private void TransformText(byte[] text, IBlockCipherEngine engine, int numberOfBlocks, int originalPayloadBitLength)
{
// When the payload meets the block size, do nothing
if (numberOfBlocks == 1 || originalPayloadBitLength % engine.BlockSizeBits == 0)
{
return;
}
// When the text does not match a mod of the block size, swap the final two blocks
for (int i = 0; i < engine.BlockSizeBytes; i++)
{
var secondToLastBlockIndex = (numberOfBlocks - 2) * engine.BlockSizeBytes + i;
var lastBlockIndex = (numberOfBlocks - 1) * engine.BlockSizeBytes + i;
SwapBytesHelper.SwapBytes(text, secondToLastBlockIndex, lastBlockIndex);
}
}
private void TransformText(byte[] text, IBlockCipherEngine engine, int numberOfBlocks, int originalPayloadBitLength)
{
// No blocks to swap when there's only a single block to work with
if (numberOfBlocks == 1)
{
return;
}
// Swap the final two blocks
for (int i = 0; i < engine.BlockSizeBytes; i++)
{
var secondToLastBlockIndex = (numberOfBlocks - 2) * engine.BlockSizeBytes + i;
var lastBlockIndex = (numberOfBlocks - 1) * engine.BlockSizeBytes + i;
SwapBytesHelper.SwapBytes(text, secondToLastBlockIndex, lastBlockIndex);
}
}