key Lengths
* SP 800-132: Recommendation for Password-Based Key Derivation
* SP 800-175B: Guideline for Using Cryptographic Standards in the Federal Government

FIPS:
* FIPS 197: Advanced Encryption Standard (AES)
* FIPS 198-1: The Keyed-Hash Message Authentication Code (HMAC)
* FIPS 180-4: Secure Hash Standard (SHS)

Contributing
------------
Contributions are welcome & appreciated!

Refer to the contributing document
to help facilitate pull requests.

License
-------
This software is licensed under the MIT License.

Copyright Jason Gerfen, 2019.