code: public static String buildSecretFromJwk(final String json) {
          CommonHelper.assertNotBlank("json", json);
  
          try {
              final OctetSequenceKey octetSequenceKey = OctetSequenceKey.parse(json);
              return new String(octetSequenceKey.toByteArray(), "UTF-8");
          } catch (final UnsupportedEncodingException | ParseException e) {
              throw new TechnicalException(e);
          }
      }
docs: Build the secret from the JWK JSON.
  
  @param json the json
  @return the secret