RosettaCodeData/Task/The-ISAAC-Cipher/Go/the-isaac-cipher.go
2015-02-20 09:02:09 -05:00

119 lines
2.3 KiB
Go

package main
import "fmt"
const (
msg = "a Top Secret secret"
key = "this is my secret key"
)
func main() {
var z state
z.seed(key)
fmt.Println("Message: ", msg)
fmt.Println("Key : ", key)
fmt.Println("XOR : ", z.vernam(msg))
}
type state struct {
aa, bb, cc uint32
mm [256]uint32
randrsl [256]uint32
randcnt int
}
func (z *state) isaac() {
z.cc++
z.bb += z.cc
for i, x := range z.mm {
switch i % 4 {
case 0:
z.aa = z.aa ^ z.aa<<13
case 1:
z.aa = z.aa ^ z.aa>>6
case 2:
z.aa = z.aa ^ z.aa<<2
case 3:
z.aa = z.aa ^ z.aa>>16
}
z.aa += z.mm[(i+128)%256]
y := z.mm[x>>2%256] + z.aa + z.bb
z.mm[i] = y
z.bb = z.mm[y>>10%256] + x
z.randrsl[i] = z.bb
}
}
func (z *state) randInit() {
const gold = uint32(0x9e3779b9)
a := [8]uint32{gold, gold, gold, gold, gold, gold, gold, gold}
mix1 := func(i int, v uint32) {
a[i] ^= v
a[(i+3)%8] += a[i]
a[(i+1)%8] += a[(i+2)%8]
}
mix := func() {
mix1(0, a[1]<<11)
mix1(1, a[2]>>2)
mix1(2, a[3]<<8)
mix1(3, a[4]>>16)
mix1(4, a[5]<<10)
mix1(5, a[6]>>4)
mix1(6, a[7]<<8)
mix1(7, a[0]>>9)
}
for i := 0; i < 4; i++ {
mix()
}
for i := 0; i < 256; i += 8 {
for j, rj := range z.randrsl[i : i+8] {
a[j] += rj
}
mix()
for j, aj := range a {
z.mm[i+j] = aj
}
}
for i := 0; i < 256; i += 8 {
for j, mj := range z.mm[i : i+8] {
a[j] += mj
}
mix()
for j, aj := range a {
z.mm[i+j] = aj
}
}
z.isaac()
}
func (z *state) seed(seed string) {
for i, r := range seed {
if i == 256 {
break
}
z.randrsl[i] = uint32(r)
}
z.randInit()
}
func (z *state) random() (r uint32) {
r = z.randrsl[z.randcnt]
z.randcnt++
if z.randcnt == 256 {
z.isaac()
z.randcnt = 0
}
return
}
func (z *state) randA() byte {
return byte(z.random()%95 + 32)
}
func (z *state) vernam(msg string) string {
b := []byte(msg)
for i := range b {
b[i] ^= z.randA()
}
return fmt.Sprintf("%X", b)
}