114 lines
3.4 KiB
Kotlin
114 lines
3.4 KiB
Kotlin
package com.infendro.hash.keccak
|
||
|
||
import com.infendro.bytearray.ByteOrder.LITTLE_ENDIAN
|
||
import com.infendro.bytearray.addAll
|
||
import com.infendro.bytearray.toByteArray
|
||
import com.infendro.bytearray.toULongArray
|
||
import com.infendro.hash.HashFunction
|
||
import kotlin.math.min
|
||
|
||
@Suppress("UNUSED")
|
||
open class Keccak internal constructor(
|
||
override val bytes: Int,
|
||
private val rate: Int,
|
||
private val domain: Byte,
|
||
) : HashFunction() {
|
||
init {
|
||
if (rate % 8 != 0) {
|
||
throw IllegalArgumentException("rate must be divisible by 8")
|
||
}
|
||
}
|
||
|
||
private val rc = ulongArrayOf(
|
||
0x0000000000000001UL, 0x0000000000008082UL, 0x800000000000808aUL, 0x8000000080008000UL,
|
||
0x000000000000808bUL, 0x0000000080000001UL, 0x8000000080008081UL, 0x8000000000008009UL,
|
||
0x000000000000008aUL, 0x0000000000000088UL, 0x0000000080008009UL, 0x000000008000000aUL,
|
||
0x000000008000808bUL, 0x800000000000008bUL, 0x8000000000008089UL, 0x8000000000008003UL,
|
||
0x8000000000008002UL, 0x8000000000000080UL, 0x000000000000800aUL, 0x800000008000000aUL,
|
||
0x8000000080008081UL, 0x8000000000008080UL, 0x0000000080000001UL, 0x8000000080008008UL
|
||
)
|
||
|
||
private val rotation = arrayOf(
|
||
intArrayOf(0, 36, 3, 41, 18),
|
||
intArrayOf(1, 44, 10, 45, 2),
|
||
intArrayOf(62, 6, 43, 15, 61),
|
||
intArrayOf(28, 55, 25, 21, 56),
|
||
intArrayOf(27, 20, 39, 8, 14),
|
||
)
|
||
|
||
override fun hash(
|
||
value: ByteArray,
|
||
): ByteArray {
|
||
val paddedValue = buildList {
|
||
addAll(value)
|
||
add(domain)
|
||
while ((size % rate) != (rate - 1)) {
|
||
add(0x00.toByte())
|
||
}
|
||
add(0x80.toByte())
|
||
}
|
||
|
||
val state = ULongArray(25)
|
||
|
||
// absorb
|
||
val chunks = paddedValue
|
||
.chunked(rate)
|
||
for (chunk in chunks) {
|
||
val numbers = chunk.toULongArray(LITTLE_ENDIAN)
|
||
for ((i, number) in numbers.withIndex()) {
|
||
state[i] = state[i] xor number
|
||
}
|
||
permute(state)
|
||
}
|
||
|
||
// squeeze
|
||
return buildList(bytes) {
|
||
var i = 0
|
||
while (size < bytes) {
|
||
if (i == rate / 8) {
|
||
permute(state)
|
||
i = 0
|
||
}
|
||
addAll(
|
||
state[i++].toByteArray(LITTLE_ENDIAN)
|
||
.take(min(bytes - size, 8))
|
||
)
|
||
}
|
||
}.toByteArray()
|
||
}
|
||
|
||
private fun permute(
|
||
a: ULongArray,
|
||
) {
|
||
val b = ULongArray(25)
|
||
val c = ULongArray(5)
|
||
val d = ULongArray(5)
|
||
|
||
repeat(24) { round ->
|
||
// θ
|
||
for (x in 0..4) {
|
||
c[x] = a[x] xor a[x + 5] xor a[x + 10] xor a[x + 15] xor a[x + 20]
|
||
}
|
||
for (x in 0..4) {
|
||
d[x] = c[(x + 4) % 5] xor c[(x + 1) % 5].rotateLeft(1)
|
||
}
|
||
for (x in 0..4) for (y in 0..4) {
|
||
a[x + 5 * y] = a[x + 5 * y] xor d[x]
|
||
}
|
||
|
||
// ρ and π
|
||
for (x in 0..4) for (y in 0..4) {
|
||
b[y + 5 * ((2 * x + 3 * y) % 5)] = a[x + 5 * y].rotateLeft(rotation[x][y])
|
||
}
|
||
|
||
// χ
|
||
for (x in 0..4) for (y in 0..4) {
|
||
a[x + 5 * y] = b[x + 5 * y] xor ((b[((x + 1) % 5) + 5 * y].inv()) and b[((x + 2) % 5) + 5 * y])
|
||
}
|
||
|
||
// ι
|
||
a[0] = a[0] xor rc[round]
|
||
}
|
||
}
|
||
}
|