Open-source multiplayer game server compatible with the RuneScape client
https://www.openrs2.org/
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45 lines
1.2 KiB
45 lines
1.2 KiB
package dev.openrs2.crypto
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import io.netty.buffer.ByteBuf
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private const val GOLDEN_RATIO = 0x9e3779b9.toInt()
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private const val ROUNDS = 32
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fun ByteBuf.xteaEncrypt(index: Int, length: Int, key: IntArray) {
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require(key.size == 4)
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for (i in index until index + length step 8) {
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var sum = 0
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var v0 = getInt(i)
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var v1 = getInt(i + 4)
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for (j in 0 until ROUNDS) {
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v0 += (((v1 shl 4) xor (v1 ushr 5)) + v1) xor (sum + key[sum and 3])
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sum += GOLDEN_RATIO
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v1 += (((v0 shl 4) xor (v0 ushr 5)) + v0) xor (sum + key[(sum ushr 11) and 3])
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}
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setInt(i, v0)
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setInt(i + 4, v1)
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}
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}
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fun ByteBuf.xteaDecrypt(index: Int, length: Int, key: IntArray) {
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require(key.size == 4)
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for (i in index until index + length step 8) {
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@Suppress("INTEGER_OVERFLOW")
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var sum = GOLDEN_RATIO * ROUNDS
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var v0 = getInt(i)
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var v1 = getInt(i + 4)
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for (j in 0 until ROUNDS) {
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v1 -= (((v0 shl 4) xor (v0 ushr 5)) + v0) xor (sum + key[(sum ushr 11) and 3])
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sum -= GOLDEN_RATIO
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v0 -= (((v1 shl 4) xor (v1 ushr 5)) + v1) xor (sum + key[sum and 3])
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}
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setInt(i, v0)
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setInt(i + 4, v1)
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}
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}
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