43 lines
962 B
Go
43 lines
962 B
Go
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) {
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// Theta
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var c [5]uint64
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for x := range *a {
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c[x] = a[0][x] ^ a[1][x] ^ a[2][x] ^ a[3][x] ^ a[4][x]
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}
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for x := range a[0] {
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x0, x1 := (x+4)%5, (x+1)%5
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a[0][x] ^= c[x0] ^ rotl(c[x1], 1)
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a[1][x] ^= c[x0] ^ rotl(c[x1], 1)
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a[2][x] ^= c[x0] ^ rotl(c[x1], 1)
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a[3][x] ^= c[x0] ^ rotl(c[x1], 1)
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a[4][x] ^= c[x0] ^ rotl(c[x1], 1)
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}
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// Rho and pi
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var b [5][5]uint64
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for y := range *a {
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for x := range a[0] {
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x0 := y
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y0 := (x*2 + y*3) % 5
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b[y0][x0] = rotl(a[y][x], rotc[y][x])
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}
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}
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// Chi
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for y := range a[0] {
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c := [5]uint64{b[y][0], b[y][1], b[y][2], b[y][3], b[y][4]}
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a[y][0] = b[y][0] ^ ^c[1]&c[2]
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a[y][1] = b[y][1] ^ ^c[2]&c[3]
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a[y][2] = b[y][2] ^ ^c[3]&c[4]
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a[y][3] = b[y][3] ^ ^c[4]&c[0]
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a[y][4] = b[y][4] ^ ^c[0]&c[1]
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}
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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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