How to use Node crypto in NestJS to digest binary

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I am trying to port a pre-existing NodeJS project to NestJS.

Rather than using require I am importing the library like so:

import * as crypto from 'crypto';

Most of the code works. However I am having issues with the following line:

const hash_digest   = hash.update(nonce + message).digest('binary');

The issue is "binary" does not appear to be a valid type. And indeed when I click through into the source located at node_modules/@types/node/crypto.d.ts, I see BinaryToTextEncoding = 'base64' | 'hex'; are the only valid types for the digest method.

However, when I read the documentation it states:

hash.digest([encoding])
Calculates the digest of all of the passed data to be hashed. The encoding can be 'hex', 'binary' or 'base64'.

So is this a difference between the "node" and "nestJS" versions of this library or what am I missing?

And if this is not a valid approach, how else to solve this problem? As it stands now, my nonce gets rejected as invalid if I try any of the following:

const hash_digest   = hash.update(nonce + message, 'binary').digest();

const hash_digest   = hash.update(nonce + message).digest();

const hash_digest   = hash.update(nonce + message, 'binary');

hash_digest   = hash.update(nonce + message).digest(<BinaryToTextEncoding>'binary');
cryptojs nestjs node.js
2 Answers

This isn't anything to do with NestJS, a framework on top of NodeJS, and all to do with Typescript, a superset of JavaScript which adds type safety to the development environment. The typescript types for the crypto package for the BinaryToTextEncoding says that you have the ability to pass in a union of strings, meaning one of the following

type BinaryToTextEncoding = 'base64' | 'hex';
type CharacterEncoding = 'utf8' | 'utf-8' | 'utf16le' | 'latin1';
type LegacyCharacterEncoding = 'ascii' | 'binary' | 'ucs2' | 'ucs-2';

type Encoding = BinaryToTextEncoding | CharacterEncoding | LegacyCharacterEncoding;

// Or in simple terms
type Encoding = 'base64' | 'hex' | 'utf8' | 'utf-8' | 'utf16le' | 'latin1' | 'ascii' | 'binary' | 'ucs2' | 'ucs-2';

This is all for Node14, so make sure the version matches that, but it should accept binary as a valid encoding type. What you should probably be doing is using the update(message, encoding) format instead of update(message).digest(encoding) method

Docs for the NodeJS crypto package's update method

Docs for the update method's encoding type

Overall, it looks like a typescript discrepancy. You could probably make an issue and a PR to the DefinitelyTyped repository

user_95761860

The encoding parameter of the update(message, encoding) method is the input encoding, and will not affect the output encoding. The digest method will give you what you need but the output encoding does not match what your API is expecting. What you're looking for is probably

const hash_digest = hash.update(nonce + message).digest().toString('binary');

This will calculate the digest and convert the resulting Buffer to a string using binary encoding.

user_19397110
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