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// Reference: https://eprint.iacr.org/2015/267.pdf (1 out of 2 OT case)
// Sender has 2 messages m0, m1
// Receiver receives mc based on the choice bit c
package simot
import (
"bytes"
"crypto/rand"
"testing"
"github.com/cloudflare/circl/group"
)
const testSimOTCount = 100
func simOT(myGroup group.Group, sender *Sender, receiver *Receiver, m0, m1 []byte, choice, index int) error {
// Initialization
A := sender.InitSender(myGroup, m0, m1, index)
// Round 1
// Sender sends A to receiver
B := receiver.Round1Receiver(myGroup, choice, index, A)
// Round 2
// Receiver sends B to sender
e0, e1 := sender.Round2Sender(B)
// Round 3
// Sender sends e0 e1 to receiver
errDec := receiver.Round3Receiver(e0, e1, receiver.c)
if errDec != nil {
return errDec
}
return nil
}
func testNegativeSimOT(t *testing.T, myGroup group.Group, choice int) {
var sender Sender
var receiver Receiver
m0 := make([]byte, myGroup.Params().ScalarLength)
m1 := make([]byte, myGroup.Params().ScalarLength)
_, errRand := rand.Read(m0)
if errRand != nil {
panic(errRand)
}
_, errRand = rand.Read(m1)
if errRand != nil {
panic(errRand)
}
// Initialization
A := sender.InitSender(myGroup, m0, m1, 0)
// Round 1
B := receiver.Round1Receiver(myGroup, choice, 0, A)
// Round 2
e0, e1 := sender.Round2Sender(B)
// Round 3
// Here we pass in the flipped choice bit, to prove the decryption will fail
// The receiver will not learn anything about m_{1-c}
errDec := receiver.Round3Receiver(e0, e1, 1-choice)
if errDec == nil {
t.Error("SimOT decryption failed", errDec)
}
if choice == 0 {
equal0 := bytes.Compare(sender.m0, receiver.mc)
if equal0 == 0 {
t.Error("Receiver decryption should fail")
}
equal1 := bytes.Compare(sender.m1, receiver.mc)
if equal1 == 0 {
t.Error("Receiver decryption should fail")
}
} else {
equal0 := bytes.Compare(sender.m0, receiver.mc)
if equal0 == 0 {
t.Error("Receiver decryption should fail")
}
equal1 := bytes.Compare(sender.m1, receiver.mc)
if equal1 == 0 {
t.Error("Receiver decryption should fail")
}
}
}
// Input: myGroup, the group we operate in
func testSimOT(t *testing.T, myGroup group.Group, choice int) {
var sender Sender
var receiver Receiver
m0 := make([]byte, myGroup.Params().ScalarLength)
m1 := make([]byte, myGroup.Params().ScalarLength)
_, errRand := rand.Read(m0)
if errRand != nil {
panic(errRand)
}
_, errRand = rand.Read(m1)
if errRand != nil {
panic(errRand)
}
errDec := simOT(myGroup, &sender, &receiver, m0, m1, choice, 0)
if errDec != nil {
t.Error("AES GCM Decryption failed")
}
if choice == 0 {
equal0 := bytes.Compare(sender.m0, receiver.mc)
if equal0 != 0 {
t.Error("Receiver decryption failed")
}
} else {
equal1 := bytes.Compare(sender.m1, receiver.mc)
if equal1 != 0 {
t.Error("Receiver decryption failed")
}
}
}
func benchmarSimOT(b *testing.B, myGroup group.Group) {
var sender Sender
var receiver Receiver
m0 := make([]byte, myGroup.Params().ScalarLength)
m1 := make([]byte, myGroup.Params().ScalarLength)
_, errRand := rand.Read(m0)
if errRand != nil {
panic(errRand)
}
_, errRand = rand.Read(m1)
if errRand != nil {
panic(errRand)
}
for iter := 0; iter < b.N; iter++ {
errDec := simOT(myGroup, &sender, &receiver, m0, m1, iter%2, 0)
if errDec != nil {
b.Error("AES GCM Decryption failed")
}
}
}
func benchmarkSimOTRound(b *testing.B, myGroup group.Group) {
var sender Sender
var receiver Receiver
m0 := make([]byte, myGroup.Params().ScalarLength)
m1 := make([]byte, myGroup.Params().ScalarLength)
_, errRand := rand.Read(m0)
if errRand != nil {
panic(errRand)
}
_, errRand = rand.Read(m1)
if errRand != nil {
panic(errRand)
}
b.Run("Sender-Initialization", func(b *testing.B) {
for i := 0; i < b.N; i++ {
sender.InitSender(myGroup, m0, m1, 0)
}
})
A := sender.InitSender(myGroup, m0, m1, 0)
b.Run("Receiver-Round1", func(b *testing.B) {
for i := 0; i < b.N; i++ {
receiver.Round1Receiver(myGroup, 0, 0, A)
}
})
B := receiver.Round1Receiver(myGroup, 0, 0, A)
b.Run("Sender-Round2", func(b *testing.B) {
for i := 0; i < b.N; i++ {
sender.Round2Sender(B)
}
})
e0, e1 := sender.Round2Sender(B)
b.Run("Receiver-Round3", func(b *testing.B) {
for i := 0; i < b.N; i++ {
errDec := receiver.Round3Receiver(e0, e1, receiver.c)
if errDec != nil {
b.Error("Receiver-Round3 decryption failed")
}
}
})
errDec := receiver.Round3Receiver(e0, e1, receiver.c)
if errDec != nil {
b.Error("Receiver-Round3 decryption failed")
}
// Confirm
equal0 := bytes.Compare(sender.m0, receiver.mc)
if equal0 != 0 {
b.Error("Receiver decryption failed")
}
}
func TestSimOT(t *testing.T) {
t.Run("SimOT", func(t *testing.T) {
for i := 0; i < testSimOTCount; i++ {
currGroup := group.P256
choice := i % 2
testSimOT(t, currGroup, choice)
}
})
t.Run("SimOTNegative", func(t *testing.T) {
for i := 0; i < testSimOTCount; i++ {
currGroup := group.P256
choice := i % 2
testNegativeSimOT(t, currGroup, choice)
}
})
}
func BenchmarkSimOT(b *testing.B) {
currGroup := group.P256
benchmarSimOT(b, currGroup)
}
func BenchmarkSimOTRound(b *testing.B) {
currGroup := group.P256
benchmarkSimOTRound(b, currGroup)
}
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