/* * (C) 2009 Jack Lloyd * * Distributed under the terms of the Botan license */ #include #include #include #include #include #include #include #include using namespace Botan; /** Encrypt and decrypt small rows */ class Row_Encryptor { public: Row_Encryptor(const std::string& passphrase, RandomNumberGenerator& rng); Row_Encryptor(const std::string& passphrase, const MemoryRegion& salt); std::string encrypt(const std::string& input, const MemoryRegion& salt); std::string decrypt(const std::string& input, const MemoryRegion& salt); SecureVector get_s2k_salt() const { return s2k_salt; } private: void init(const std::string& passphrase); Row_Encryptor(const Row_Encryptor&) {} Row_Encryptor& operator=(const Row_Encryptor&) { return (*this); } SecureVector s2k_salt; Pipe enc_pipe, dec_pipe; EAX_Encryption* eax_enc; // owned by enc_pipe EAX_Decryption* eax_dec; // owned by dec_pipe; }; Row_Encryptor::Row_Encryptor(const std::string& passphrase, RandomNumberGenerator& rng) { s2k_salt.resize(10); // 80 bits rng.randomize(&s2k_salt[0], s2k_salt.size()); init(passphrase); } Row_Encryptor::Row_Encryptor(const std::string& passphrase, const MemoryRegion& salt) { s2k_salt = salt; init(passphrase); } void Row_Encryptor::init(const std::string& passphrase) { std::auto_ptr s2k(get_s2k("PBKDF2(SHA-160)")); SecureVector key = s2k->derive_key(32, passphrase, &s2k_salt[0], s2k_salt.size(), 10000).bits_of(); /* Save pointers to the EAX objects so we can change the IV as needed */ Algorithm_Factory& af = global_state().algorithm_factory(); const BlockCipher* proto = af.prototype_block_cipher("Serpent"); if(!proto) throw std::runtime_error("Could not get a Serpent proto object"); enc_pipe.append(eax_enc = new EAX_Encryption(proto->clone())); dec_pipe.append(eax_dec = new EAX_Decryption(proto->clone())); eax_enc->set_key(key); eax_dec->set_key(key); } std::string Row_Encryptor::encrypt(const std::string& input, const MemoryRegion& salt) { eax_enc->set_iv(salt); enc_pipe.process_msg(input); return enc_pipe.read_all_as_string(Pipe::LAST_MESSAGE); } std::string Row_Encryptor::decrypt(const std::string& input, const MemoryRegion& salt) { eax_dec->set_iv(salt); dec_pipe.process_msg(input); return dec_pipe.read_all_as_string(Pipe::LAST_MESSAGE); } /* * Test code follows: */ int main() { Botan::LibraryInitializer init; AutoSeeded_RNG rng; const std::string secret_passphrase = "secret passphrase"; Row_Encryptor encryptor("secret passphrase", rng); std::vector original_inputs; for(u32bit i = 0; i != 50000; ++i) { std::ostringstream out; u32bit output_bytes = rng.next_byte(); for(u32bit j = 0; j != output_bytes; ++j) out << std::hex << (int)rng.next_byte(); original_inputs.push_back(out.str()); } std::vector encrypted_values; MemoryVector salt(4); // keep out of loop to avoid excessive dynamic allocation for(u32bit i = 0; i != original_inputs.size(); ++i) { std::string input = original_inputs[i]; for(u32bit j = 0; j != 4; ++j) salt[j] = (i >> 8) & 0xFF; encrypted_values.push_back(encryptor.encrypt(input, salt)); } for(u32bit i = 0; i != encrypted_values.size(); ++i) { std::string ciphertext = encrypted_values[i]; // NOTE: same salt value as previous loop (index value) for(u32bit j = 0; j != 4; ++j) salt[j] = (i >> 8) & 0xFF; std::string output = encryptor.decrypt(ciphertext, salt); if(output != original_inputs[i]) std::cout << "BOOM " << i << "\n"; } Row_Encryptor test_s2k_salt_copy(secret_passphrase, encryptor.get_s2k_salt()); salt.clear(); // all-0 std::string test = test_s2k_salt_copy.decrypt(encrypted_values[0], salt); if(test != original_inputs[0]) std::cout << "S2K salt copy failed to decrypt properly\n"; return 0; }