compiled single-header

INCLUDE/GhettoCrypt.cpp

@@ -35,16 +35,18 @@
 
 GhettoCipher::Cipher::Cipher(const Block& key)
 	:
-	key { key }
+	key { key },
+	initializationVector(InitializationVector(key))
 {
 
 	return;
 }
 
 GhettoCipher::Cipher::Cipher(const std::string& password)
+	:
+	key { PasswordToKey(password) },
+	initializationVector(InitializationVector(key))
 {
-	key = PasswordToKey(password);
-
 	return;
 }
 
@@ -91,8 +93,8 @@ GhettoCipher::Flexblock GhettoCipher::Cipher::Encipher(const Flexblock& data, bo
 		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] : emptyBlock;
+		const Block& lastBlock = (i>0) ? blocks[i-1] : initializationVector;
-		blocks[i] = feistel.Encipher(blocks[i] ^ lastBlock);
+		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
@@ -118,7 +120,7 @@ GhettoCipher::Flexblock GhettoCipher::Cipher::Decipher(const Flexblock& data, bo
 	Feistel feistel(key);
 
 	// We can't do this in-loop for decryption, because we are decrypting the blocks in-place.
-	Block lastBlock = emptyBlock;
+	Block lastBlock = initializationVector;
 	
 	for (std::size_t i = 0; i < blocks.size(); i++)
 	{
@@ -128,7 +130,7 @@ GhettoCipher::Flexblock GhettoCipher::Cipher::Decipher(const Flexblock& data, bo
 
 		Block tmpCopy = blocks[i];
 
-		blocks[i] = feistel.Decipher(blocks[i]) ^ lastBlock;
+		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);
 	}
@@ -160,8 +162,6 @@ void GhettoCipher::Cipher::ZeroKeyMemory()
 #pragma GCC pop_options
 #endif
 
-const GhettoCipher::Block GhettoCipher::Cipher::emptyBlock;
-
 
 /*** ./../GhettoCrypt/Feistel.cpp ***/
 
@@ -186,17 +186,17 @@ void GhettoCipher::Feistel::SetKey(const Block& key)
     return;
 }
 
-GhettoCipher::Block GhettoCipher::Feistel::Encipher(const Block& data) const
+GhettoCipher::Block GhettoCipher::Feistel::Encipher(const Block& data)
 {
     return Run(data, false);
 }
 
-GhettoCipher::Block GhettoCipher::Feistel::Decipher(const Block& data) const
+GhettoCipher::Block GhettoCipher::Feistel::Decipher(const Block& data)
 {
     return Run(data, true);
 }
 
-GhettoCipher::Block GhettoCipher::Feistel::Run(const Block& data, bool reverseKeys) const
+GhettoCipher::Block GhettoCipher::Feistel::Run(const Block& data, bool reverseKeys)
 {
     const auto splitData = FeistelSplit(data);
     GhettoCipher::Halfblock l = splitData.first;
@@ -219,6 +219,10 @@ GhettoCipher::Block GhettoCipher::Feistel::Run(const Block& data, bool reverseKe
         l = tmp;
     }
 
+    // Block has finished de*ciphering.
+    // Let's generate a new set of round keys.
+    GenerateRoundKeys((Block)roundKeys.back());
+
     return FeistelCombine(r, l);
 }
 
@@ -239,7 +243,7 @@ GhettoCipher::Halfblock GhettoCipher::Feistel::F(Halfblock m, const Block& key)
     std::stringstream ss;
     const std::string m_str = m_expanded.to_string();
 
-    for (std::size_t i = 0; i < m_str.size(); i += 4)
+    for (std::size_t i = 0; i < BLOCK_SIZE; i += 4)
     {
         ss << SBox(m_str.substr(i, 4));
     }
@@ -277,7 +281,7 @@ GhettoCipher::Block GhettoCipher::Feistel::ExpansionFunction(const Halfblock& bl
     expansionMap["11"] = "0111";
 
     // We have to double the bits!
-    for (std::size_t i = 0; i < bits.size(); i += 2)
+    for (std::size_t i = 0; i < HALFBLOCK_SIZE; i += 2)
     {
         const std::string sub = bits.substr(i, 2);
         ss << expansionMap[sub];
@@ -310,7 +314,7 @@ GhettoCipher::Halfblock GhettoCipher::Feistel::CompressionFunction(const Block&
     compressionMap["1111"] = "01";
 
     // We have to half the bits!
-    for (std::size_t i = 0; i < bits.size(); i += 4)
+    for (std::size_t i = 0; i < BLOCK_SIZE; i += 4)
     {
         const std::string sub = bits.substr(i, 4);
         ss << compressionMap[sub];
@@ -349,19 +353,67 @@ std::string GhettoCipher::Feistel::SBox(const std::string& in)
 
 void GhettoCipher::Feistel::GenerateRoundKeys(const Block& seedKey)
 {
-    // Generate round keys via output feedback modus (OFM) method
-
     // Clear initial key memory
     ZeroKeyMemory();
     roundKeys = Keyset();
 
-    // Generate new keys from the seed key
+    // Derive the initial two round keys
-    roundKeys[0] = seedKey;
+
-    roundKeys[1] = (Shiftl(seedKey, 32) ^ roundKeys[0]);
+    // 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++)
     {
-        roundKeys[i] = Shiftl(roundKeys[i - 1], i + 32) ^ roundKeys[i - 2];
+        // 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;
@@ -394,7 +446,8 @@ void GhettoCipher::Feistel::ZeroKeyMemory()
 std::string GhettoCipher::GhettoCryptWrapper::EncryptString(const std::string& cleartext, const std::string& password)
 {
 	// Instanciate our cipher and supply a key
-	Cipher cipher(password);
+	const Block key = PasswordToKey(password);
+	Cipher cipher(key);
 
 	// Recode the ascii-string to bits
 	const Flexblock cleartext_bits = StringToBits(cleartext);
@@ -412,7 +465,8 @@ std::string GhettoCipher::GhettoCryptWrapper::EncryptString(const std::string& c
 std::string GhettoCipher::GhettoCryptWrapper::DecryptString(const std::string& ciphertext, const std::string& password)
 {
 	// Instanciate our cipher and supply a key
-	Cipher cipher(password);
+	const Block key = PasswordToKey(password);
+	Cipher cipher(key);
 
 	// Recode the hex-string to bits
 	const Flexblock ciphertext_bits = HexstringToBits(ciphertext);
@@ -435,7 +489,8 @@ bool GhettoCipher::GhettoCryptWrapper::EncryptFile(const std::string& filename_i
 		const Flexblock cleartext_bits = ReadFileToBits(filename_in);
 
 		// Instanciate our cipher and supply a key
-		Cipher cipher(password);
+		const Block key = PasswordToKey(password);
+		Cipher cipher(key);
 
 		// Encrypt our cleartext bits
 		const Flexblock ciphertext_bits = cipher.Encipher(cleartext_bits, printProgressReport);
@@ -459,7 +514,8 @@ bool GhettoCipher::GhettoCryptWrapper::DecryptFile(const std::string& filename_i
 		const Flexblock ciphertext_bits = ReadFileToBits(filename_in);
 
 		// Instanciate our cipher and supply a key
-		Cipher cipher(password);
+		const Block key = PasswordToKey(password);
+		Cipher cipher(key);
 
 		// Decrypt the ciphertext bits
 		const Flexblock cleartext_bits = cipher.Decipher(ciphertext_bits, printProgressReport);
@@ -475,3 +531,20 @@ bool GhettoCipher::GhettoCryptWrapper::DecryptFile(const std::string& filename_i
 	}
 }
 
+
+/*** ./../GhettoCrypt/InitializationVector.cpp ***/
+
+#include <iostream>
+
+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;
+}
+

INCLUDE/GhettoCrypt.h

@@ -28,10 +28,41 @@
 
 #pragma once
 
-/*** ./../GhettoCrypt/Version.h ***/
+/*** ./../GhettoCrypt/GhettoCryptWrapper.h ***/
 
 #pragma once
-#define GHETTOCRYPT_VERSION 0.13
+#include <string>
+
+namespace GhettoCipher
+{
+	/** This class is a wrapper to make working with the GhettoCipher super easy with a python-like syntax
+	*/
+	class GhettoCryptWrapper
+	{
+	public:
+		//! Will encrypt a string and return it hexadecimally encoded.
+		static std::string EncryptString(const std::string& cleartext, const std::string& password);
+
+		//! Will decrypt a hexadecimally encoded string.
+		static std::string DecryptString(const std::string& ciphertext, const std::string& password);
+
+		//! Will encrypt a file.
+		//! Returns false if anything goes wrong (like, file-access).
+		//! @filename_in The file to be read.
+		//! @filename_out The file the encrypted version should be saved in.
+		static bool EncryptFile(const std::string& filename_in, const std::string& filename_out, const std::string& password, bool printProgressReport = false);
+
+		//! Will decrypt a file.
+		//! Returns false if anything goes wrong (like, file-access).
+		//! @filename_in The file to be read.
+		//! @filename_out The file the decrypted version should be saved in.
+		static bool DecryptFile(const std::string& filename_in, const std::string& filename_out, const std::string& password, bool printProgressReport = false);
+
+	private:
+		// No instanciation! >:(
+		GhettoCryptWrapper();
+	};
+}
 
 /*** ./../GhettoCrypt/Flexblock.h ***/
 
@@ -47,14 +78,22 @@ namespace GhettoCipher
 /*** ./../GhettoCrypt/Config.h ***/
 
 #pragma once
-#include <cstdint>
+#include <cstddef>
 
 namespace GhettoCipher
 {
+	// MUST BE A POWER OF 2 > 4
 	constexpr std::size_t BLOCK_SIZE = 512;
+
+	// MUST BE > 2
 	constexpr std::size_t N_ROUNDS = 64;
 }
 
+/*** ./../GhettoCrypt/Version.h ***/
+
+#pragma once
+#define GHETTOCRYPT_VERSION 0.21
+
 /*** ./../GhettoCrypt/SecureBitset.h ***/
 
 #pragma once
@@ -382,6 +421,17 @@ inline std::istream& operator>>(std::istream& ifs, const SecureBitset<T>& bs)
 }
 }
 
+/*** ./../GhettoCrypt/Halfblock.h ***/
+
+#pragma once
+#include <cstdint>
+
+namespace GhettoCipher
+{
+	constexpr std::size_t HALFBLOCK_SIZE = (BLOCK_SIZE / 2);
+	typedef SecureBitset<HALFBLOCK_SIZE> Halfblock;
+}
+
 /*** ./../GhettoCrypt/Block.h ***/
 
 #pragma once
@@ -391,12 +441,33 @@ namespace GhettoCipher
 	typedef SecureBitset<BLOCK_SIZE> Block;
 }
 
+/*** ./../GhettoCrypt/InitializationVector.h ***/
+
+#pragma once
+
+namespace GhettoCipher
+{
+	/** Will create a sudo-random Block based on a seed
+	*/
+	class InitializationVector
+	{
+	public:
+		InitializationVector(const GhettoCipher::Block& seed);
+
+		operator GhettoCipher::Block() const;
+
+	private:
+		GhettoCipher::Block iv;
+	};
+}
+
 /*** ./../GhettoCrypt/Util.h ***/
 
 #pragma once
 #include <bitset>
 #include <sstream>
 #include <fstream>
+#include <cstring>
 
 namespace GhettoCipher
 {
@@ -482,8 +553,8 @@ namespace GhettoCipher
         return Flexblock(ss.str());
     }
 
-    //! Will convert a fixed-size data block to a string
+    //! Will convert a fixed-size data block to a bytestring
-    inline std::string BitblockToString(const Block& bits)
+    inline std::string BitblockToBytes(const Block& bits)
     {
         std::stringstream ss;
 
@@ -497,8 +568,21 @@ namespace GhettoCipher
         return ss.str();
     }
     
-    //! Will convert a flexible data block to a string
+    //! Will convert a fixed-size data block to a string
-    inline std::string BitsToString(const Flexblock& bits)
+    //! The difference to BitblockToBytes() is, that it strips excess nullbytes
+    inline std::string BitblockToString(const Block& bits)
+    {
+        // Decode to bytes
+        std::string text = BitblockToBytes(bits);
+
+        // Dümp excess nullbytes
+        text.resize(strlen(text.data()));
+
+        return text;
+    }
+
+    //! Will convert a flexible data block to a bytestring
+    inline std::string BitsToBytes(const Flexblock& bits)
     {
         std::stringstream ss;
 
@@ -512,6 +596,19 @@ namespace GhettoCipher
         return ss.str();
     }
 
+    //! Will convert a flexible data block to a string
+    //! //! The difference to BitsToBytes() is, that it strips excess nullbytes
+    inline std::string BitsToString(const Flexblock& bits)
+    {
+        // Decode to bytes
+        std::string text = BitsToBytes(bits);
+
+        // Dümp excess nullbytes
+        text.resize(strlen(text.data()));
+
+        return text;
+    }
+
     //! Turns a fixed-size data block into a hex-string
     inline std::string BitblockToHexstring(const Block& b)
     {
@@ -594,8 +691,10 @@ namespace GhettoCipher
     }
 
     //! Creates a key of size BLOCK_SIZE from a password of arbitrary length.
-    //! Using passwords larger (in bits) than BLOCK_SIZE is not generally recommended.
+    //! Using passwords larger (in bits) than BLOCK_SIZE is generally not recommended.
-    //! Note that if your password is shorter (in bits) than BLOCK_SIZE, the rest of the key will be padded with 0x0. Further round-keys will be extrapolated though.
+    //! Note that if your password is shorter (in bits) than BLOCK_SIZE, the rest of the key will be padded with 0 (see next line!).
+    //! To provide a better initial key, (and to get rid of padding zeroes), the raw result (b) will be xor'd with an initialization vector based on b.
+    //! : return b ^ iv(b)
     inline Block PasswordToKey(const std::string& in)
     {
         Block b;
@@ -606,7 +705,7 @@ namespace GhettoCipher
                 PadStringToLength(in.substr(i, BLOCK_SIZE / 8), BLOCK_SIZE / 8, 0, false)
             );
 
-        return b;
+        return b ^ InitializationVector(b);
     }
 
     //! Will read a file into a flexblock
@@ -637,7 +736,7 @@ namespace GhettoCipher
     inline void WriteBitsToFile(const std::string& filepath, const Flexblock& bits)
     {
         // Convert bits to bytes
-        const std::string bytes = BitsToString(bits);
+        const std::string bytes = BitsToBytes(bits);
 
         // Write bits to file
         std::ofstream ofs(filepath, std::ios::binary);
@@ -652,42 +751,6 @@ namespace GhettoCipher
     }
 }
 
-/*** ./../GhettoCrypt/GhettoCryptWrapper.h ***/
-
-#pragma once
-#include <string>
-
-namespace GhettoCipher
-{
-	/** This class is a wrapper to make working with the GhettoCipher super easy with a python-like syntax
-	*/
-	class GhettoCryptWrapper
-	{
-	public:
-		//! Will encrypt a string and return it hexadecimally encoded.
-		static std::string EncryptString(const std::string& cleartext, const std::string& password);
-
-		//! Will decrypt a hexadecimally encoded string.
-		static std::string DecryptString(const std::string& ciphertext, const std::string& password);
-
-		//! Will encrypt a file.
-		//! Returns false if anything goes wrong (like, file-access).
-		//! @filename_in The file to be read.
-		//! @filename_out The file the encrypted version should be saved in.
-		static bool EncryptFile(const std::string& filename_in, const std::string& filename_out, const std::string& password, bool printProgressReport = false);
-
-		//! Will decrypt a file.
-		//! Returns false if anything goes wrong (like, file-access).
-		//! @filename_in The file to be read.
-		//! @filename_out The file the decrypted version should be saved in.
-		static bool DecryptFile(const std::string& filename_in, const std::string& filename_out, const std::string& password, bool printProgressReport = false);
-
-	private:
-		// No instanciation! >:(
-		GhettoCryptWrapper();
-	};
-}
-
 /*** ./../GhettoCrypt/Keyset.h ***/
 
 #pragma once
@@ -698,17 +761,6 @@ namespace GhettoCipher
 	typedef std::array<Block, N_ROUNDS> Keyset;
 }
 
-/*** ./../GhettoCrypt/Halfblock.h ***/
-
-#pragma once
-#include <cstdint>
-
-namespace GhettoCipher
-{
-	constexpr std::size_t HALFBLOCK_SIZE = (BLOCK_SIZE / 2);
-	typedef SecureBitset<HALFBLOCK_SIZE> Halfblock;
-}
-
 /*** ./../GhettoCrypt/Feistel.h ***/
 
 #pragma once
@@ -732,14 +784,14 @@ namespace GhettoCipher
 		void SetKey(const Block& key);
 
 		//! Will encipher a data block via the set seed-key
-		Block Encipher(const Block& data) const;
+		Block Encipher(const Block& data);
 
 		//! Will decipher a data block via the set seed-key
-		Block Decipher(const Block& data) const;
+		Block Decipher(const Block& data);
 
 	private:
 		//! Will run the feistel rounds, with either regular key order or reversed key order
-		Block Run(const Block& data, bool reverseKeys) const;
+		Block Run(const Block& data, bool reverseKeys);
 
 		//! Arbitrary cipher function
 		static Halfblock F(Halfblock m, const Block& key);
@@ -807,6 +859,6 @@ namespace GhettoCipher
 		void ZeroKeyMemory();
 
 		// Initial value for cipher block chaining
-		static const Block emptyBlock;
+		Block initializationVector;
 	};
 }