@Override
	public Callback[] getAuthenticationCallbacks() {
		SignatureCallback sigCb;
		try {
			byte[] token = TokenGenerator.getNewToken(TOKEN_SIZE);
			boolean usingSelfSignedCert =
				ApplicationKeyManagerFactory.usingGeneratedSelfSignedCertificate();
			SignedToken signedToken = ApplicationKeyManagerUtils.getSignedToken(
				usingSelfSignedCert ? null : authorities, token);
			sigCb = new SignatureCallback(authorities, token, signedToken.signature);
		}
		catch (Throwable t) {
			throw new RuntimeException("Unable to generate signed token", t);
		}
		return new Callback[] { sigCb };
	}
<code>PKIAuthenticationModule</code> performs client authentication through the 
use of a dual-signed token.
Ghidra/Features/GhidraServer/src/main/java/ghidra/server/security/PKIAuthenticationModule.java