Bouncy Castle Sha3 wrong output?

Question

I'm working on a JAVA project that needs to perform a sha3-256 hash. Since Bouncy Castle implemented Sha3 in its latest update, I plan to use their implementation. Here is my code:

 public static String sha3(final String input) {

    String hash = "";

    final SHA3.DigestSHA3 md = new SHA3.DigestSHA3(256);
    md.update(input.getBytes());
    hash = Main2.toString(md.digest());

    return hash;
  }

When running System.out.println(Main2.sha3(""));, I get the following output:

C5D2460186F7233C927E7DB2DCC703C0E500B653CA82273B7BFAD8045D85A470

When I search fot basic sha3 outputs from: wikipedia: https://en.wikipedia.org/wiki/SHA-3
or NIST standards: http://csrc.nist.gov/groups/ST/toolkit/documents/Examples/SHA3-256_Msg0.pdf , it seems I should obtain:

a7ffc6f8bf1ed76651c14756a061d662f580ff4de43b49fa82d80a4b80f8434a

Is there any mistake in my code? Any link between bouncy castle's output and NIST's? Would there be a mistake in bouncy castle's implementation?

Thanks for your time and regards.

Answer 1

Your SHA3 should be computed correctly.

You have an issue with the code in your question:

• You have not provided Main2.toString(String)

The following hashes and transforms the bytes into a hexadecimal string:

import java.security.MessageDigest;

import org.bouncycastle.jcajce.provider.digest.SHA3.DigestSHA3;
import org.bouncycastle.jcajce.provider.digest.SHA3.Digest256;

public class TestSha3 {
    public static void main(String[] args) {
        System.out.println(sha3(""));
    }

    public static String sha3(final String input) {
        final DigestSHA3 sha3 = new Digest256();

        sha3.update(input.getBytes());

        return TestSha3.hashToString(sha3);
    }

    public static String hashToString(MessageDigest hash) {
        return hashToString(hash.digest());
    }

    public static String hashToString(byte[] hash) {
        StringBuffer buff = new StringBuffer();

        for (byte b : hash) {
            buff.append(String.format("%02x", b & 0xFF));
        }

        return buff.toString();
    }
}

Output

a7ffc6f8bf1ed76651c14756a061d662f580ff4de43b49fa82d80a4b80f8434a

---

I used the following artifact in my Maven build

<dependency>
    <groupId>org.bouncycastle</groupId>
    <artifactId>bcprov-jdk15on</artifactId>
    <version>1.53</version>
</dependency>