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javascriptnode.jshashbackwards-compatibilitynode-crypto

Why crypto.createHash returns different output in new version?

Problem

I have node.js module that is using crypto.createHash to generate md5 hash.

Recently I noticed that hash generated by crypto module is different in new versions:

Code

require('crypto').createHash('md5').update('¥').digest('hex')

Node.js v0.10.0

Outputs: ab3af8566ddd20d7efc9b314abe90755

Node.js v6.1.0

Outputs: 07625e142e4ac5961de57472657a88c1

Question

I was wondering what causes that in new version and how can I solve this?

Update

Similar issues on GitHub:

Solution

  • Some inputs in Node v6+ calculate a different hash than previous Node versions.

    Basically, when you pass a string to .update(), with Node versions before v6 the default encoding was binary, but for Node v6 that changed to utf-8.

    For example, take this code:

    require('crypto').createHash('md5').update('¥').digest('hex')

    This outputs ab3af8566ddd20d7efc9b314abe90755 on Node pre-6 and 07625e142e4ac5961de57472657a88c1 on Node 6.

    If you want Node 6 to output the same as pre-6 versions, you have to tell .update() to use binary encoding:

    require('crypto').createHash('md5').update('¥', 'binary').digest('hex')

    Or the other way around (make Node pre-6 output the same as 6):

    require('crypto').createHash('md5').update('¥', 'utf-8').digest('hex')