miscreant.js

The best crypto you've never heard of, brought to you by Phil Rogaway

JavaScript-compatible TypeScript implementation of Miscreant: Advanced symmetric encryption library which provides the AES-SIV (RFC 5297), AES-PMAC-SIV, and STREAM constructions. These algorithms are easy-to-use (or rather, hard-to-misuse) and support encryption of individual messages or message streams.

AES-SIV provides nonce-reuse misuse-resistance (NRMR): accidentally reusing a nonce with this construction is not a security catastrophe, unlike it is with more popular AES encryption modes like AES-GCM. With AES-SIV, the worst outcome of reusing a nonce is an attacker can see you've sent the same plaintext twice, as opposed to almost all other AES modes where it can facilitate chosen ciphertext attacks and/or full plaintext recovery.

Help and Discussion

Have questions? Want to suggest a feature or change?

• Gitter: web-based chat about miscreant projects including miscreant.js
• Google Group: join via web or email ([email protected])

Security Notice

Though this library is written by cryptographic professionals, it has not undergone a thorough security audit, and cryptographic professionals are still humans that make mistakes.

USE AT YOUR OWN RISK

Installation

Via npm:

npm install miscreant

Via Yarn:

yarn install miscreant

Import Miscreant into your project with:

import * as miscreant from "miscreant";

Import

Import Miscreant into your project with the following:

import * as miscreant from "miscreant";

API: Symmetric Encryption (AEAD)

The Authenticated Encryption with Associated Data API, or AEAD API, is the recommended API for encrypting and decrypting data with Miscreant. It accepts a nonce, optional associated data (i.e. data you'd like to authenticate along with the encrypted message), and a message to encrypt.

When decrypting, the same nonce and associated data must be supplied as were passed at the time of encryption. If anything is amiss, e.g. if the ciphertext has been tampered with, the cipher will detect it and throw an error.

miscreant.AEAD.importKey()

The miscreant.AEAD.importKey() method creates a new instance of an AES-SIV AEAD encryptor/decryptor.

Syntax

miscreant.AEAD.importKey(keyData, algorithm[, provider = new miscreant.WebCryptoProvider()])

Parameters

• keyData: a Uint8Array containing the encryption key to use. Key must be 32-bytes (for AES-128) or 64-bytes (for AES-256), as SIV uses two distinct AES keys to perform its operations.
• algorithm: a string describing the algorithm to use. The following algorithms are supported:
  • "AES-SIV": CMAC-based construction described in RFC 5297. Slower but standardized and more common.
  • "AES-PMAC-SIV": PMAC-based construction. Supports potentially faster implementations, but is non-standard and only available in Miscreant libraries.
• provider: a cryptography provider that implements Miscreant's [ICryptoProvider] interface.

Return Value

The miscreant.AEAD.importKey() method returns a Promise that, when fulfilled, returns an AEAD encryptor/decryptor.

Example

import * as miscreant from "miscreant";

let keyData = new Uint32Array(32);

// Assuming window.crypto.getRandomValues is available
window.crypto.getRandomValues(keyData);

let key = await miscreant.AEAD.importKey(keyData, "AES-PMAC-SIV");

seal()

The seal() method encrypts a message along with an optional associated data value which will be authenticated along with the message.

Syntax

key.seal(plaintext, nonce[, associatedData = ""])

Parameters

• plaintext: Uint8Array data to be encrypted.
• nonce: a single-use value which MUST be unique per encrypted message. Can be any length, and use any uniqueness strategy you like, e.g. a counter or a cryptographically secure random number generator.
• associatedData: (optional) Uint8Array that will be authenticated along with the message (but not encrypted).

Return Value

The seal() method returns a Promise that, when fulfilled, returns a Uint8Array containing the resulting ciphertext.

Example

import * as miscreant from "miscreant";

let keyData = new Uint8Array(32);

// Assuming window.crypto.getRandomValues is available
window.crypto.getRandomValues(keyData);

let key = await miscreant.SIV.importKey(keyData, "AES-PMAC-SIV");

// Encrypt plaintext

let plaintext = new Uint8Array([2,3,5,7,11,13,17,19,23,29]);
let nonce = new Uint8Array(16);
window.crypto.getRandomValues(nonce);

let ciphertext = await key.seal(plaintext, nonce);

open()

The open() method decrypts a message which has been encrypted using AES-SIV or AES-PMAC-SIV.

Syntax

key.open(ciphertext, nonce[, associatedData = ""])

Parameters

• ciphertext: Uint8Array containing an encrypted message.
• nonce: Uint8Array supplied when the message was originally encrypted.
• associatedData: (optional) Uint8Array supplied when the message was originally encrypted.

Return Value

The open() method returns a Promise that, when fulfilled, returns a Uint8Array containing the decrypted plaintext.

Exceptions

If the message has been tampered with or is otherwise corrupted, the promise will be rejected with an IntegrityError.

Example

import * as miscreant from "miscreant";

let keyData = new Uint8Array(32);

// Assuming window.crypto.getRandomValues is available
window.crypto.getRandomValues(keyData);

let key = await miscreant.SIV.importKey(keyData, "AES-PMAC-SIV");

// Encrypt plaintext

let plaintext = new Uint8Array([2,3,5,7,11,13,17,19,23,29]);
let nonce = new Uint8Array(16);
window.crypto.getRandomValues(nonce);

let ciphertext = await key.seal(plaintext, nonce);

// Decrypt ciphertext
var decrypted = await key.open(ciphertext, nonce);

STREAM API

Miscreant implements an interface that permits incremental processing of encrypted data based on the STREAM construction, which is provably secure against a wide range of attacks including truncation and reordering attacks.

The API is provided in the form of miscreant.StreamEncryptor and miscreant.StreamDecryptor classes, which each take a per-STREAM key and nonce, and from there operate a message-at-a-time on input plaintext/ciphertext along with optional per-message associated data (i.e. data you'd like to authenticate along with the encrypted message).

miscreant.StreamEncryptor.importKey()

The miscreant.StreamEncryptor.importKey() method creates a new instance of a STREAM encryptor, capable of encrypting a stream of authenticated messages and ensuring their integrity, ordering, and termination.

Syntax

miscreant.StreamEncryptor.importKey(keyData, nonceData, algorithm[, provider = new miscreant.WebCryptoProvider()])

Parameters

• keyData: a Uint8Array containing the encryption key to use. Key must be 32-bytes (for AES-128) or 64-bytes (for AES-256), as SIV uses two distinct AES keys to perform its operations.
• nonceData: a 64-bit (8-byte) Uint8Array which MUST be unique to this message stream (for a given key).
• algorithm: a string describing the algorithm to use. The following algorithms are supported:
  • "AES-SIV": CMAC-based construction described in RFC 5297. Slower but standardized and more common.
  • "AES-PMAC-SIV": PMAC-based construction. Supports potentially faster implementations, but is non-standard and only available in Miscreant libraries.
• provider: a cryptography provider that implements Miscreant's [ICryptoProvider] interface.

Return Value

The miscreant.StreamEncryptor.importKey() method returns a Promise that, when fulfilled, returns a StreamEncryptor object.

Example

import * as miscreant from "miscreant";

let keyData = new Uint32Array(32);
let nonceData = new Uint8Array(8);

// Assuming window.crypto.getRandomValues is available
window.crypto.getRandomValues(keyData);
window.crypto.getRandomValues(nonceData);

let encryptor = await miscreant.StreamEncryptor.importKey(keyData, nonceData, "AES-PMAC-SIV");

seal()

The seal() method of miscreant.StreamEncryptor encrypts a message, and also takes an optional associated data value which will be authenticated along with the message (but not encrypted).

Note that unlike the AEAD API, STREAM encodes the position of the message into the message stream, so the order in which seal() is called is significant.

Syntax

encryptor.seal(plaintext, [lastBlock = false[, associatedData = ""]])

Parameters

• plaintext: Uint8Array data to be encrypted.
• lastBlock: (optional; default: false) is this the last block in the stream?
• associatedData: (optional) Uint8Array that will be authenticated along with the message (but not encrypted).

Return Value

The seal() method returns a Promise that, when fulfilled, returns a Uint8Array containing the resulting ciphertext.

Example

import * as miscreant from "miscreant";

let keyData = new Uint32Array(32);
let nonceData = new Uint8Array(8);

// Assuming window.crypto.getRandomValues is available
window.crypto.getRandomValues(keyData);
window.crypto.getRandomValues(nonceData);

let encryptor = await miscreant.StreamEncryptor.importKey(keyData, nonceData, "AES-PMAC-SIV");

// Encrypt plaintext

let msg1 = new Uint8Array([1,2]);
let msg2 = new Uint8Array([3,4,5]);
let msg3 = new Uint8Array([6,7,8,9]);

let ciphertext1 = await encryptor.seal(msg1);
let ciphertext2 = await encryptor.seal(msg2);
let ciphertext3 = await encryptor.seal(msg3, true);

miscreant.StreamDecryptor.importKey()

The miscreant.StreamDecryptor.importKey() method creates a new instance of a STREAM decryptor, capable of decrypting a previously encrypted stream of authenticated messages and ensuring their integrity, ordering, and termination.

Syntax

miscreant.StreamDecryptor.importKey(keyData, nonceData, algorithm[, provider = new miscreant.WebCryptoProvider()])

Parameters

• keyData: a Uint8Array containing the encryption key to use. Key must be 32-bytes (for AES-128) or 64-bytes (for AES-256), as SIV uses two distinct AES keys to perform its operations.
• nonceData: a 64-bit (8-byte) Uint8Array which MUST be unique to this message stream (for a given key).
• algorithm: a string describing the algorithm to use. The following algorithms are supported:
  • "AES-SIV": CMAC-based construction described in RFC 5297. Slower but standardized and more common.
  • "AES-PMAC-SIV": PMAC-based construction. Supports potentially faster implementations, but is non-standard and only available in Miscreant libraries.
• provider: a cryptography provider that implements Miscreant's [ICryptoProvider] interface.

Return Value

The miscreant.StreamDecryptor.importKey() method returns a Promise that, when fulfilled, returns a StreamDecryptor object.

Example

import * as miscreant from "miscreant";

let keyData = new Uint32Array(32);
let nonceData = new Uint8Array(8);

// Assuming window.crypto.getRandomValues is available
window.crypto.getRandomValues(keyData);
window.crypto.getRandomValues(nonceData);

let decryptor = await miscreant.StreamDecryptor.importKey(keyData, nonceData, "AES-PMAC-SIV");

open()

The open() method decrypts a stream of messages which has been encrypted using AES-SIV or AES-PMAC-SIV.

Syntax

decryptor.open(ciphertext, [lastBlock = false[, associatedData = ""]])

Parameters

• ciphertext: Uint8Array containing an encrypted message.
• lastBlock: (optional; default: false) is this the last block in the stream?
• associatedData: (optional) Uint8Array supplied when the message was originally encrypted.

Return Value

The open() method returns a Promise that, when fulfilled, returns a Uint8Array containing the decrypted plaintext.

Exceptions

If the message has been tampered with or is otherwise corrupted, the promise will be rejected with an IntegrityError.

Example

import * as miscreant from "miscreant";

let keyData = new Uint32Array(32);
let nonceData = new Uint8Array(8);

// Assuming window.crypto.getRandomValues is available
window.crypto.getRandomValues(keyData);
window.crypto.getRandomValues(nonceData);

let encryptor = await miscreant.StreamEncryptor.importKey(keyData, nonceData, "AES-PMAC-SIV");

// Encrypt plaintext

let msg1 = new Uint8Array([1,2]);
let msg2 = new Uint8Array([3,4,5]);
let msg3 = new Uint8Array([6,7,8,9]);

let ciphertext1 = await encryptor.seal(msg1);
let ciphertext2 = await encryptor.seal(msg2);
let ciphertext3 = await encryptor.seal(msg3, true);

// Decrypt ciphertext
let decryptor = await miscreant.StreamDecryptor.importKey(keyData, nonceData, "AES-PMAC-SIV");

var decrypted1 = await key.open(ciphertext1);
var decrypted2 = await key.open(ciphertext2);
var decrypted3 = await key.open(ciphertext3, true);

SIV API

The SIV API is a power-user API that allows you to make full use of the multiple header feature the SIV construction provides.

miscreant.SIV.importKey()

The miscreant.SIV.importKey() method creates a new instance of an AES-SIV encryptor/decryptor.

Syntax

miscreant.SIV.importKey(keyData, algorithm[, provider = new miscreant.WebCryptoProvider()])

Parameters

• keyData: a Uint8Array containing the encryption key to use. Key must be 32-bytes (for AES-128) or 64-bytes (for AES-256), as SIV uses two distinct AES keys to perform its operations.
• algorithm: a string describing the algorithm to use. The following algorithms are supported:
  • "AES-SIV": CMAC-based construction described in RFC 5297. Slower but standardized and more common.
  • "AES-PMAC-SIV": PMAC-based construction. Supports potentially faster implementations, but is non-standard and only available in Miscreant libraries.
• provider: a cryptography provider that implements Miscreant's [ICryptoProvider] interface.

Return Value

The miscreant.SIV.importKey() method returns a Promise that, when fulfilled, returns a SIV encryptor/decryptor.

Example

import * as miscreant from "miscreant";

let keyData = new Uint32Array(32);

// Assuming window.crypto.getRandomValues is available
window.crypto.getRandomValues(keyData);

let key = await miscreant.SIV.importKey(keyData, "AES-PMAC-SIV");

seal()

The seal() method encrypts a message along with a set of message headers known as associated data.

Syntax

key.seal(associatedData, plaintext)

Parameters

• associatedData: array of Uint8Array values containing data which won't be encrypted, but will be authenticated along with the message. This is useful for including a nonce for the message, ensuring that if the same message is encrypted twice, the ciphertext will not repeat.
• plaintext: a Uint8Array data to be encrypted.

Return Value

The seal() method returns a Promise that, when fulfilled, returns a Uint8Array containing the resulting ciphertext.

Example

import * as miscreant from "miscreant";

let keyData = new Uint8Array(32);

// Assuming window.crypto.getRandomValues is available
window.crypto.getRandomValues(keyData);

let key = await miscreant.SIV.importKey(keyData, "AES-PMAC-SIV");

// Encrypt plaintext

let plaintext = new Uint8Array([2,3,5,7,11,13,17,19,23,29]);
let nonce = new Uint8Array(16);
window.crypto.getRandomValues(nonce);

let ciphertext = await key.seal(plaintext, [nonce]);

open()

The open() method decrypts a message which has been encrypted using AES-SIV or AES-PMAC-SIV.

Syntax

key.open(associatedData, ciphertext)

Parameters

• associatedData: array of Uint8Array values supplied as associated data when the message was originally encrypted.
• ciphertext: a Uint8Array containing an encrypted message.

Return Value

The open() method returns a Promise that, when fulfilled, returns a Uint8Array containing the decrypted plaintext.

If the message has been tampered with or is otherwise corrupted, the promise will be rejected with an IntegrityError.

Example

import * as miscreant from "miscreant";

let keyData = new Uint8Array(32);

// Assuming window.crypto.getRandomValues is available
window.crypto.getRandomValues(keyData);

let key = await SIV.importKey(keyData, "AES-PMAC-SIV");

// Encrypt plaintext

let plaintext = new Uint8Array([2,3,5,7,11,13,17,19,23,29]);
let nonce = new Uint8Array(16);
window.crypto.getRandomValues(nonce);

let ciphertext = await key.seal(plaintext, [nonce]);

// Decrypt ciphertext
var decrypted = await key.open(ciphertext, [nonce]);

Code of Conduct

We abide by the Contributor Covenant and ask that you do as well.

For more information, please see CODE_OF_CONDUCT.md.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/miscreant/miscreant

Copyright

Copyright (c) 2017-2019 The Miscreant Developers.

Software AES implementation derived from the Go standard library: Copyright (c) 2012 The Go Authors. All rights reserved.

See LICENSE.txt for further details.