public UInt64 Encrypt(UInt64 plainText, UInt32[] subKeys)
{
UInt32 leftHalf = Feal4Helper.GetLeftHalf(plainText);
UInt32 rightHalf = Feal4Helper.GetRightHalf(plainText);
leftHalf ^= subKeys[4];
rightHalf ^= subKeys[5];
var round2Left = leftHalf ^ rightHalf;
var round2Right = leftHalf ^ Feal4Helper.Fbox(round2Left ^ subKeys[0]);
var round3Left = round2Right;
var round3Right = round2Left ^ Feal4Helper.Fbox(round2Right ^ subKeys[1]);
var round4Left = round3Right;
var round4Right = round3Left ^ Feal4Helper.Fbox(round3Right ^ subKeys[2]);
var cipherLeft = round4Left ^ Feal4Helper.Fbox(round4Right ^ subKeys[3]);
var cipherRight = cipherLeft ^ round4Right;
return(Feal4Helper.Combine32BitHalfs(cipherLeft, cipherRight));
}
public UInt64 Decrypt(UInt64 cipherText, UInt32[] subKeys)
{
var cipherSplittedIntoHalfs = Split64BitToHalfs(cipherText);
var cipherLeft = cipherSplittedIntoHalfs[0];
var cipherRight = cipherSplittedIntoHalfs[1];
var round4Right = cipherLeft ^ cipherRight;
var round4Left = cipherLeft ^ Feal4Helper.Fbox(round4Right ^ subKeys[3]);
var round3Right = round4Left;
var round3Left = round4Right ^ Feal4Helper.Fbox(round3Right ^ subKeys[2]);
var round2Right = round3Left;
var round2Left = round3Right ^ Feal4Helper.Fbox(round2Right ^ subKeys[1]);
var leftHalf = round2Right ^ Feal4Helper.Fbox(round2Left ^ subKeys[0]);
var rightHalf = round2Left ^ leftHalf;
leftHalf ^= subKeys[4];
rightHalf ^= subKeys[5];
return((leftHalf << 32) | rightHalf);
}