crypto: getDecoder throws "AssertionError: Cannot change encoding" when encoding is "ucs2", "ucs-2" or "utf-16le".

[atstoyanov]

• v6.3.0:
• Windows 64-bit:

I've got similar issue as:
#5655
when I'm using as output encoding 'ucs2', 'usc-2' or 'utf-16le'. If I'm using 'utf16le' the code works.

Here is the not working code:
var decrypted = decipher.update(value, 'base64', 'usc2');

Output:

Stack: AssertionError: Cannot change encoding at getDecoder (crypto.js:105:3) at Decipheriv.Cipher.update (crypto.js:146:21)

and here the working one:
var decrypted = decipher.update(value, 'base64', 'utf16le');

According to the documentation:

The output_encoding specifies the output format of the enciphered data, and can be 'latin1', 'ascii' or 'utf8'.

the utf16le is not supported as output encoding, but it works if you specify 'utf16le'.

The change in lib/crypto.js fix the issue with utf-8, but not with utf-16le.
There is a function 'normalizeEncoding' in lib/internal/util.js that can be used to normalize the encoding.

[addaleax]

There is a function 'normalizeEncoding' nn lib/internal/util.js that can be used to normalize the encoding.

Sounds like you can submit a pull request with that, if you like? There’s some info in https://github.com/nodejs/node/blob/master/CONTRIBUTING.md on how to do that.

[jasnell]

@atstojanov ... are you interested in writing up a pull request for this?

[atstoyanov]

@jasnell yes, I'm.