My Mac fails because NETWORK_BUFFER_SIZE not sufficient for sha256 in emp-m2pc

[weikengchen]

OK:) this is not an easy debug. I found the reason why my Mac always fails for sha256 in emp-m2pc due to res4=1 and Alice cheat=1, showing WRONG_ANS.

It seems that my Mac has a terrible loopback network (or I guess too fast?). The standard NETWORK_BUFFER_SIZE in emp_tool/utils/constants.h will make buffer insufficient and cause data loss -- the result is that Bob 'cheats' and the result for sha256 in emp-m2pc is wrong in my specific case.

My question is:
During the EUROCRYPT'17 paper and previous works on emp-toolkit, will a very high NETWORK_BUFFER_SIZE obviously hurts the performance (due to the loss of locality?)? If this performance change is not obvious, maybe the default value for NETWORK_BUFFER_SIZE in emp-tool/utils/constants.h can be changed to a larger one.

(I see the comment nearby said that this value should be adjusted for the specific network. I feel that this value should increase for emp-m2pc because the evaluation is slower, the network can be too fast.)

[weikengchen]

And Thanks to Xiao Wang!

[weikengchen]

An alternative way is to give a boosting for emp-m2pc on NETWORK_BUFFER_SIZE?

Note that the value of NETWORK_BUFFER_SIZE would be hardcoded into the binary of emp-tool.

[wangxiao1254]

I believe that buffer size only affects performance but not correctness. I will explain more when I have time later.

…

On Sat, Oct 28, 2017 at 8:08 PM, Weikeng Chen ***@***.***> wrote: An alternative way is to give a boosting for emp-m2pc on NETWORK_BUFFER_SIZE? Note that the value of NETWORK_BUFFER_SIZE would be hardcoded into the binary of emp-tool. — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#7 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/ACKjCh_honwD-SRH5kbia5D_D4Y3PUHeks5sw8ITgaJpZM4QKIzq> .

[weikengchen]

will double check

[weikengchen]

The real reason found. will send a PR.

[weikengchen]

emp-toolkit/emp-tool#34

[weikengchen]

It turns out that my Mac adopts boost. I will submit another PR to let Mac use socket.