Sign a message

gistfile1.txt

    String getSignature(String jsonBody) throws IOException {
        try (FileInputStream ksFile = new FileInputStream(keyStorePath)) {
            KeyStore ks = KeyStore.getInstance("PKCS12");
            ks.load(ksFile, keyPassword.toCharArray());
            // there may be more than one key in the keystore...here we are picking the 'dev' key
            var pk = ks.getKey("dev", keyPassword.toCharArray());

            Signature ps = Signature.getInstance("SHA256withRSA");

            ps.initSign((PrivateKey) pk);
            ps.update(jsonBody.getBytes(StandardCharsets.UTF_8));
            return Base64.getEncoder().encodeToString(ps.sign());
        } catch (KeyStoreException | SignatureException | NoSuchAlgorithmException |
                 CertificateException | InvalidKeyException | UnrecoverableKeyException e) {
            Log.error("signature generation failed", e);
            throw new RuntimeException("signature failure");
        }
    }