different hash between Node.js crypto-js MD5 and Golang crypto/md5.Sum()

Question

how are objects treated by crypto-js' MD5-function (https://www.npmjs.com/package/crypto-js)? I am trying to replicate the hashing behaviour in Golang using the crypto/md5 (https://pkg.go.dev/crypto/md5) package, but I can't figure out why the hashes are different for my two implementations. It must be something with how crypto-js is treating objects internally, because for pure strings I am getting the same hashes.

Node.js example:

var CryptoJS = require("crypto-js");
let body = {"key":"value"}
let bodyHash =  CryptoJS.MD5(body);
CryptoJS.enc.Base64.stringify(hash)

Outputs the hash: SH97IvaDEtLBu8k7GupEWw==

Golang example:

import (
    "crypto/md5"
    "encoding/base64"
)

type KeyValue struct {
    Key string  `json:"key"`
}

func main() {
    body := KeyValue{
        Key: "value",
    }
    bodyByteArray, _ := json.Marshal(body)
    bodyHash := md5.Sum(bodyByteArray)
    bodyHashBase64 := base64.StdEncoding.EncodeToString(bodyHash)
}

Outputs the hash: pzU/fN3OgI3gAydHoLe+UA==

Any help and explanations are appreciated!

Answer 1

You are using md5 on an object not a string (you are hashing different things)

var CryptoJS = require("crypto-js");
let body = {"key":"value"}
let bodyHash =  CryptoJS.MD5(JSON.stringify(body)); <<<<<<<<<
CryptoJS.enc.Base64.stringify(hash)

Hash: pzU/fN3OgI3gAydHoLe+UA==

For golang

package main

import (
    "crypto/md5"
    "encoding/base64"
    "encoding/json"
    "fmt"
)

type KeyValue struct {
    Key string `json:"key"`
}

func main() {
    body := KeyValue{
        Key: "value",
    }
    bodyByteArray, _ := json.Marshal(body)
    fmt.Println(string(bodyByteArray))
    digest := md5.New()
    digest.Write(bodyByteArray)
    bodyHash := digest.Sum(nil)
    bodyHashBase64 := base64.StdEncoding.EncodeToString(bodyHash)
    fmt.Println(bodyHashBase64)
}

Hash: pzU/fN3OgI3gAydHoLe+UA==