Refactored to feistel class

Util.h

@@ -0,0 +1,78 @@
+#pragma once
+#include <bitset>
+#include <sstream>
+#include "Block.h"
+
+//! Mod-operator that works with negative values
+inline int Mod(int numerator, int denominator)
+{
+    return (denominator + (numerator % denominator)) % denominator;
+}
+
+//! Will perform a wrapping left-bitshift on a bitset
+template <std::size_t T>
+inline std::bitset<T> Shiftl(const std::bitset<T>& bits, std::size_t amount)
+{
+    std::stringstream ss;
+    const std::string bitss = bits.to_string();
+
+    for (std::size_t i = 0; i < bitss.size(); i++)
+        ss << bitss[Mod((i + amount), bitss.size())];
+
+    return std::bitset<T>(ss.str());
+}
+
+//! Will perform a wrapping right-bitshift on a bitset
+template <std::size_t T>
+inline std::bitset<T> Shiftr(const std::bitset<T>& bits, std::size_t amount)
+{
+    std::stringstream ss;
+    const std::string bitss = bits.to_string();
+
+    for (std::size_t i = 0; i < bitss.size(); i++)
+        ss << bitss[Mod((i - amount), bitss.size())];
+
+    return std::bitset<T>(ss.str());
+}
+
+//! Will convert a string to a data block
+inline Block StringToBits(const std::string& s)
+{
+    std::stringstream ss;
+
+    for (std::size_t i = 0; i < s.size(); i++)
+        ss << std::bitset<8>(s[i]);
+
+    // Pad rest with zeores
+    for (std::size_t i = s.size() * 8; i < BLOCK_SIZE; i++)
+        ss << '0';
+
+    return Block(ss.str());
+}
+
+//! Will convert a data block to a string
+inline std::string BitsToString(const Block& bits)
+{
+    std::stringstream ss;
+
+    const std::string bitstring = bits.to_string();
+
+    for (std::size_t i = 0; i < BLOCK_SIZE; i += 8)
+    {
+        ss << (char)std::bitset<8>(bitstring.substr(i, 8)).to_ulong();
+    }
+
+    return ss.str();
+}
+
+//! Creates a key of size key-size from a password of arbitrary length.
+inline Block PasswordToKey(const std::string& in)
+{
+    Block b;
+
+    // Segment the password in segments of key-size, and xor them together.
+    for (std::size_t i = 0; i < in.size(); i += BLOCK_SIZE / 8)
+        b ^= StringToBits(in.substr(i, BLOCK_SIZE / 8));
+
+    return b;
+}