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@asaelko

asaelko/pq.go

Created Jun 26, 2019
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import (
"math/big"
"math/rand"
"time"
)
func SplitPQ(pq *big.Int) (p1, p2 *big.Int) {
value_0 := big.NewInt(0)
value_1 := big.NewInt(1)
value_15 := big.NewInt(15)
value_17 := big.NewInt(17)
rndmax := big.NewInt(0).SetBit(big.NewInt(0), 64, 1)
what := big.NewInt(0).Set(pq)
rnd := rand.New(rand.NewSource(time.Now().UnixNano()))
g := big.NewInt(0)
i := 0
for !(g.Cmp(value_1) == 1 && g.Cmp(what) == -1) {
q := big.NewInt(0).Rand(rnd, rndmax)
q = q.And(q, value_15)
q = q.Add(q, value_17)
q = q.Mod(q, what)
x := big.NewInt(0).Rand(rnd, rndmax)
whatnext := big.NewInt(0).Sub(what, value_1)
x = x.Mod(x, whatnext)
x = x.Add(x, value_1)
y := big.NewInt(0).Set(x)
lim := 1 << (uint(i) + 18)
j := 1
flag := true
for j < lim && flag {
a := big.NewInt(0).Set(x)
b := big.NewInt(0).Set(x)
c := big.NewInt(0).Set(q)
for b.Cmp(value_0) == 1 {
b2 := big.NewInt(0)
if b2.And(b, value_1).Cmp(value_0) == 1 {
c.Add(c, a)
if c.Cmp(what) >= 0 {
c.Sub(c, what)
}
}
a.Add(a, a)
if a.Cmp(what) >= 0 {
a.Sub(a, what)
}
b.Rsh(b, 1)
}
x.Set(c)
z := big.NewInt(0)
if x.Cmp(y) == -1 {
z.Add(what, x)
z.Sub(z, y)
} else {
z.Sub(x, y)
}
g.GCD(nil, nil, z, what)
if (j & (j - 1)) == 0 {
y.Set(x)
}
j = j + 1
if g.Cmp(value_1) != 0 {
flag = false
}
}
i = i + 1
}
p1 = big.NewInt(0).Set(g)
p2 = big.NewInt(0).Div(what, g)
if p1.Cmp(p2) == 1 {
p1, p2 = p2, p1
}
return
}
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