39 lines
1.6 KiB
TypeScript
39 lines
1.6 KiB
TypeScript
import { galoisMultiplyBy2 } from './mixColumns'
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const galoisMultiplyBy9 = (value: number): number => {
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return galoisMultiplyBy2(galoisMultiplyBy2(galoisMultiplyBy2(value))) ^ value
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}
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const galoisMultiplyBy11 = (value: number): number => {
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return galoisMultiplyBy2(galoisMultiplyBy2(galoisMultiplyBy2(value)) ^ value) ^ value
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}
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const galoisMultiplyBy13 = (value: number): number => {
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return galoisMultiplyBy2(galoisMultiplyBy2(galoisMultiplyBy2(value) ^ value)) ^ value
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}
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const galoisMultiplyBy14 = (value: number): number => {
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return galoisMultiplyBy2(galoisMultiplyBy2(galoisMultiplyBy2(value) ^ value) ^ value)
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}
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const clampToByte = (value: number): number => {
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return value & 0xFF
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}
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export const invMixColumns = (state: number[][]): number[][] => {
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const result: number[][] = [
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[0, 0, 0, 0],
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[0, 0, 0, 0],
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[0, 0, 0, 0],
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[0, 0, 0, 0]
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]
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for (let col = 0; col < 4; col++) {
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result[0][col] = clampToByte(galoisMultiplyBy14(state[0][col]) ^ galoisMultiplyBy11(state[1][col]) ^ galoisMultiplyBy13(state[2][col]) ^ galoisMultiplyBy9(state[3][col]))
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result[1][col] = clampToByte(galoisMultiplyBy9(state[0][col]) ^ galoisMultiplyBy14(state[1][col]) ^ galoisMultiplyBy11(state[2][col]) ^ galoisMultiplyBy13(state[3][col]))
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result[2][col] = clampToByte(galoisMultiplyBy13(state[0][col]) ^ galoisMultiplyBy9(state[1][col]) ^ galoisMultiplyBy14(state[2][col]) ^ galoisMultiplyBy11(state[3][col]))
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result[3][col] = clampToByte(galoisMultiplyBy11(state[0][col]) ^ galoisMultiplyBy13(state[1][col]) ^ galoisMultiplyBy9(state[2][col]) ^ galoisMultiplyBy14(state[3][col]))
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}
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return result
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} |