GCrypt/INCLUDE/GhettoCrypt.cpp
2022-02-06 23:00:34 +01:00

550 lines
16 KiB
C++

/*
* BSD 2-Clause License
*
* Copyright (c) 2021, Leon Etienne
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "GhettoCrypt.h"
/*** ./../GhettoCrypt/Cipher.cpp ***/
#include <iostream>
#include <vector>
GhettoCipher::Cipher::Cipher(const Block& key)
:
key { key },
initializationVector(InitializationVector(key))
{
return;
}
GhettoCipher::Cipher::Cipher(const std::string& password)
:
key { PasswordToKey(password) },
initializationVector(InitializationVector(key))
{
return;
}
GhettoCipher::Cipher::~Cipher()
{
// Clear key memory
ZeroKeyMemory();
return;
}
void GhettoCipher::Cipher::SetKey(const Block& key)
{
ZeroKeyMemory();
this->key = key;
return;
}
void GhettoCipher::Cipher::SetPassword(const std::string& password)
{
ZeroKeyMemory();
key = PasswordToKey(password);
return;
}
GhettoCipher::Flexblock GhettoCipher::Cipher::Encipher(const Flexblock& data, bool printProgress) const
{
// Split cleartext into blocks
std::vector<Block> blocks;
for (std::size_t i = 0; i < data.size(); i += BLOCK_SIZE)
blocks.push_back(Block(
PadStringToLength(data.substr(i, BLOCK_SIZE), BLOCK_SIZE, '0', false))
);
// Encrypt individual blocks using cipher block chaining
Feistel feistel(key);
for (std::size_t i = 0; i < blocks.size(); i++)
{
// Print reports if desired. If we have > 1000 blocks, print one report every 100 blocks. Otherwise for every 10th block.
if ((i % ((blocks.size() > 1000)? 100 : 10) == 0) && (printProgress))
std::cout << "Encrypting... (Block " << i << " / " << blocks.size() << " - " << ((float)i*100 / blocks.size()) << "%)" << std::endl;
const Block& lastBlock = (i>0) ? blocks[i-1] : initializationVector;
blocks[i] = feistel.Encipher(blocks[i] ^ lastBlock); // Xor last cipher block with new clear text block before E()
}
// Concatenate ciphertext blocks back into a flexblock
std::stringstream ss;
for (Block& b : blocks)
ss << b;
// Return it
return ss.str();
}
GhettoCipher::Flexblock GhettoCipher::Cipher::Decipher(const Flexblock& data, bool printProgress) const
{
// Split ciphertext into blocks
std::vector<Block> blocks;
for (std::size_t i = 0; i < data.size(); i += BLOCK_SIZE)
blocks.push_back(Block(
PadStringToLength(data.substr(i, BLOCK_SIZE), BLOCK_SIZE, '0', false))
);
// Decrypt individual blocks
Feistel feistel(key);
// We can't do this in-loop for decryption, because we are decrypting the blocks in-place.
Block lastBlock = initializationVector;
for (std::size_t i = 0; i < blocks.size(); i++)
{
// Print reports if desired. If we have > 1000 blocks, print one report every 100 blocks. Otherwise for every 10th block.
if ((i % ((blocks.size() > 1000) ? 100 : 10) == 0) && (printProgress))
std::cout << "Decrypting... (Block " << i << " / " << blocks.size() << " - " << ((float)i*100/ blocks.size()) << "%)" << std::endl;
Block tmpCopy = blocks[i];
blocks[i] = feistel.Decipher(blocks[i]) ^ lastBlock; // Decipher cipher block [i] and then xor it with the last cipher block [i-1] we've had
lastBlock = std::move(tmpCopy);
}
// Concatenate ciphertext blocks back into a flexblock
std::stringstream ss;
for (Block& b : blocks)
ss << b;
// Return it
return ss.str();
}
// These pragmas only work for MSVC and g++, as far as i know. Beware!!!
#if defined _WIN32 || defined _WIN64
#pragma optimize("", off )
#elif defined __GNUG__
#pragma GCC push_options
#pragma GCC optimize ("O0")
#endif
void GhettoCipher::Cipher::ZeroKeyMemory()
{
key.reset();
return;
}
#if defined _WIN32 || defined _WIN64
#pragma optimize("", on )
#elif defined __GNUG__
#pragma GCC pop_options
#endif
/*** ./../GhettoCrypt/Feistel.cpp ***/
#include <unordered_map>
GhettoCipher::Feistel::Feistel(const Block& key)
{
SetKey(key);
return;
}
GhettoCipher::Feistel::~Feistel()
{
ZeroKeyMemory();
return;
}
void GhettoCipher::Feistel::SetKey(const Block& key)
{
GenerateRoundKeys(key);
return;
}
GhettoCipher::Block GhettoCipher::Feistel::Encipher(const Block& data)
{
return Run(data, false);
}
GhettoCipher::Block GhettoCipher::Feistel::Decipher(const Block& data)
{
return Run(data, true);
}
GhettoCipher::Block GhettoCipher::Feistel::Run(const Block& data, bool reverseKeys)
{
const auto splitData = FeistelSplit(data);
GhettoCipher::Halfblock l = splitData.first;
GhettoCipher::Halfblock r = splitData.second;
Halfblock tmp;
for (std::size_t i = 0; i < N_ROUNDS; i++)
{
// Calculate key index
std::size_t keyIndex;
if (reverseKeys)
keyIndex = N_ROUNDS - i - 1;
else
keyIndex = i;
// Do a feistel round
tmp = r;
r = l ^ F(r, roundKeys[keyIndex]);
l = tmp;
}
// Block has finished de*ciphering.
// Let's generate a new set of round keys.
GenerateRoundKeys((Block)roundKeys.back());
return FeistelCombine(r, l);
}
GhettoCipher::Halfblock GhettoCipher::Feistel::F(Halfblock m, const Block& key)
{
// Made-up F function
// Expand to full bitwidth
Block m_expanded = ExpansionFunction(m);
// Shift to left by 1
m_expanded = Shiftl(m_expanded, 1);
// Xor with key
m_expanded ^= key;
// Non-linearly apply subsitution boxes
std::stringstream ss;
const std::string m_str = m_expanded.to_string();
for (std::size_t i = 0; i < BLOCK_SIZE; i += 4)
{
ss << SBox(m_str.substr(i, 4));
}
m_expanded = Block(ss.str());
// Return the compressed version
return CompressionFunction(m_expanded);
}
std::pair<GhettoCipher::Halfblock, GhettoCipher::Halfblock> GhettoCipher::Feistel::FeistelSplit(const Block& block)
{
const std::string bits = block.to_string();
Halfblock l(bits.substr(0, bits.size() / 2));
Halfblock r(bits.substr(bits.size() / 2));
return std::make_pair(l, r);
}
GhettoCipher::Block GhettoCipher::Feistel::FeistelCombine(const Halfblock& l, const Halfblock& r)
{
return Block(l.to_string() + r.to_string());
}
GhettoCipher::Block GhettoCipher::Feistel::ExpansionFunction(const Halfblock& block)
{
std::stringstream ss;
const std::string bits = block.to_string();
std::unordered_map<std::string, std::string> expansionMap;
expansionMap["00"] = "1101";
expansionMap["01"] = "1000";
expansionMap["10"] = "0010";
expansionMap["11"] = "0111";
// We have to double the bits!
for (std::size_t i = 0; i < HALFBLOCK_SIZE; i += 2)
{
const std::string sub = bits.substr(i, 2);
ss << expansionMap[sub];
}
return Block(ss.str());
}
GhettoCipher::Halfblock GhettoCipher::Feistel::CompressionFunction(const Block& block)
{
std::stringstream ss;
const std::string bits = block.to_string();
std::unordered_map<std::string, std::string> compressionMap;
compressionMap["0000"] = "10";
compressionMap["0001"] = "01";
compressionMap["0010"] = "10";
compressionMap["0011"] = "10";
compressionMap["0100"] = "11";
compressionMap["0101"] = "01";
compressionMap["0110"] = "00";
compressionMap["0111"] = "11";
compressionMap["1000"] = "01";
compressionMap["1001"] = "00";
compressionMap["1010"] = "11";
compressionMap["1011"] = "00";
compressionMap["1100"] = "11";
compressionMap["1101"] = "10";
compressionMap["1110"] = "00";
compressionMap["1111"] = "01";
// We have to half the bits!
for (std::size_t i = 0; i < BLOCK_SIZE; i += 4)
{
const std::string sub = bits.substr(i, 4);
ss << compressionMap[sub];
}
return Halfblock(ss.str());
}
std::string GhettoCipher::Feistel::SBox(const std::string& in)
{
static std::unordered_map<std::string, std::string> subMap;
static bool mapInitialized = false;
if (!mapInitialized)
{
subMap["0000"] = "1100";
subMap["0001"] = "1000";
subMap["0010"] = "0001";
subMap["0011"] = "0111";
subMap["0100"] = "1011";
subMap["0101"] = "0011";
subMap["0110"] = "1101";
subMap["0111"] = "1111";
subMap["1000"] = "0000";
subMap["1001"] = "1010";
subMap["1010"] = "0100";
subMap["1011"] = "1001";
subMap["1100"] = "0010";
subMap["1101"] = "1110";
subMap["1110"] = "0101";
subMap["1111"] = "0110";
mapInitialized = true;
}
return subMap[in];
}
void GhettoCipher::Feistel::GenerateRoundKeys(const Block& seedKey)
{
// Clear initial key memory
ZeroKeyMemory();
roundKeys = Keyset();
// Derive the initial two round keys
// Compress- substitute, and expand the seed key to form the initial and the second-initial round key
// This action is non-linear and irreversible, and thus strenghtens security.
Halfblock compressedSeed1 = CompressionFunction(seedKey);
Halfblock compressedSeed2 = CompressionFunction(Shiftl(seedKey, 1)); // Shifting one key by 1 will result in a completely different compression
// To add further confusion, let's shift seed1 by 1 aswell (after compression, but before substitution)
// but only if the total number of bits set are a multiple of 3
// if it is a multiple of 4, we'll shift it by 1 into the opposite direction
const std::size_t setBits1 = compressedSeed1.count();
if (setBits1 % 4 == 0)
compressedSeed1 = Shiftr(compressedSeed1, 1);
else if (setBits1 % 3 == 0)
compressedSeed1 = Shiftl(compressedSeed1, 1);
// Now apply substitution
std::stringstream ssKey1;
std::stringstream ssKey2;
const std::string bitsKey1 = compressedSeed1.to_string();
const std::string bitsKey2 = compressedSeed2.to_string();
for (std::size_t i = 0; i < HALFBLOCK_SIZE; i += 4)
{
ssKey1 << SBox(bitsKey1.substr(i, 4));
ssKey2 << SBox(bitsKey2.substr(i, 4));
}
compressedSeed1 = Halfblock(ssKey1.str());
compressedSeed2 = Halfblock(ssKey2.str());
// Now extrapolate them to BLOCK_SIZE (key size) again
// Xor with the original seed key to get rid of the repititions caused by the expansion
roundKeys[0] = ExpansionFunction(compressedSeed1) ^ seedKey;
roundKeys[1] = ExpansionFunction(compressedSeed2) ^ seedKey;
// Now derive all other round keys
for (std::size_t i = 2; i < roundKeys.size(); i++)
{
// Initialize new round key with last round key
Block newKey = roundKeys[i - 1];
// Shift to left by how many bits are set, modulo 8
newKey = Shiftl(newKey, newKey.count() % 8); // This action is irreversible
// Split into two halfblocks,
// apply F() to one halfblock with rk[i-2],
// xor the other one with it
// and put them back together
auto halfkeys = FeistelSplit(newKey);
Halfblock halfkey1 = F(halfkeys.first, roundKeys[i - 2]);
Halfblock halfkey2 = halfkeys.second ^ halfkey1;
roundKeys[i] = FeistelCombine(halfkey1, halfkey2);
}
return;
}
// These pragmas only work for MSVC and g++, as far as i know. Beware!!!
#if defined _WIN32 || defined _WIN64
#pragma optimize("", off )
#elif defined __GNUG__
#pragma GCC push_options
#pragma GCC optimize ("O0")
#endif
void GhettoCipher::Feistel::ZeroKeyMemory()
{
for (Block& key : roundKeys)
key.reset();
return;
}
#if defined _WIN32 || defined _WIN64
#pragma optimize("", on )
#elif defined __GNUG__
#pragma GCC pop_options
#endif
/*** ./../GhettoCrypt/GhettoCryptWrapper.cpp ***/
std::string GhettoCipher::GhettoCryptWrapper::EncryptString(const std::string& cleartext, const std::string& password)
{
// Instanciate our cipher and supply a key
const Block key = PasswordToKey(password);
Cipher cipher(key);
// Recode the ascii-string to bits
const Flexblock cleartext_bits = StringToBits(cleartext);
// Encrypt our cleartext bits
const Flexblock ciphertext_bits = cipher.Encipher(cleartext_bits);
// Recode the ciphertext bits to a hex-string
const std::string ciphertext = BitsToHexstring(ciphertext_bits);
// Return it
return ciphertext;
}
std::string GhettoCipher::GhettoCryptWrapper::DecryptString(const std::string& ciphertext, const std::string& password)
{
// Instanciate our cipher and supply a key
const Block key = PasswordToKey(password);
Cipher cipher(key);
// Recode the hex-string to bits
const Flexblock ciphertext_bits = HexstringToBits(ciphertext);
// Decrypt the ciphertext bits
const std::string cleartext_bits = cipher.Decipher(ciphertext_bits);
// Recode the cleartext bits to an ascii-string
const std::string cleartext = BitsToString(cleartext_bits);
// Return it
return cleartext;
}
bool GhettoCipher::GhettoCryptWrapper::EncryptFile(const std::string& filename_in, const std::string& filename_out, const std::string& password, bool printProgressReport)
{
try
{
// Read the file to bits
const Flexblock cleartext_bits = ReadFileToBits(filename_in);
// Instanciate our cipher and supply a key
const Block key = PasswordToKey(password);
Cipher cipher(key);
// Encrypt our cleartext bits
const Flexblock ciphertext_bits = cipher.Encipher(cleartext_bits, printProgressReport);
// Write our ciphertext bits to file
WriteBitsToFile(filename_out, ciphertext_bits);
return true;
}
catch (std::runtime_error&)
{
return false;
}
}
bool GhettoCipher::GhettoCryptWrapper::DecryptFile(const std::string& filename_in, const std::string& filename_out, const std::string& password, bool printProgressReport)
{
try
{
// Read the file to bits
const Flexblock ciphertext_bits = ReadFileToBits(filename_in);
// Instanciate our cipher and supply a key
const Block key = PasswordToKey(password);
Cipher cipher(key);
// Decrypt the ciphertext bits
const Flexblock cleartext_bits = cipher.Decipher(ciphertext_bits, printProgressReport);
// Write our cleartext bits to file
WriteBitsToFile(filename_out, cleartext_bits);
return true;
}
catch (std::runtime_error&)
{
return false;
}
}
/*** ./../GhettoCrypt/InitializationVector.cpp ***/
GhettoCipher::InitializationVector::InitializationVector(const Block& seed)
{
// We'll generate our initialization vector by encrypting our seed with itself as a key
// iv = E(M=seed, K=seed)
iv = Feistel(seed).Encipher(seed);
}
GhettoCipher::InitializationVector::operator GhettoCipher::Block() const
{
return iv;
}