// generateRoundMaterial creates the TMC (TBox + MixColumns) tables.
func generateRoundMaterial(rs *random.Source, out *Construction, hidden func(int, int) table.DoubleToWord) {
for round := 0; round < 10; round++ {
for pos := 0; pos < 16; pos += 2 {
out.TBoxMixCol[round][pos/2] = encoding.DoubleToWordTable{
encoding.NewDoubleLinear(common.MixingBijection(rs, 16, round, pos/2)),
encoding.InverseWord{
encoding.NewWordLinear(common.MixingBijection(rs, 32, round, pos/4)),
},
hidden(round, pos),
}
}
}
}
// generateRoundMaterial creates the TMC (TBox + MixColumns) tables.
func generateRoundMaterial(rs *common.RandomSource, out *Construction, hidden func(int, int) table.DoubleToWord) {
for round := 0; round < 10; round++ {
for pos := 0; pos < 16; pos += 2 {
inEnc := common.MixingBijection(rs, 16, round, pos/2)
outEnc := common.MixingBijection(rs, 32, round, pos/4)
inInv, _ := inEnc.Invert()
outInv, _ := outEnc.Invert()
out.TBoxMixCol[round][pos/2] = encoding.DoubleToWordTable{
encoding.DoubleLinear{inEnc, inInv},
encoding.WordLinear{outInv, outEnc},
hidden(round, pos),
}
}
}
}
func maskSwap(rs *random.Source, size, round int) (out matrix.Matrix) {
out = matrix.GenerateEmpty(128, 128)
for row := 0; row < 128; row += size {
col := row / 8
m := common.MixingBijection(rs, size, round, row/size)
for subRow := 0; subRow < size; subRow++ {
copy(out[row+subRow][col:], m[subRow])
}
}
return
}
// blockMaskEncoding concatenates all the mask encodings for InputMask or TBoxOutputMask into a block encoding, so that
// it can easily be put on the output of one of the Block tables.
//
// position is the index of the Block table and shift is the permutation that will be applied between this round and the
// next or noshift if this is an input encoding; the other parameters are explained in MaskEncoding documentation.
func blockMaskEncoding(rs *random.Source, position int, surface common.Surface, shift func(int) int) encoding.Block {
out := encoding.ConcatenatedBlock{}
for i := 0; i < 16; i++ {
out[i] = encoding.ConcatenatedByte{
maskEncoding(rs, surface)(position, 2*i+0),
maskEncoding(rs, surface)(position, 2*i+1),
}
if surface == common.Inside {
out[i] = encoding.ComposedBytes{
encoding.NewByteLinear(common.MixingBijection(rs, 8, -1, shift(i))),
out[i],
}
}
}
return out
}
func generateKeys(rs *random.Source, opts common.KeyGenerationOpts, out *Construction, inputMask, outputMask *matrix.Matrix, shift func(int) int, skinny func(int) table.Byte, wide func(int, int) table.Word) {
// Generate input and output encodings.
common.GenerateMasks(rs, opts, inputMask, outputMask)
// Generate the Input Mask slices and XOR tables.
for pos := 0; pos < 16; pos++ {
out.InputMask[pos] = encoding.BlockTable{
encoding.IdentityByte{},
blockMaskEncoding(rs, pos, common.Inside, shift),
common.BlockMatrix{Linear: *inputMask, Position: pos},
}
}
out.InputXORTables = common.BlockNibbleXORTables(
maskEncoding(rs, common.Inside),
xorEncoding(rs, 10, common.Inside),
roundEncoding(rs, -1, common.Outside, shift),
)
// Generate round material.
for round := 0; round < 9; round++ {
for pos := 0; pos < 16; pos++ {
// Generate a word-sized mixing bijection and stick it on the end of the T-Box/Tyi Table.
mb := common.MixingBijection(rs, 32, round, pos/4)
// Build the T-Box and Tyi Table for this round and position in the state matrix.
out.TBoxTyiTable[round][pos] = encoding.WordTable{
encoding.ComposedBytes{
encoding.NewByteLinear(common.MixingBijection(rs, 8, round-1, pos)),
byteRoundEncoding(rs, round-1, pos, common.Outside, common.NoShift),
},
encoding.ComposedWords{
encoding.ConcatenatedWord{
encoding.NewByteLinear(common.MixingBijection(rs, 8, round, shift(pos/4*4+0))),
encoding.NewByteLinear(common.MixingBijection(rs, 8, round, shift(pos/4*4+1))),
encoding.NewByteLinear(common.MixingBijection(rs, 8, round, shift(pos/4*4+2))),
encoding.NewByteLinear(common.MixingBijection(rs, 8, round, shift(pos/4*4+3))),
},
encoding.NewWordLinear(mb),
wordStepEncoding(rs, round, pos, common.Inside),
},
wide(round, pos),
}
// Encode the inverse of the mixing bijection from above in the MB^(-1) table for this round and position.
mbInv, _ := mb.Invert()
out.MBInverseTable[round][pos] = encoding.WordTable{
byteRoundEncoding(rs, round, pos, common.Inside, common.NoShift),
wordStepEncoding(rs, round, pos, common.Outside),
mbInverseTable{mbInv, uint(pos) % 4},
}
}
}
// Generate the High and Low XOR Tables for reach round.
out.HighXORTable = xorTables(rs, common.Inside, common.NoShift)
out.LowXORTable = xorTables(rs, common.Outside, shift)
// Generate the 10th T-Box/Output Mask slices and XOR tables.
for pos := 0; pos < 16; pos++ {
out.TBoxOutputMask[pos] = encoding.BlockTable{
encoding.ComposedBytes{
encoding.NewByteLinear(common.MixingBijection(rs, 8, 8, pos)),
byteRoundEncoding(rs, 8, pos, common.Outside, common.NoShift),
},
blockMaskEncoding(rs, pos, common.Outside, shift),
table.ComposedToBlock{
Heads: skinny(pos),
Tails: common.BlockMatrix{Linear: *outputMask, Position: pos},
},
}
}
out.OutputXORTables = common.BlockNibbleXORTables(
maskEncoding(rs, common.Outside),
xorEncoding(rs, 10, common.Outside),
func(position int) encoding.Nibble { return encoding.IdentityByte{} },
)
}