message: fixed a bug in generateSendableData of BigIntegerCiphertext.
diff: @@ -225,7 +225,8 @@ public:
  //Since BigIntegerCiphertext is both an AsymmetricCiphertext and a AsymmetricCiphertextSendableData, on the one hand it has to implement
  //the generateSendableData() function, but on the other hand it is in itself an AsymmetricCiphertextSendableData, so we do not really
  //generate sendable data, but just return this object.
  - return shared_ptr<AsymmetricCiphertextSendableData>(this);
  + //In order to avoid double deletion, we tell the pointer to use empty destructor.
  + return shared_ptr<AsymmetricCiphertextSendableData>(this, [](void*){});
  }
  bool operator==(const AsymmetricCiphertext &other) const {
  