67 lines
1.8 KiB
C++
67 lines
1.8 KiB
C++
#ifndef GCRYPT_FEISTEL_H
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#define GCRYPT_FEISTEL_H
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#include "GCrypt/Keyset.h"
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#include "GCrypt/Block.h"
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#include "GCrypt/Key.h"
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namespace Leonetienne::GCrypt {
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/** Class to perform a feistel block chipher
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*/
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class Feistel {
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public:
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explicit Feistel(const Key& key);
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Feistel(const Feistel& other) = delete;
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Feistel(Feistel&& other) noexcept = delete;
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~Feistel();
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//! Will set the seed-key for this feistel network.
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//! Roundkeys will be derived from this.
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void SetKey(const Key& key);
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//! Will encipher a data block via the set seed-key
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Block Encipher(const Block& data);
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//! Will decipher a data block via the set seed-key
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Block Decipher(const Block& data);
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void operator=(const Feistel& other);
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private:
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//! Will run the feistel rounds, with either regular key
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//! order or reversed key order
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Block Run(const Block& data, bool modeEncrypt);
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//! Arbitrary cipher function
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static Halfblock F(Halfblock m, const Key& key);
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//! Split a data block into two half blocks (into L and R)
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static std::pair<Halfblock, Halfblock> FeistelSplit(const Block& block);
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//! Combine two half blocks (L and R) into a regular data block
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static Block FeistelCombine(const Halfblock& l, const Halfblock& r);
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//! Will expand a halfblock to a fullblock
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static Block ExpansionFunction(const Halfblock& block);
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//! Will reduce a fullblock to a halfblock
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static Halfblock ReductionFunction(const Block& block);
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//! Substitutes eight bits by static random others, inplace
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static void SBox(Block& block);
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//! Will generate a the round keys
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void GenerateRoundKeys(const Key& seedKey);
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//! Will zero the memory used by the keyset
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void ZeroKeyMemory();
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Keyset roundKeys;
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};
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}
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#endif
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