is there any builtin javascript string hash function in newest browsers?

Question

Everytime a new versions of browsers show up I hear about new stuff being added, like say webGL and other technologies that no one really knows if they catch up.

But I wonder if someone ever thought about such basic stuff in JS like hashing functions (MD5,SHA1 and the like).

By newest browsers I mean today's development versions too like Opera 12, Chrome 17 or Firefox 10.

Looking now for solution I found this comment on another thread here: https://stackoverflow.com/questions/7204097/short-hashing-function-for-javascript (Do you know that javascript objects already are hashtables ?). So what are these 'hashtables' ? Does it mean that I can make any string into a hash, but not an established one like md5 or sha1 but some JS build in specific ?

basically what I need to do is:

var txt="Hello world!";
var hash = txt.toSha1();

You appear to be confusing hash tables (an object which stores values against named keys, like {name: "bob", dob: "27/1/1970"}) with a hash function (a function for mapping a large data set to a small one, like md5) — Quentin
– Quentin, Commented Dec 29, 2011 at 17:14
Yes, now I understand that what I look for has nothing to do with hash tables. — rsk82
– rsk82, Commented Dec 29, 2011 at 17:19

Sam Bull · Accepted Answer · 2017-07-09 16:14:12Z

57

For anybody still looking for this information. There is a WebCrypto API which appears to have been finalised at the beginning of 2017.

To use it in a browser, you can find it at window.crypto.subtle which contains methods for encryption, digests etc. Documentation on the available functions here.

answered Jul 9, 2017 at 16:14

Sam Bull

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2 Comments

Tim Swena Over a year ago

Use the digest() function to get a hash of an array buffer. developer.mozilla.org/en-US/docs/Web/API/SubtleCrypto/digest

mb21 Over a year ago

To get this to work on a string (instead of array buffer), see below...

Yoz · Accepted Answer · 2021-12-06 09:24:14Z

9

async function sha256(source) {
    const sourceBytes = new TextEncoder().encode(source);
    const digest = await crypto.subtle.digest("SHA-256", sourceBytes);
    const resultBytes = [...new Uint8Array(digest)];
    return resultBytes.map(x => x.toString(16).padStart(2, '0')).join("");
}

answered Dec 6, 2021 at 9:24

Yoz

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2 Comments

AgainPsychoX Over a year ago

You can also use it in Node environments as crypto.webcrypto.subtle. So, you could write await (crypto.subtle || crypto.webcrypto.subtle).digest(...) (of course, it will throw if if not supported).

icc97 Over a year ago

this code is taken almost completely from the MDN Docs

Greg Guida · Accepted Answer · 2011-12-29 17:19:56Z

6

Paul Johnston has implemented the following algorithms in javascript

MD5, RIPEMD-160, SHA-1, SHA-256 and sha-512

You can find the source code and some examples here: http://pajhome.org.uk/crypt/md5/

I hope this is what you were looking for.

answered Dec 29, 2011 at 17:19

Greg Guida

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3 Comments

rsk82 Over a year ago

Well in sort of yes. But my question was about new developments in browsers, they put new function constantly and I wonder if they finally add hashes too. Is it ever planned, or by design must it that be because something is blocking this issue ?

Greg Guida Over a year ago

oh, I see, not that I know of in the context of the browser but if you're using node.js there is already a crypto package that handles these kinds of things

Mike 'Pomax' Kamermans Over a year ago

@rsk82 you probably want to accept the new WebCrypto answer then. Sure, it's been years, but future visitors are still finding this question looking for the same answer =)

Dipesh KC · Accepted Answer · 2022-08-01 03:36:26Z

-8

Note: This answer was written in 2014 when the Web Cryptography API was not available. Do not use this in the context where cryptographic security is needed. This may be useful when you need a simple reversible encryption with "builtin" support.

When I need simple client side hashing without external libraries I use the browsers' built in atob() and btoa() functions.

window.btoa() creates a base-64 encoded ASCII string from a "string" of binary data.

function utf8_to_b64( str ) {
    return window.btoa(encodeURIComponent( escape( str )));
}

The window.atob() function decodes a string of data which has been encoded using base-64 encoding.

function b64_to_utf8( str ) {
    return unescape(decodeURIComponent(window.atob( str )));
}

http://caniuse.com/#search=btoa and http://caniuse.com/#search=atob shows it is hugely supported by the modern browsers

Example taken from https://developer.mozilla.org/en-US/docs/Web/API/window.btoa

edited Aug 1, 2022 at 3:36

answered Aug 21, 2014 at 9:56

Dipesh KC

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2 Comments

ecmanaut Over a year ago

This is a useful reversible 1:1 encoding that turns plaintext into less plain, and larger output than the input. Both are opposites properties to those of the one-way cryptographic hash functions sought here.

mit Over a year ago

The op and the titel do not suggest that it has to be cryptographic and secure. The functions that the op mentions are not all secure or unbreakable. He asks for "and the like", and the focus seems on "builtin". This is a valid answer and it is helpful to some. There are many situations a hash value can be helpful where security is not the problem

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