Question: Error when Serialization of ciphertext

[guiming-shi]

Hello. I want to serialize ciphertext into xx.bin and deserialize them into the ciphertext, but some errors are printed. Thanks.

panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0x734507]

The error is at : o_ct.UnmarshalBinary(data);

My test function is:

func serialize_ct(ct []*rlwe.Ciphertext) []*rlwe.Ciphertext {
	var o_cts []*rlwe.Ciphertext
	var o_ct *rlwe.Ciphertext

	for i := 0; i < len(ct); i++ {
		if data, eff := ct[i].MarshalBinary(); eff != nil {
			panic(eff)
		} else {
			os.WriteFile("ct"+fmt.Sprint(i)+".bin", data, 0644)
		}
	}

	for i := 0; i < len(ct); i++ {
		data, _ := os.ReadFile("ct" + fmt.Sprint(i) + ".bin")
		if err := o_ct.UnmarshalBinary(data); err != nil {
			panic(err)
		} else {
			o_cts = append(o_cts, o_ct)
		}
	}
	return o_cts
}

[Pro7ech]

There are two issues with your code, and it is not related to the library: o_ct is nil when you unmarshal the data on it, hence your error. Secondly, if you do not re-declare it inside the loop, it will overwrite the underlying ciphertext it since it is a pointer to a ciphertext.

[Pro7ech]

Additionally, Lattigo provides marshalling of ciphertext vectors in utils/structs

[guiming-shi]

Thanks for your answer. It is work!!!