Added class for hashing, that is now used for password to key transformation

GCryptLib/include/GCrypt/Hasher.h

@@ -0,0 +1,34 @@
+#ifndef GCRYPT_HASHER_H
+#define GCRYPT_HASHER_H
+
+#include "GCrypt/Flexblock.h"
+#include "GCrypt/Block.h"
+#include "GCrypt/Cipher.h"
+
+namespace Leonetienne::GCrypt {
+  /** This class implements a hash function, based on the GCrypt cipher
+  */
+  class Hasher {
+  public:
+    Hasher();
+
+    //! Will add the hash value of `data` to the hashsum
+    void Digest(const Block& data);
+
+    //! Will return the current hashsum
+    const Block& GetHashsum() const;
+
+    //! Will calculate a hashsum for `data`.
+    static Block CalculateHashsum(const Flexblock& data);
+
+  private:
+    //! The cipher to use
+    Cipher cipher;
+
+    //! The current state of the hashsum
+    Block block;
+  };
+}
+
+#endif
+

GCryptLib/include/GCrypt/Util.h

@@ -1,4 +1,6 @@
-#pragma once
+#ifndef GCRYPT_UTIL_H
+#define GCRYPT_UTIL_H
+
 #include <bitset>
 #include <sstream>
 #include <fstream>
@@ -78,7 +80,7 @@ namespace Leonetienne::GCrypt {
         }
 
         // Pad rest with zeores
-        return Block(PadStringToLength(ss.str(), 128, '0', false));
+        return Block(PadStringToLength(ss.str(), BLOCK_SIZE, '0', false));
     }
 
     //! Will convert a string to a flexible data block
@@ -226,43 +228,7 @@ namespace Leonetienne::GCrypt {
     }
 
     //! Creates a key of size BLOCK_SIZE from a password of arbitrary length.
-    //! 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) {
-        // Let's provide a nice initial value to be sure even a password of length 0 results in a proper key
-        Block b = InitializationVector(StringToBitblock("3J7IipfQTDJbO8jtasz9PgWui6faPaEMOuVuAqyhB1S2CRcLw5caawewgDUEG1WN"));
-
-        // 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) {
-            const Block fragment = StringToBitblock(
-                PadStringToLength(in.substr(i, BLOCK_SIZE / 8), BLOCK_SIZE / 8, 0, false)
-            );
-
-            // To provide confusion, xor the blocks together
-            // To provide diffusion, hash fragment to fragment' first
-            b ^= Block(Cipher(fragment, Cipher::CIPHER_DIRECTION::ENCIPHER).Digest(fragment).to_string());
-        }
-
-        return b;
-    }
-
-    //! Will reduce a flexblock (they are of arbitrary length) to a single block.
-    //! This single block should change completely, if a single bit in the input flexblock changes anywhere.
-    inline Block ReductionFunction_Flexblock2Block(const Flexblock& in) {
-        Block b; // No initialization vector needed here
-
-        // Segment the input in segments of BLOCK_SIZE, and xor them together.
-        for (std::size_t i = 0; i < in.size(); i += BLOCK_SIZE) {
-            const Block fragment = Block(PadStringToLength(in.substr(i, BLOCK_SIZE), BLOCK_SIZE, 0, false));
-
-            // To provide confusion, xor the blocks together
-            // To provide diffusion, hash fragment to fragment' first
-            b ^= Block(Cipher(fragment, Cipher::CIPHER_DIRECTION::ENCIPHER).Digest(fragment).to_string());
-        }
-
-        return b;
-    }
+    Block PasswordToKey(const std::string& in);
 
     //! Will read a file into a flexblock
     inline Flexblock ReadFileToBits(const std::string& filepath) {
@@ -307,3 +273,5 @@ namespace Leonetienne::GCrypt {
     }
 }
 
+#endif
+

GCryptLib/src/Hasher.cpp

@@ -0,0 +1,57 @@
+#include "GCrypt/Hasher.h"
+#include "GCrypt/Util.h"
+#include "GCrypt/InitializationVector.h"
+
+namespace Leonetienne::GCrypt {
+
+  Hasher::Hasher() :
+    // Initialize our cipher with a static, but randomly distributed key.
+    cipher(
+        StringToBitblock("CfRtNdMTP4Y5CWRd"),
+        Cipher::CIPHER_DIRECTION::ENCIPHER
+    ) {
+      block = InitializationVector(StringToBitblock("3J7IipfQTDJbO8jtasz9PgWui6faPaEMOuVuAqyhB1S2CRcLw5caawewgDUEG1WN"));
+
+      return;
+  }
+ 
+  void Hasher::Digest(const Block& data) {
+    // Encipher the current block, and xor it on the current hashsum
+    block ^= cipher.Digest(data);
+    return;
+  }
+
+  const Block& Hasher::GetHashsum() const {
+    return block;
+  }
+
+  Block Hasher::CalculateHashsum(const Flexblock& data) {
+    // Split input 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))
+      );
+    }
+
+    // Add an additional block, containing the length of the input
+    std::stringstream ss;
+    ss << data.length();
+    const Block lengthBlock = StringToBitblock(ss.str());
+    blocks.push_back(lengthBlock);
+
+    // Create hasher instance
+    Hasher hasher;
+
+    // Digest all blocks
+    for (Block& block : blocks) {
+      hasher.Digest(block);
+    }
+
+    // Return the total hashsum
+    return hasher.GetHashsum();
+  }
+
+}
+

GCryptLib/src/Util.cpp

@@ -0,0 +1,13 @@
+#include "GCrypt/Util.h"
+#include "GCrypt/Hasher.h"
+
+namespace Leonetienne::GCrypt {
+  Block PasswordToKey(const std::string& in) {
+    // We already have a hashing algorithm, so why not use it
+    // Yeah, this won't work, because it would create an include loop. This method needs to be outsourced to a cpp file..
+
+    const Block hashedPassword = Hasher::CalculateHashsum(StringToBits(in));
+    return hashedPassword;
+  }
+}
+