HarmonyOS RSA算法如何使用

public static String sign(String content, String privateKey, String charset) throws Exception { 
  PKCS8EncodedKeySpec priPKCS8 = new PKCS8EncodedKeySpec(Base64Util.decode(privateKey)); 
  PrivateKey priKey = KeyFactory.getInstance("RSA").generatePrivate(priPKCS8); 
  Signature signature = Signature.getInstance("SHA1WithRSA"); 
  signature.initSign(priKey); 
  signature.update(content.getBytes(charset)); 
  return Base64Util.encodeToString(signature.sign()); 
}