Question about PutSharedIN/OUTGate

[Moriarty002]

How to use these two function
I try to use them in my way like below

if(role == SERVER){
            server=bc->PutINGate(a_int,bitlen,SERVER);
            client=bc->PutDummyINGate(bitlen);
}
else if(role == CLIENT){
            client=bc->PutINGate(a_int,bitlen,CLIENT);
            server=bc->PutDummyINGate(bitlen);
}
out[0]=bc-> PutSharedOUTGate(server);
party->ExecCircuit();
party->Reset();
share *s;
s=out[0]->get_wire_ids_as_share (bc->PutSharedINGate(result[0]));
out[1]=bc->PutOUTGate(s,ALL);
party->ExecCircuit();

I expect that the out[1] is same as server input , but the output of out[1] is 0
I want to know how to use PutSharedIN/OUT correctly

[dd23]

Can you explain what this line is supposed to do?
s=out[0]->get_wire_ids_as_share (bc->PutSharedINGate(result[0]));

[Moriarty002]

Because PutSharedINGate return "gate id" , and what I want is an 'share' object
This line is supposed to get the share* and assign it to 's' .
Did it wrong ?

[dd23]

There is a version of PutSharedINGate that returns a share*, which is probably what you want.
Have a look at §3.1.2 in the developer guide.

[aben20807]

Hi @Moriarty002

I think you just slightly misunderstood the functions.

Following is an example for PutSharedOUTGate and PutSharedINGate

    uint32_t a_int = 3;
    uint32_t b_int = 4;

    share* s_a;
    share* s_b;
    share* s_c;
    // Input
    if(role == SERVER){
        s_a = bc->PutINGate(a_int, bitlen, SERVER);
        s_b = bc->PutDummyINGate(bitlen);
    }
    else if(role == CLIENT){
        s_a = bc->PutDummyINGate(bitlen);
        s_b = bc->PutINGate(b_int, bitlen, CLIENT);
    }
    s_c = bc->PutADDGate(s_a, s_b);
    share* out = bc->PutSharedOUTGate(s_c);

    // Execute and get shared output
    party->ExecCircuit();
    uint32_t c_int_shared = out->get_clear_value<uint32_t>();
    std::cout << (role == SERVER?"server: ":"client: ") << c_int_shared << std::endl; // here output the shared value.
    party->Reset(); // Reset after getting the output value

    // Put shared value as input
    out = bc->PutSharedINGate(c_int_shared, bitlen);
    out = bc->PutOUTGate(out, ALL);

    // Execute agagin and get the reconstructed result
    party->ExecCircuit();
    uint32_t c_int = out->get_clear_value<uint32_t>();
    std::cout << "Result: " << c_int << std::endl; // here output the reconstructed value 7, the result of 3+4.
    party->Reset();

[Moriarty002]

Thanks very much .
All problem are cleared

[L-coder148]

Hello,sorry to bother you @dd23 @aben20807 , would you please take a look at my code, it does not output as expected.
Suppose x1 and x2 are two shares of x, y1 and y2 are two shares of y, and Client holds x1 and y1,Server holds x2 and y2, it satisfies x1+x2=x, y1+y2=y. Now I want to compute x*y=z, at the end, each party holds a share of z, and output their share respectively. For example, Client holds z1 and Server holds z2, such that z1+z2=z, I could not find any problem, but it does not output the expected number , I use ARITH citcuit to compute.

    uint32_t x1 = 1, x2 = 3, y1 = 2, y2 = 4;
    share* x1_shared,*x2_shared,*y1_shared,*y2_shared;
    //x1+x2=x
    x1_shared = addcirc->PutSharedINGate(x1, bitlen);
    x2_shared = addcirc->PutSharedINGate(x2, bitlen);
    y1_shared = addcirc->PutSharedINGate(y1, bitlen);
    y2_shared = addcirc->PutSharedINGate(y2, bitlen);

    share *s_z1, *s_z2, *s_z;
    s_z1 = addcirc->PutADDGate(x1_shared, x2_shared);
    s_z2 = addcirc->PutADDGate(y1_shared, y2_shared);
    s_z = addcirc->PutMULGate(s_z1, s_z2);
    s_z = addcirc->PutSharedOUTGate(s_z);

    party->ExecCircuit();

    uint32_t output = s_z->get_clear_value<uint32_t>();

    if (role == 1)
        std::cout << "client:" << output << std::endl;
    else
        std::cout << "server:" << output << std::endl;
    std::cout << (x1 + x2) * (y1 + y2) << std::endl;

the result is as follows

Hope for your guidance.

[L-coder148]

solved