115 lines
2.2 KiB
C++
115 lines
2.2 KiB
C++
#include "FeistelMan.h"
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#include "Util.h"
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#include <iostream>
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FeistelMan::FeistelMan(const Block& key)
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:
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key { key }
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{
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return;
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}
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FeistelMan::FeistelMan(const std::string& password)
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{
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key = PasswordToKey(password);
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return;
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}
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FeistelMan::~FeistelMan()
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{
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// Clear key memory
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ZeroKeyMemory();
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return;
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}
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void FeistelMan::SetKey(const Block& key)
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{
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ZeroKeyMemory();
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this->key = key;
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return;
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}
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void FeistelMan::SetPassword(const std::string& password)
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{
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ZeroKeyMemory();
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key = PasswordToKey(password);
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return;
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}
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Flexblock FeistelMan::Encipher(const Flexblock& data) const
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{
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// Split cleartext into blocks
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std::vector<Block> blocks;
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for (std::size_t i = 0; i < data.size(); i += BLOCK_SIZE)
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blocks.push_back(Block(
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PadStringToLength(data.substr(i, BLOCK_SIZE), BLOCK_SIZE, '0', false))
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);
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// Encrypt individual blocks using cipher block chaining
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Feistel feistel(key);
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for (std::size_t i = 0; i < blocks.size(); i++)
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{
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const Block& lastBlock = (i>0) ? blocks[i-1] : emptyBlock;
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blocks[i] = feistel.Encipher(blocks[i] ^ lastBlock);
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}
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// Concatenate ciphertext blocks back into a flexblock
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std::stringstream ss;
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for (Block& b : blocks)
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ss << b;
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// Return it
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return ss.str();
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}
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Flexblock FeistelMan::Decipher(const Flexblock& data) const
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{
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// Split ciphertext into blocks
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std::vector<Block> blocks;
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for (std::size_t i = 0; i < data.size(); i += BLOCK_SIZE)
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blocks.push_back(Block(
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PadStringToLength(data.substr(i, BLOCK_SIZE), BLOCK_SIZE, '0', false))
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);
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// Decrypt individual blocks
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Feistel feistel(key);
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// We can't do this in-loop for decryption, because we are decrypting the blocks in-place.
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Block lastBlock = emptyBlock;
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for (std::size_t i = 0; i < blocks.size(); i++)
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{
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Block tmpCopy = blocks[i];
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blocks[i] = feistel.Decipher(blocks[i]) ^ lastBlock;
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lastBlock = std::move(tmpCopy);
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}
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// Concatenate ciphertext blocks back into a flexblock
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std::stringstream ss;
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for (Block& b : blocks)
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ss << b;
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// Return it
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return ss.str();
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}
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#pragma optimize("", off )
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void FeistelMan::ZeroKeyMemory()
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{
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key.reset();
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return;
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}
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#pragma optimize("", on )
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const Block FeistelMan::emptyBlock;
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