Really the Cuid2 algorithm?

[sdavids]

Describe the bug

I am unsure if this implementation is the same algorithm as the original.

To Reproduce

The entropy is computed differently:

https://github.com/paralleldrive/cuid2/blob/53e246b0919c8123e492e6b6bbab41fe66f4b462/src/index.js#L7-L14

cuid-java/src/main/java/io/github/thibaultmeyer/cuid/CUID.java

Lines 265 to 275 in c55aa79

	private static String createEntropy(final int length) {
	int primeNumber;
	final StringBuilder stringBuilder = new StringBuilder(length);
	while (stringBuilder.length() < length) {
	primeNumber = PRIME_NUMBER_ARRAY[Math.abs(Common.nextIntValue()) % PRIME_NUMBER_ARRAY.length];
	stringBuilder.append(Integer.toString(primeNumber * Common.nextIntValue(), NUMBER_BASE));
	}
	return stringBuilder.toString();

---

The hash is computed differently:

https://github.com/paralleldrive/cuid2/blob/53e246b0919c8123e492e6b6bbab41fe66f4b462/src/index.js#L31-L35

cuid-java/src/main/java/io/github/thibaultmeyer/cuid/CUID.java

Lines 283 to 292 in c55aa79

	private static String computeHash(final String content, final int saltLength) {
	final String salt = createEntropy(saltLength);
	try {
	return new BigInteger(MessageDigest.getInstance("SHA3-256").digest((content + salt).getBytes(StandardCharsets.UTF_8)))
	.toString(NUMBER_BASE);
	} catch (final NoSuchAlgorithmException exception) {
	throw new CUIDGenerationException(exception);
	}
	}

---

The alphabet is accessed differently:

https://github.com/paralleldrive/cuid2/blob/53e246b0919c8123e492e6b6bbab41fe66f4b462/src/index.js#L37-L39

cuid-java/src/main/java/io/github/thibaultmeyer/cuid/CUID.java

Line 69 in c55aa79

final char firstLetter = CUIDv2.ALPHABET_ARRAY[Math.abs(Common.nextIntValue()) % CUIDv2.ALPHABET_ARRAY.length];

https://github.com/ai/nanoid?tab=readme-ov-file

random % alphabet is a popular mistake [...] [t]he distribution will not be even; there will be a lower chance for some symbols to appear compared to others.

[sdavids]

@ericelliott Maybe you could provide an authoritative assessment?

[sdavids]

I opened this issue because I considered doing a 1:1 algorithm translation in a new repo but I think it would be better to update this project instead of creating a new one.

[ericelliott]

Correct that % is not a safe method to generate uniform random values. Are the histogram and randogram tests run in this repo?

[ArnieGA]

Any updates on the issue?