docs: public String encryptKey(SecretKey key, PublicKey destinationPublicKey) {
  
          // Basic null check
          if (key == null) {
              return null;
          }
  
          // Convert the input key to a byte array:
          byte[] bytes = key.getEncoded();
  
          // Encrypt the bytes:
          byte[] encrypted;
          try {
              Cipher cipher = getCipher(destinationPublicKey);
              encrypted = cipher.doFinal(bytes);
          } catch (IllegalBlockSizeException e) {
              throw new IllegalArgumentException("Error encrypting SecretKey: " + IllegalBlockSizeException.class.getSimpleName(), e);
          } catch (BadPaddingException e) {
              throw new IllegalArgumentException("Error encrypting SecretKey: " + BadPaddingException.class.getSimpleName(), e);
          }
  
          return ByteArray.toBase64(encrypted);
      }