How to get md5 of byte array in Node JS?

Question

I have a JAVA piece of code as following :

public static String base64AndMD5(byte[] bytes) throws NoSuchAlgorithmException {
    final MessageDigest md = MessageDigest.getInstance("MD5");
    md.reset();
    md.update(bytes);
    byte[] md5Result = md.digest();
    String base64Result = Base64.encodeBase64String(md5Result);
    return base64Result.length() > 24 ? base64Result.substring(0, 23) : base64Result;
}

I have zero experience with java and most of time work on Node JS. This function expects a byte array and then finds md5 of it and then base64 encodes. I was trying to implement it in NodeJs in the following way:

byteArray = [123, 10, 32, 32, 34, 117, 115, 101, 114, 34, 58, 32, 123, 10, 32, 32, 32, 32, 32, 32, 34, 117, 115, 101, 114, 95, 105, 100, 34, 58, 32, 34, 49, 52, 55, 48, 57, 53, 57, 54, 48, 34, 44, 10, 32, 32, 32, 32, 32, 32, 34, 112, 105, 110, 99, 111, 100, 101, 34, 58, 32, 34, 34, 44, 10, 32, 32, 32, 32, 32, 32, 34, 108, 97, 116, 34, 58, 32, 34, 34, 44, 10, 32, 32, 32, 32, 32, 32, 34, 108, 111, 110, 103, 34, 58, 34, 34, 10, 32, 32, 32, 125, 44, 10, 32, 32, 34, 100, 101, 118, 105, 99, 101, 34, 58, 32, 123, 10, 32, 32, 32, 32, 32, 32, 34, 103, 97, 95, 105, 100, 34, 32, 58, 32, 34, 49, 50, 51, 34, 10, 32, 32, 125, 44, 10, 32, 32, 34, 99, 104, 97, 110, 110, 101, 108, 34, 58, 32, 123, 10, 32, 32, 32, 32, 32, 32, 34, 110, 97, 109, 101, 34, 58, 32, 34, 97, 110, 100, 114, 111, 105, 100, 97, 112, 112, 34, 10, 32, 32, 125, 44, 10, 32, 32, 34, 99, 117, 115, 116, 111, 109, 34, 58, 32, 123, 10, 32, 32, 32, 34, 99, 117, 114, 114, 101, 110, 116, 95, 112, 97, 103, 101, 34, 32, 58, 32, 34, 104, 111, 109, 101, 112, 97, 103, 101, 34, 44, 10, 32, 32, 32, 34, 105, 100, 34, 58, 34, 50, 48, 49, 56, 57, 52, 55, 57, 57, 34, 10, 32, 32, 125, 10, 125];

let md5OfByteArray = crypto.createHash('md5').update(byteArray).digest("hex");

But it returns an error that byteArray should be a string or buffer. Now when I push execute java function with above byte array it returns, hKJQcQlv5e1RB5WyDZX3AA==. Can someone explain what these java functions are doing and how can we do the same in nodejs?

Java encodes the byte array in Base64. So in node you'd have to decode this base64 string into probably an ArrayBuffer — Lino
– Lino, Commented Mar 24, 2020 at 10:42

rels · Accepted Answer · 2020-03-24 11:36:14Z

2

You need to use a buffer based on your bytes array. Then you can hash and encode to base64

function base64AndMD5(bytesArray) {

  const buf = Buffer.from(bytesArray); // bytesArray = [123, 10, 32, 32, 34, 117, 115, 101, 114, 34, 58, 32, 123, 10, 32, 32, 32, 32, 32, 32, 34, 117, 115, 101, 114, 95, 105, 100, 34, 58, 32, 34, 49, 52, 55, 48, 57, 53, 57, 54, 48, 34, 44, 10, 32, 32, 32, 32, 32, 32, 34, 112, 105, 110, 99, 111, 100, 101, 34, 58, 32, 34, 34, 44, 10, 32, 32, 32, 32, 32, 32, 34, 108, 97, 116, 34, 58, 32, 34, 34, 44, 10, 32, 32, 32, 32, 32, 32, 34, 108, 111, 110, 103, 34, 58, 34, 34, 10, 32, 32, 32, 125, 44, 10, 32, 32, 34, 100, 101, 118, 105, 99, 101, 34, 58, 32, 123, 10, 32, 32, 32, 32, 32, 32, 34, 103, 97, 95, 105, 100, 34, 32, 58, 32, 34, 49, 50, 51, 34, 10, 32, 32, 125, 44, 10, 32, 32, 34, 99, 104, 97, 110, 110, 101, 108, 34, 58, 32, 123, 10, 32, 32, 32, 32, 32, 32, 34, 110, 97, 109, 101, 34, 58, 32, 34, 97, 110, 100, 114, 111, 105, 100, 97, 112, 112, 34, 10, 32, 32, 125, 44, 10, 32, 32, 34, 99, 117, 115, 116, 111, 109, 34, 58, 32, 123, 10, 32, 32, 32, 34, 99, 117, 114, 114, 101, 110, 116, 95, 112, 97, 103, 101, 34, 32, 58, 32, 34, 104, 111, 109, 101, 112, 97, 103, 101, 34, 44, 10, 32, 32, 32, 34, 105, 100, 34, 58, 34, 50, 48, 49, 56, 57, 52, 55, 57, 57, 34, 10, 32, 32, 125, 10, 125]

  const hashed = crypto
                       .createHash('md5')
                       .update(buf)
                       .digest("base64"); // hKJQcQlv5e1RB5WyDZX3AA==

  return hashed.length > 24 ? hashed.slice(0, 23) : hashed;
  // this is weird, I would expect hashed.length >= 24 rather than > but anyways it respects your java code.
}

answered Mar 24, 2020 at 11:36

rels

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3 Comments

BEAGLE Over a year ago

Any idea how to do it in plain JS?

rels Over a year ago

you mean in the browser without Node libs?

BEAGLE Over a year ago

Yes. I'm okay using libs via CDN.

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