PGP verification of signature with SHA3 algorithm

[Patrick-Harms]

Does anyone know when Bouncy Castle will be providing support for OpenPGP data that has been signed with a SHA3 algorithm? I can get the Bouncy Castle library to sign data using a SHA3 algorithm e.g. SHA3_256. The HashAlgorithmTags file includes the SHA3 algorithms i.e. https://github.com/bcgit/bc-java/blob/main/pg/src/main/java/org/bouncycastle/bcpg/HashAlgorithmTags.java .

But on a verify operation, it accesses the org.bouncycastle.openpgp.operator.jcajce.OperatorHelper#getDigestName method (https://github.com/bcgit/bc-java/blob/main/pg/src/main/java/org/bouncycastle/openpgp/operator/jcajce/OperatorHelper.java). This method doesn't have the SHA3 algorithms, so the operation fails with: throw new PGPException("unknown hash algorithm tag in getDigestName: " + hashAlgorithm);

Strange that BC can sign but not verify.

[dghgit]

Are you able to provide a (non-BC) SHA-3 signed document?

[Patrick-Harms]

I haven't got to that stage of testing with a non-BC SHA-3 signed document as yet. @dghgit what's your line of thinking? It's quite clear from the org.bouncycastle.openpgp.operator.jcajce.OperatorHelper class, that SHA-3 is not supported i.e. from the above source link:

    String getDigestName(
        int hashAlgorithm)
        throws PGPException
    {
        switch (hashAlgorithm)
        {
        case HashAlgorithmTags.SHA1:
            return "SHA-1";
        case HashAlgorithmTags.MD2:
            return "MD2";
        case HashAlgorithmTags.MD5:
            return "MD5";
        case HashAlgorithmTags.RIPEMD160:
            return "RIPEMD160";
        case HashAlgorithmTags.SHA256:
            return "SHA-256";
        case HashAlgorithmTags.SHA384:
            return "SHA-384";
        case HashAlgorithmTags.SHA512:
            return "SHA-512";
        case HashAlgorithmTags.SHA224:
            return "SHA-224";
        case HashAlgorithmTags.TIGER_192:
            return "TIGER";
        default:
            throw new PGPException("unknown hash algorithm tag in getDigestName: " + hashAlgorithm);
        }
    }

The above exception is what my code fails with when it tries to validate the signed data.