PGPSecretKey sigSecretKey = PGPDataFormatUtil.findSecretKey(exchange.getContext(), sigKeyFileName, sigKeyRing, sigKeyPassword);
if (sigSecretKey == null) {
throw new IllegalArgumentException("Signature secret key is null, cannot proceed");
}
PGPPrivateKey sigPrivateKey = sigSecretKey.extractPrivateKey(new JcePBESecretKeyDecryptorBuilder().setProvider("BC").build(sigKeyPassword.toCharArray()));
if (sigPrivateKey == null) {
throw new IllegalArgumentException("Signature private key is null, cannot proceed");
}
PGPSignatureSubpacketGenerator spGen = new PGPSignatureSubpacketGenerator();