docs: public Packer useRSA(final Key rsaKeyForEncrypt, final Key rsaKeyForDecrypt)
  			throws NoSuchAlgorithmException, NoSuchPaddingException {
  		this.rsaCipher = Cipher.getInstance(ASYM_CIPHER_CHAIN_PADDING);
  		this.rsaKeyForEncrypt = rsaKeyForEncrypt;
  		this.rsaKeyForDecrypt = rsaKeyForDecrypt;
  		return this;
  	}