bcrypt.js

Optimized bcrypt in JavaScript with zero dependencies. Compatible to the C++ bcrypt binding on node.js and also working in the browser.

Security considerations

Besides incorporating a salt to protect against rainbow table attacks, bcrypt is an adaptive function: over time, the iteration count can be increased to make it slower, so it remains resistant to brute-force search attacks even with increasing computation power. (see)

While bcrypt.js is compatible to the C++ bcrypt binding, it is written in pure JavaScript and thus slower (about 30%), effectively reducing the number of iterations that can be processed in an equal time span.

The maximum input length is 72 bytes (note that UTF8 encoded characters use up to 4 bytes) and the length of generated hashes is 60 characters.

Usage

The library is compatible with CommonJS and AMD loaders and is exposed globally as dcodeIO.bcrypt if neither is available.

node.js

On node.js, the inbuilt crypto module's randomBytes interface is used to obtain secure random numbers.

npm install bcryptjs

var bcrypt = require('bcryptjs');
...

Browser

In the browser, bcrypt.js relies on Web Crypto API's getRandomValues interface to obtain secure random numbers. If no cryptographically secure source of randomness is available, you may specify one through bcrypt.setRandomFallback.

var bcrypt = dcodeIO.bcrypt;
...

or

require.config({
    paths: { "bcrypt": "/path/to/bcrypt.js" }
});
require(["bcrypt"], function(bcrypt) {
    ...
});

Usage - Sync

To hash a password:

var bcrypt = require('bcryptjs');
var salt = bcrypt.genSaltSync(10);
var hash = bcrypt.hashSync("B4c0/\/", salt);
// Store hash in your password DB.

To check a password:

// Load hash from your password DB.
bcrypt.compareSync("B4c0/\/", hash); // true
bcrypt.compareSync("not_bacon", hash); // false

Auto-gen a salt and hash:

var hash = bcrypt.hashSync('bacon', 8);

Usage - Async

To hash a password:

var bcrypt = require('bcryptjs');
bcrypt.genSalt(10, function(err, salt) {
    bcrypt.hash("B4c0/\/", salt, function(err, hash) {
        // Store hash in your password DB.
    });
});

To check a password:

// Load hash from your password DB.
bcrypt.compare("B4c0/\/", hash, function(err, res) {
    // res === true
});
bcrypt.compare("not_bacon", hash, function(err, res) {
    // res === false
});

// As of bcryptjs 2.4.0, compare returns a promise if callback is omitted:
bcrypt.compare("B4c0/\/", hash).then((res) => {
    // res === true
});

Auto-gen a salt and hash:

bcrypt.hash('bacon', 8, function(err, hash) {
});

Note: Under the hood, asynchronisation splits a crypto operation into small chunks. After the completion of a chunk, the execution of the next chunk is placed on the back of JS event loop queue, thus efficiently sharing the computational resources with the other operations in the queue.

API

setRandomFallback(random)

Sets the pseudo random number generator to use as a fallback if neither node's crypto module nor the Web Crypto API is available. Please note: It is highly important that the PRNG used is cryptographically secure and that it is seeded properly!

| Parameter | Type | Description |-----------------|-----------------|--------------- | random | function(number):!Array.<number> | Function taking the number of bytes to generate as its sole argument, returning the corresponding array of cryptographically secure random byte values. | @see | | http://nodejs.org/api/crypto.html | @see | | http://www.w3.org/TR/WebCryptoAPI/

Hint: You might use isaac.js as a CSPRNG but you still have to make sure to seed it properly.

genSaltSync(rounds=, seed_length=)

Synchronously generates a salt.

| Parameter | Type | Description |-----------------|-----------------|--------------- | rounds | number | Number of rounds to use, defaults to 10 if omitted | seed_length | number | Not supported. | @returns | string | Resulting salt | @throws | Error | If a random fallback is required but not set

genSalt(rounds=, seed_length=, callback)

Asynchronously generates a salt.

| Parameter | Type | Description |-----------------|-----------------|--------------- | rounds | number | function(Error, string=) | Number of rounds to use, defaults to 10 if omitted | seed_length | number | function(Error, string=) | Not supported. | callback | function(Error, string=) | Callback receiving the error, if any, and the resulting salt | @returns | Promise | If callback has been omitted | @throws | Error | If callback is present but not a function

hashSync(s, salt=)

Synchronously generates a hash for the given string.

| Parameter | Type | Description |-----------------|-----------------|--------------- | s | string | String to hash | salt | number | string | Salt length to generate or salt to use, default to 10 | @returns | string | Resulting hash

hash(s, salt, callback, progressCallback=)

Asynchronously generates a hash for the given string.

| Parameter | Type | Description |-----------------|-----------------|--------------- | s | string | String to hash | salt | number | string | Salt length to generate or salt to use | callback | function(Error, string=) | Callback receiving the error, if any, and the resulting hash | progressCallback | function(number) | Callback successively called with the percentage of rounds completed (0.0 - 1.0), maximally once per MAX_EXECUTION_TIME = 100 ms. | @returns | Promise | If callback has been omitted | @throws | Error | If callback is present but not a function

compareSync(s, hash)

Synchronously tests a string against a hash.

| Parameter | Type | Description |-----------------|-----------------|--------------- | s | string | String to compare | hash | string | Hash to test against | @returns | boolean | true if matching, otherwise false | @throws | Error | If an argument is illegal

compare(s, hash, callback, progressCallback=)

Asynchronously compares the given data against the given hash.

| Parameter | Type | Description |-----------------|-----------------|--------------- | s | string | Data to compare | hash | string | Data to be compared to | callback | function(Error, boolean) | Callback receiving the error, if any, otherwise the result | progressCallback | function(number) | Callback successively called with the percentage of rounds completed (0.0 - 1.0), maximally once per MAX_EXECUTION_TIME = 100 ms. | @returns | Promise | If callback has been omitted | @throws | Error | If callback is present but not a function

getRounds(hash)

Gets the number of rounds used to encrypt the specified hash.

| Parameter | Type | Description |-----------------|-----------------|--------------- | hash | string | Hash to extract the used number of rounds from | @returns | number | Number of rounds used | @throws | Error | If hash is not a string

getSalt(hash)

Gets the salt portion from a hash. Does not validate the hash.

| Parameter | Type | Description |-----------------|-----------------|--------------- | hash | string | Hash to extract the salt from | @returns | string | Extracted salt part | @throws | Error | If hash is not a string or otherwise invalid

Command line

Usage: bcrypt <input> [salt]

If the input has spaces inside, simply surround it with quotes.

Downloads

• Distributions
• ZIP-Archive
• Tarball

Credits

Based on work started by Shane Girish at bcrypt-nodejs (MIT-licensed), which is itself based on javascript-bcrypt (New BSD-licensed).

License

New-BSD / MIT (see)