Move lib into src

1 files changed, 285 insertions, 0 deletions

diff --git a/src/lib/modes/xts/xts.cpp b/src/lib/modes/xts/xts.cpp
new file mode 100644
index 000000000..02da5fa5d
--- /dev/null
+++ b/src/lib/modes/xts/xts.cpp
@@ -0,0 +1,285 @@
+/*
+* XTS Mode
+* (C) 2009,2013 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#include <botan/xts.h>
+#include <botan/loadstor.h>
+#include <botan/internal/xor_buf.h>
+#include <botan/internal/rounding.h>
+
+namespace Botan {
+
+namespace {
+
+void poly_double_128(byte out[], const byte in[])
+   {
+   u64bit X0 = load_le<u64bit>(in, 0);
+   u64bit X1 = load_le<u64bit>(in, 1);
+
+   const bool carry = (X1 >> 63);
+
+   X1 = (X1 << 1) | (X0 >> 63);
+   X0 = (X0 << 1);
+
+   if(carry)
+      X0 ^= 0x87;
+
+   store_le(out, X0, X1);
+   }
+
+void poly_double_64(byte out[], const byte in[])
+   {
+   u64bit X = load_le<u64bit>(in, 0);
+   const bool carry = (X >> 63);
+   X <<= 1;
+   if(carry)
+      X ^= 0x1B;
+   store_le(X, out);
+   }
+
+inline void poly_double(byte out[], const byte in[], size_t size)
+   {
+   if(size == 8)
+      poly_double_64(out, in);
+   else
+      poly_double_128(out, in);
+   }
+
+}
+
+XTS_Mode::XTS_Mode(BlockCipher* cipher) : m_cipher(cipher)
+   {
+   if(m_cipher->block_size() != 8 && m_cipher->block_size() != 16)
+      throw std::invalid_argument("Bad cipher for XTS: " + cipher->name());
+
+   m_tweak_cipher.reset(m_cipher->clone());
+   m_tweak.resize(update_granularity());
+   }
+
+void XTS_Mode::clear()
+   {
+   m_cipher->clear();
+   m_tweak_cipher->clear();
+   zeroise(m_tweak);
+   }
+
+std::string XTS_Mode::name() const
+   {
+   return cipher().name() + "/XTS";
+   }
+
+size_t XTS_Mode::update_granularity() const
+   {
+   return cipher().parallel_bytes();
+   }
+
+size_t XTS_Mode::minimum_final_size() const
+   {
+   return cipher().block_size() + 1;
+   }
+
+Key_Length_Specification XTS_Mode::key_spec() const
+   {
+   return cipher().key_spec().multiple(2);
+   }
+
+size_t XTS_Mode::default_nonce_length() const
+   {
+   return cipher().block_size();
+   }
+
+bool XTS_Mode::valid_nonce_length(size_t n) const
+   {
+   return cipher().block_size() == n;
+   }
+
+void XTS_Mode::key_schedule(const byte key[], size_t length)
+   {
+   const size_t key_half = length / 2;
+
+   if(length % 2 == 1 || !m_cipher->valid_keylength(key_half))
+      throw Invalid_Key_Length(name(), length);
+
+   m_cipher->set_key(&key[0], key_half);
+   m_tweak_cipher->set_key(&key[key_half], key_half);
+   }
+
+secure_vector<byte> XTS_Mode::start(const byte nonce[], size_t nonce_len)
+   {
+   if(!valid_nonce_length(nonce_len))
+      throw Invalid_IV_Length(name(), nonce_len);
+
+   copy_mem(&m_tweak[0], nonce, nonce_len);
+   m_tweak_cipher->encrypt(&m_tweak[0]);
+
+   update_tweak(0);
+
+   return secure_vector<byte>();
+   }
+
+void XTS_Mode::update_tweak(size_t which)
+   {
+   const size_t BS = m_tweak_cipher->block_size();
+
+   if(which > 0)
+      poly_double(&m_tweak[0], &m_tweak[(which-1)*BS], BS);
+
+   const size_t blocks_in_tweak = update_granularity() / BS;
+
+   for(size_t i = 1; i < blocks_in_tweak; ++i)
+      poly_double(&m_tweak[i*BS], &m_tweak[(i-1)*BS], BS);
+   }
+
+size_t XTS_Encryption::output_length(size_t input_length) const
+   {
+   return round_up(input_length, cipher().block_size());
+   }
+
+void XTS_Encryption::update(secure_vector<byte>& buffer, size_t offset)
+   {
+   BOTAN_ASSERT(buffer.size() >= offset, "Offset is sane");
+   const size_t sz = buffer.size() - offset;
+   byte* buf = &buffer[offset];
+
+   const size_t BS = cipher().block_size();
+
+   BOTAN_ASSERT(sz % BS == 0, "Input is full blocks");
+   size_t blocks = sz / BS;
+
+   const size_t blocks_in_tweak = update_granularity() / BS;
+
+   while(blocks)
+      {
+      const size_t to_proc = std::min(blocks, blocks_in_tweak);
+      const size_t to_proc_bytes = to_proc * BS;
+
+      xor_buf(buf, tweak(), to_proc_bytes);
+      cipher().encrypt_n(buf, buf, to_proc);
+      xor_buf(buf, tweak(), to_proc_bytes);
+
+      buf += to_proc * BS;
+      blocks -= to_proc;
+
+      update_tweak(to_proc);
+      }
+   }
+
+void XTS_Encryption::finish(secure_vector<byte>& buffer, size_t offset)
+   {
+   BOTAN_ASSERT(buffer.size() >= offset, "Offset is sane");
+   const size_t sz = buffer.size() - offset;
+   byte* buf = &buffer[offset];
+
+   BOTAN_ASSERT(sz >= minimum_final_size(), "Have sufficient final input");
+
+   const size_t BS = cipher().block_size();
+
+   if(sz % BS == 0)
+      {
+      update(buffer, offset);
+      }
+   else
+      {
+      // steal ciphertext
+      const size_t full_blocks = ((sz / BS) - 1) * BS;
+      const size_t final_bytes = sz - full_blocks;
+      BOTAN_ASSERT(final_bytes > BS && final_bytes < 2*BS, "Left over size in expected range");
+
+      secure_vector<byte> last(buf + full_blocks, buf + full_blocks + final_bytes);
+      buffer.resize(full_blocks + offset);
+      update(buffer, offset);
+
+      xor_buf(last, tweak(), BS);
+      cipher().encrypt(last);
+      xor_buf(last, tweak(), BS);
+
+      for(size_t i = 0; i != final_bytes - BS; ++i)
+         std::swap(last[i], last[i + BS]);
+
+      xor_buf(last, tweak() + BS, BS);
+      cipher().encrypt(last);
+      xor_buf(last, tweak() + BS, BS);
+
+      buffer += last;
+      }
+   }
+
+size_t XTS_Decryption::output_length(size_t input_length) const
+   {
+   // might be less
+   return input_length;
+   }
+
+void XTS_Decryption::update(secure_vector<byte>& buffer, size_t offset)
+   {
+   BOTAN_ASSERT(buffer.size() >= offset, "Offset is sane");
+   const size_t sz = buffer.size() - offset;
+   byte* buf = &buffer[offset];
+
+   const size_t BS = cipher().block_size();
+
+   BOTAN_ASSERT(sz % BS == 0, "Input is full blocks");
+   size_t blocks = sz / BS;
+
+   const size_t blocks_in_tweak = update_granularity() / BS;
+
+   while(blocks)
+      {
+      const size_t to_proc = std::min(blocks, blocks_in_tweak);
+      const size_t to_proc_bytes = to_proc * BS;
+
+      xor_buf(buf, tweak(), to_proc_bytes);
+      cipher().decrypt_n(buf, buf, to_proc);
+      xor_buf(buf, tweak(), to_proc_bytes);
+
+      buf += to_proc * BS;
+      blocks -= to_proc;
+
+      update_tweak(to_proc);
+      }
+   }
+
+void XTS_Decryption::finish(secure_vector<byte>& buffer, size_t offset)
+   {
+   BOTAN_ASSERT(buffer.size() >= offset, "Offset is sane");
+   const size_t sz = buffer.size() - offset;
+   byte* buf = &buffer[offset];
+
+   BOTAN_ASSERT(sz >= minimum_final_size(), "Have sufficient final input");
+
+   const size_t BS = cipher().block_size();
+
+   if(sz % BS == 0)
+      {
+      update(buffer, offset);
+      }
+   else
+      {
+      // steal ciphertext
+      const size_t full_blocks = ((sz / BS) - 1) * BS;
+      const size_t final_bytes = sz - full_blocks;
+      BOTAN_ASSERT(final_bytes > BS && final_bytes < 2*BS, "Left over size in expected range");
+
+      secure_vector<byte> last(buf + full_blocks, buf + full_blocks + final_bytes);
+      buffer.resize(full_blocks + offset);
+      update(buffer, offset);
+
+      xor_buf(last, tweak() + BS, BS);
+      cipher().decrypt(last);
+      xor_buf(last, tweak() + BS, BS);
+
+      for(size_t i = 0; i != final_bytes - BS; ++i)
+         std::swap(last[i], last[i + BS]);
+
+      xor_buf(last, tweak(), BS);
+      cipher().decrypt(last);
+      xor_buf(last, tweak(), BS);
+
+      buffer += last;
+      }
+   }
+
+}