Open-source multiplayer game server compatible with the RuneScape client
https://www.openrs2.org/
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49 lines
1.5 KiB
49 lines
1.5 KiB
package org.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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public const val XTEA_BLOCK_SIZE: Int = 8
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private const val BLOCK_SIZE_MASK = XTEA_BLOCK_SIZE - 1
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public fun ByteBuf.xteaEncrypt(index: Int, length: Int, key: SymmetricKey) {
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val k = key.toIntArray()
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val end = index + (length and BLOCK_SIZE_MASK.inv())
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for (i in index until end step XTEA_BLOCK_SIZE) {
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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 + k[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 + k[(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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public fun ByteBuf.xteaDecrypt(index: Int, length: Int, key: SymmetricKey) {
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val k = key.toIntArray()
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val end = index + (length and BLOCK_SIZE_MASK.inv())
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for (i in index until end step XTEA_BLOCK_SIZE) {
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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 + k[(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 + k[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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