71 lines
1.3 KiB
Go
71 lines
1.3 KiB
Go
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package keccak
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// roundGeneric implements one round of the keccak-f[1600] permutation.
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func roundGeneric(a [5][5]uint64) [5][5]uint64 {
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a = theta(a)
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a = rho(a)
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a = pi(a)
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a = chi(a)
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// Iota
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//a[0][0] ^= RC[i]
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return a
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}
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// Theta
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func theta(a [5][5]uint64) [5][5]uint64 {
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var c [5]uint64
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for x := range a {
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c[x] = a[x][0] ^ a[x][1] ^ a[x][2] ^ a[x][3] ^ a[x][4]
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}
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for x := range a {
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x0, x1 := (x+4)%5, (x+1)%5
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a[x][0] ^= c[x0] ^ rotl(c[x1], 1)
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a[x][1] ^= c[x0] ^ rotl(c[x1], 1)
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a[x][2] ^= c[x0] ^ rotl(c[x1], 1)
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a[x][3] ^= c[x0] ^ rotl(c[x1], 1)
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a[x][4] ^= c[x0] ^ rotl(c[x1], 1)
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}
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return a
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}
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// Rho
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func rho(a [5][5]uint64) [5][5]uint64 {
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for x := range a {
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for y := range a[0] {
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a[x][y] = rotl(a[x][y], rotc[x][y])
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}
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}
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return a
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}
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// Pi
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func pi(a [5][5]uint64) [5][5]uint64 {
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var b [5][5]uint64
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for x := range a {
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for y := range a[0] {
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x0 := y
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y0 := (x*2 + y*3) % 5
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b[x0][y0] = a[x][y]
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}
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}
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return b
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}
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// Chi
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func chi(a [5][5]uint64) [5][5]uint64 {
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for y := range a[0] {
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c := [5]uint64{a[0][y], a[1][y], a[2][y], a[3][y], a[4][y]}
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a[0][y] ^= ^c[1] & c[2]
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a[1][y] ^= ^c[2] & c[3]
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a[2][y] ^= ^c[3] & c[4]
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a[3][y] ^= ^c[4] & c[0]
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a[4][y] ^= ^c[0] & c[1]
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}
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return a
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}
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func rotl(a uint64, r uint) uint64 {
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return a<<r | a>>(64-r)
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}
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