Make XTS a Transformation under src/modes

Move AEAD modes to src/modes/aead

Add filters for Transformations (based on original AEAD filters)

12 files changed, 1361 insertions, 0 deletions

diff --git a/src/modes/aead/aead.cpp b/src/modes/aead/aead.cpp
new file mode 100644
index 000000000..1ec7b4a4a
--- /dev/null
+++ b/src/modes/aead/aead.cpp
@@ -0,0 +1,78 @@
+/*
+* Interface for AEAD modes
+* (C) 2013 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#include <botan/aead.h>
+#include <botan/libstate.h>
+
+#if defined(BOTAN_HAS_AEAD_EAX)
+  #include <botan/eax.h>
+#endif
+
+#if defined(BOTAN_HAS_AEAD_GCM)
+  #include <botan/gcm.h>
+#endif
+
+#if defined(BOTAN_HAS_AEAD_OCB)
+  #include <botan/ocb.h>
+#endif
+
+namespace Botan {
+
+AEAD_Mode* get_aead(const std::string& algo_spec, Cipher_Dir direction)
+   {
+   Algorithm_Factory& af = global_state().algorithm_factory();
+
+   const std::vector<std::string> algo_parts = split_on(algo_spec, '/');
+   if(algo_parts.empty())
+      throw Invalid_Algorithm_Name(algo_spec);
+
+   if(algo_parts.size() < 2)
+      return nullptr;
+
+   const std::string cipher_name = algo_parts[0];
+   const std::string mode_name = algo_parts[1];
+
+   const size_t tag_size = 16; // default for all current AEAD
+
+   const BlockCipher* cipher = af.prototype_block_cipher(cipher_name);
+   if(!cipher)
+      return nullptr;
+
+#if defined(BOTAN_HAS_AEAD_EAX)
+   if(mode_name == "EAX")
+      {
+      if(direction == ENCRYPTION)
+         return new EAX_Encryption(cipher->clone(), tag_size);
+      else
+         return new EAX_Decryption(cipher->clone(), tag_size);
+      }
+#endif
+
+#if defined(BOTAN_HAS_AEAD_GCM)
+   if(mode_name == "GCM")
+      {
+      if(direction == ENCRYPTION)
+         return new GCM_Encryption(cipher->clone(), tag_size);
+      else
+         return new GCM_Decryption(cipher->clone(), tag_size);
+      }
+#endif
+
+#if defined(BOTAN_HAS_AEAD_OCB)
+   if(mode_name == "OCB")
+      {
+      if(direction == ENCRYPTION)
+         return new OCB_Encryption(cipher->clone(), tag_size);
+      else
+         return new OCB_Decryption(cipher->clone(), tag_size);
+      }
+#endif
+
+   return nullptr;
+   }
+
+}
diff --git a/src/modes/aead/aead.h b/src/modes/aead/aead.h
new file mode 100644
index 000000000..97f156d60
--- /dev/null
+++ b/src/modes/aead/aead.h
@@ -0,0 +1,59 @@
+/*
+* Interface for AEAD modes
+* (C) 2013 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#ifndef BOTAN_AEAD_MODE_H__
+#define BOTAN_AEAD_MODE_H__
+
+#include <botan/transform.h>
+
+namespace Botan {
+
+/**
+* Interface for AEAD (Authenticated Encryption with Associated Data)
+* modes. These modes provide both encryption and message
+* authentication, and can authenticate additional per-message data
+* which is not included in the ciphertext (for instance a sequence
+* number).
+*/
+class AEAD_Mode : public Transformation
+   {
+   public:
+      /**
+      * Set associated data that is not included in the ciphertext but
+      * that should be authenticated. Must be called after set_key
+      * and before finish.
+      *
+      * Unless reset by another call, the associated data is kept
+      * between messages. Thus, if the AD does not change, calling
+      * once (after set_key) is the optimum.
+      *
+      * @param ad the associated data
+      * @param ad_len length of add in bytes
+      */
+      virtual void set_associated_data(const byte ad[], size_t ad_len) = 0;
+
+      template<typename Alloc>
+      void set_associated_data_vec(const std::vector<byte, Alloc>& ad)
+         {
+         set_associated_data(&ad[0], ad.size());
+         }
+
+      /**
+      * Default AEAD nonce size (a commonly supported value among AEAD
+      * modes, and, large enough that random collisions are unlikely).
+      */
+      size_t default_nonce_size() const override { return 12; }
+   };
+
+/**
+* Get an AEAD mode by name (eg "AES-128/GCM" or "Serpent/EAX")
+*/
+BOTAN_DLL AEAD_Mode* get_aead(const std::string& name, Cipher_Dir direction);
+
+}
+
+#endif
diff --git a/src/modes/aead/eax/eax.cpp b/src/modes/aead/eax/eax.cpp
new file mode 100644
index 000000000..c6aaa9e85
--- /dev/null
+++ b/src/modes/aead/eax/eax.cpp
@@ -0,0 +1,170 @@
+/*
+* EAX Mode Encryption
+* (C) 1999-2007 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#include <botan/eax.h>
+#include <botan/cmac.h>
+#include <botan/ctr.h>
+#include <botan/parsing.h>
+#include <botan/internal/xor_buf.h>
+#include <algorithm>
+
+namespace Botan {
+
+namespace {
+
+/*
+* EAX MAC-based PRF
+*/
+secure_vector<byte> eax_prf(byte tag, size_t block_size,
+                           MessageAuthenticationCode& mac,
+                           const byte in[], size_t length)
+   {
+   for(size_t i = 0; i != block_size - 1; ++i)
+      mac.update(0);
+   mac.update(tag);
+   mac.update(in, length);
+   return mac.final();
+   }
+
+}
+
+/*
+* EAX_Mode Constructor
+*/
+EAX_Mode::EAX_Mode(BlockCipher* cipher, size_t tag_size) :
+   m_tag_size(tag_size),
+   m_cipher(cipher),
+   m_ctr(new CTR_BE(m_cipher->clone())),
+   m_cmac(new CMAC(m_cipher->clone()))
+   {
+   if(tag_size < 8 || tag_size > m_cmac->output_length())
+      throw Invalid_Argument(name() + ": Bad tag size " + std::to_string(tag_size));
+   }
+
+void EAX_Mode::clear()
+   {
+   m_cipher.reset();
+   m_ctr.reset();
+   m_cmac.reset();
+   zeroise(m_ad_mac);
+   zeroise(m_nonce_mac);
+   }
+
+std::string EAX_Mode::name() const
+   {
+   return (m_cipher->name() + "/EAX");
+   }
+
+size_t EAX_Mode::update_granularity() const
+   {
+   return 8 * m_cipher->parallel_bytes();
+   }
+
+Key_Length_Specification EAX_Mode::key_spec() const
+   {
+   return m_cipher->key_spec();
+   }
+
+/*
+* Set the EAX key
+*/
+void EAX_Mode::key_schedule(const byte key[], size_t length)
+   {
+   /*
+   * These could share the key schedule, which is one nice part of EAX,
+   * but it's much easier to ignore that here...
+   */
+   m_ctr->set_key(key, length);
+   m_cmac->set_key(key, length);
+
+   m_ad_mac = eax_prf(1, block_size(), *m_cmac, nullptr, 0);
+   }
+
+/*
+* Set the EAX associated data
+*/
+void EAX_Mode::set_associated_data(const byte ad[], size_t length)
+   {
+   m_ad_mac = eax_prf(1, block_size(), *m_cmac, ad, length);
+   }
+
+secure_vector<byte> EAX_Mode::start(const byte nonce[], size_t nonce_len)
+   {
+   if(!valid_nonce_length(nonce_len))
+      throw Invalid_IV_Length(name(), nonce_len);
+
+   m_nonce_mac = eax_prf(0, block_size(), *m_cmac, nonce, nonce_len);
+
+   m_ctr->set_iv(&m_nonce_mac[0], m_nonce_mac.size());
+
+   for(size_t i = 0; i != block_size() - 1; ++i)
+      m_cmac->update(0);
+   m_cmac->update(2);
+
+   return secure_vector<byte>();
+   }
+
+void EAX_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];
+
+   m_ctr->cipher(buf, buf, sz);
+   m_cmac->update(buf, sz);
+   }
+
+void EAX_Encryption::finish(secure_vector<byte>& buffer, size_t offset)
+   {
+   update(buffer, offset);
+
+   secure_vector<byte> data_mac = m_cmac->final();
+   xor_buf(data_mac, m_nonce_mac, data_mac.size());
+   xor_buf(data_mac, m_ad_mac, data_mac.size());
+
+   buffer += std::make_pair(&data_mac[0], tag_size());
+   }
+
+void EAX_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];
+
+   m_cmac->update(buf, sz);
+   m_ctr->cipher(buf, buf, sz);
+   }
+
+void EAX_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 >= tag_size(), "Have the tag as part of final input");
+
+   const size_t remaining = sz - tag_size();
+
+   if(remaining)
+      {
+      m_cmac->update(buf, remaining);
+      m_ctr->cipher(buf, buf, remaining);
+      }
+
+   const byte* included_tag = &buf[remaining];
+
+   secure_vector<byte> mac = m_cmac->final();
+   mac ^= m_nonce_mac;
+   mac ^= m_ad_mac;
+
+   if(!same_mem(&mac[0], included_tag, tag_size()))
+      throw Integrity_Failure("EAX tag check failed");
+
+   buffer.resize(offset + remaining);
+   }
+
+}
diff --git a/src/modes/aead/eax/eax.h b/src/modes/aead/eax/eax.h
new file mode 100644
index 000000000..6815e3ce0
--- /dev/null
+++ b/src/modes/aead/eax/eax.h
@@ -0,0 +1,114 @@
+/*
+* EAX Mode
+* (C) 1999-2007,2013 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#ifndef BOTAN_AEAD_EAX_H__
+#define BOTAN_AEAD_EAX_H__
+
+#include <botan/aead.h>
+#include <botan/block_cipher.h>
+#include <botan/stream_cipher.h>
+#include <botan/mac.h>
+#include <memory>
+
+namespace Botan {
+
+/**
+* EAX base class
+*/
+class BOTAN_DLL EAX_Mode : public AEAD_Mode
+   {
+   public:
+      secure_vector<byte> start(const byte nonce[], size_t nonce_len) override;
+
+      void set_associated_data(const byte ad[], size_t ad_len) override;
+
+      std::string name() const override;
+
+      size_t update_granularity() const;
+
+      Key_Length_Specification key_spec() const override;
+
+      // EAX supports arbitrary nonce lengths
+      bool valid_nonce_length(size_t) const override { return true; }
+
+      void clear();
+   protected:
+      void key_schedule(const byte key[], size_t length) override;
+
+      /**
+      * @param cipher the cipher to use
+      * @param tag_size is how big the auth tag will be
+      */
+      EAX_Mode(BlockCipher* cipher, size_t tag_size);
+
+      size_t tag_size() const { return m_tag_size; }
+
+      size_t block_size() const { return m_cipher->block_size(); }
+
+      size_t m_tag_size;
+
+      std::unique_ptr<BlockCipher> m_cipher;
+      std::unique_ptr<StreamCipher> m_ctr;
+      std::unique_ptr<MessageAuthenticationCode> m_cmac;
+
+      secure_vector<byte> m_ad_mac;
+
+      secure_vector<byte> m_nonce_mac;
+   };
+
+/**
+* EAX Encryption
+*/
+class BOTAN_DLL EAX_Encryption : public EAX_Mode
+   {
+   public:
+      /**
+      * @param cipher a 128-bit block cipher
+      * @param tag_size is how big the auth tag will be
+      */
+      EAX_Encryption(BlockCipher* cipher, size_t tag_size = 16) :
+         EAX_Mode(cipher, tag_size) {}
+
+      size_t output_length(size_t input_length) const override
+         { return input_length + tag_size(); }
+
+      size_t minimum_final_size() const override { return 0; }
+
+      void update(secure_vector<byte>& blocks, size_t offset) override;
+
+      void finish(secure_vector<byte>& final_block, size_t offset) override;
+   };
+
+/**
+* EAX Decryption
+*/
+class BOTAN_DLL EAX_Decryption : public EAX_Mode
+   {
+   public:
+      /**
+      * @param cipher a 128-bit block cipher
+      * @param tag_size is how big the auth tag will be
+      */
+      EAX_Decryption(BlockCipher* cipher, size_t tag_size = 16) :
+         EAX_Mode(cipher, tag_size) {}
+
+      size_t output_length(size_t input_length) const override
+         {
+         BOTAN_ASSERT(input_length > tag_size(), "Sufficient input");
+         return input_length - tag_size();
+         }
+
+      size_t minimum_final_size() const override { return tag_size(); }
+
+      void update(secure_vector<byte>& blocks, size_t offset) override;
+
+      void finish(secure_vector<byte>& final_block, size_t offset) override;
+   };
+
+}
+
+#endif
diff --git a/src/modes/aead/eax/info.txt b/src/modes/aead/eax/info.txt
new file mode 100644
index 000000000..94924e682
--- /dev/null
+++ b/src/modes/aead/eax/info.txt
@@ -0,0 +1,7 @@
+define AEAD_EAX
+
+<requires>
+block
+cmac
+ctr
+</requires>
diff --git a/src/modes/aead/gcm/gcm.cpp b/src/modes/aead/gcm/gcm.cpp
new file mode 100644
index 000000000..7b8e0aa36
--- /dev/null
+++ b/src/modes/aead/gcm/gcm.cpp
@@ -0,0 +1,243 @@
+/*
+* GCM Mode Encryption
+* (C) 2013 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#include <botan/gcm.h>
+#include <botan/ctr.h>
+#include <botan/internal/xor_buf.h>
+#include <botan/loadstor.h>
+
+namespace Botan {
+
+namespace {
+
+void gcm_multiply(secure_vector<byte>& x,
+                  const secure_vector<byte>& h)
+   {
+   static const u64bit R = 0xE100000000000000;
+
+   u64bit H[2] = {
+      load_be<u64bit>(&h[0], 0),
+      load_be<u64bit>(&h[0], 1)
+   };
+
+   u64bit Z[2] = { 0, 0 };
+
+   // Both CLMUL and SSE2 versions would be useful
+
+   for(size_t i = 0; i != 2; ++i)
+      {
+      const u64bit X = load_be<u64bit>(&x[0], i);
+
+      for(size_t j = 0; j != 64; ++j)
+         {
+         if((X >> (63-j)) & 1)
+            {
+            Z[0] ^= H[0];
+            Z[1] ^= H[1];
+            }
+
+         const u64bit r = (H[1] & 1) ? R : 0;
+
+         H[1] = (H[0] << 63) | (H[1] >> 1);
+         H[0] = (H[0] >> 1) ^ r;
+         }
+      }
+
+   store_be<u64bit>(&x[0], Z[0], Z[1]);
+   }
+
+void ghash_update(const secure_vector<byte>& H,
+                  secure_vector<byte>& ghash,
+                  const byte input[], size_t length)
+   {
+   const size_t BS = 16;
+
+   /*
+   This assumes if less than block size input then we're just on the
+   final block and should pad with zeros
+   */
+   while(length)
+      {
+      const size_t to_proc = std::min(length, BS);
+
+      xor_buf(&ghash[0], &input[0], to_proc);
+
+      gcm_multiply(ghash, H);
+
+      input += to_proc;
+      length -= to_proc;
+      }
+   }
+
+void ghash_finalize(const secure_vector<byte>& H,
+                    secure_vector<byte>& ghash,
+                    size_t ad_len, size_t text_len)
+   {
+   secure_vector<byte> final_block(16);
+   store_be<u64bit>(&final_block[0], 8*ad_len, 8*text_len);
+   ghash_update(H, ghash, &final_block[0], final_block.size());
+   }
+
+}
+
+/*
+* GCM_Mode Constructor
+*/
+GCM_Mode::GCM_Mode(BlockCipher* cipher, size_t tag_size) :
+   m_tag_size(tag_size),
+   m_cipher_name(cipher->name()),
+   m_H(BS), m_H_ad(BS), m_mac(BS), m_enc_y0(BS),
+   m_ad_len(0), m_text_len(0)
+   {
+   if(cipher->block_size() != BS)
+      throw std::invalid_argument("GCM requires a 128 bit cipher so cannot be used with " +
+                                  cipher->name());
+
+   m_ctr.reset(new CTR_BE(cipher)); // CTR_BE takes ownership of cipher
+
+   if(m_tag_size < 8 || m_tag_size > 16)
+      throw Invalid_Argument(name() + ": Bad tag size " + std::to_string(m_tag_size));
+   }
+
+void GCM_Mode::clear()
+   {
+   zeroise(m_H);
+   zeroise(m_H_ad);
+   zeroise(m_mac);
+   zeroise(m_enc_y0);
+   m_ad_len = 0;
+   m_text_len = 0;
+   m_ctr.reset();
+   }
+
+std::string GCM_Mode::name() const
+   {
+   return (m_cipher_name + "/GCM");
+   }
+
+size_t GCM_Mode::update_granularity() const
+   {
+   return 4096; // CTR-BE's internal block size
+   }
+
+Key_Length_Specification GCM_Mode::key_spec() const
+   {
+   return m_ctr->key_spec();
+   }
+
+void GCM_Mode::key_schedule(const byte key[], size_t keylen)
+   {
+   m_ctr->set_key(key, keylen);
+
+   const std::vector<byte> zeros(BS);
+   m_ctr->set_iv(&zeros[0], zeros.size());
+
+   zeroise(m_H);
+   m_ctr->cipher(&m_H[0], &m_H[0], m_H.size());
+   }
+
+void GCM_Mode::set_associated_data(const byte ad[], size_t ad_len)
+   {
+   zeroise(m_H_ad);
+
+   ghash_update(m_H, m_H_ad, ad, ad_len);
+   m_ad_len = ad_len;
+   }
+
+secure_vector<byte> GCM_Mode::start(const byte nonce[], size_t nonce_len)
+   {
+   if(!valid_nonce_length(nonce_len))
+      throw Invalid_IV_Length(name(), nonce_len);
+
+   secure_vector<byte> y0(BS);
+
+   if(nonce_len == 12)
+      {
+      copy_mem(&y0[0], nonce, nonce_len);
+      y0[15] = 1;
+      }
+   else
+      {
+      ghash_update(m_H, y0, nonce, nonce_len);
+      ghash_finalize(m_H, y0, 0, nonce_len);
+      }
+
+   m_ctr->set_iv(&y0[0], y0.size());
+
+   zeroise(m_enc_y0);
+   m_ctr->encipher(m_enc_y0);
+
+   m_text_len = 0;
+   m_mac = m_H_ad;
+
+   return secure_vector<byte>();
+   }
+
+void GCM_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];
+
+   m_ctr->cipher(buf, buf, sz);
+   ghash_update(m_H, m_mac, buf, sz);
+   m_text_len += sz;
+   }
+
+void GCM_Encryption::finish(secure_vector<byte>& buffer, size_t offset)
+   {
+   update(buffer, offset);
+
+   ghash_finalize(m_H, m_mac, m_ad_len, m_text_len);
+
+   m_mac ^= m_enc_y0;
+
+   buffer += std::make_pair(&m_mac[0], tag_size());
+   }
+
+void GCM_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];
+
+   ghash_update(m_H, m_mac, buf, sz);
+   m_ctr->cipher(buf, buf, sz);
+   m_text_len += sz;
+   }
+
+void GCM_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 >= tag_size(), "Have the tag as part of final input");
+
+   const size_t remaining = sz - tag_size();
+
+   // handle any final input before the tag
+   if(remaining)
+      {
+      ghash_update(m_H, m_mac, buf, remaining);
+      m_ctr->cipher(buf, buf, remaining);
+      m_text_len += remaining;
+      }
+
+   ghash_finalize(m_H, m_mac, m_ad_len, m_text_len);
+
+   m_mac ^= m_enc_y0;
+
+   const byte* included_tag = &buffer[remaining];
+
+   if(!same_mem(&m_mac[0], included_tag, tag_size()))
+      throw Integrity_Failure("GCM tag check failed");
+
+   buffer.resize(offset + remaining);
+   }
+
+}
diff --git a/src/modes/aead/gcm/gcm.h b/src/modes/aead/gcm/gcm.h
new file mode 100644
index 000000000..e1479c27f
--- /dev/null
+++ b/src/modes/aead/gcm/gcm.h
@@ -0,0 +1,109 @@
+/*
+* GCM Mode
+* (C) 2013 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#ifndef BOTAN_AEAD_GCM_H__
+#define BOTAN_AEAD_GCM_H__
+
+#include <botan/aead.h>
+#include <botan/block_cipher.h>
+#include <botan/stream_cipher.h>
+#include <memory>
+
+namespace Botan {
+
+/**
+* GCM Mode
+*/
+class BOTAN_DLL GCM_Mode : public AEAD_Mode
+   {
+   public:
+      secure_vector<byte> start(const byte nonce[], size_t nonce_len) override;
+
+      void set_associated_data(const byte ad[], size_t ad_len) override;
+
+      std::string name() const override;
+
+      size_t update_granularity() const;
+
+      Key_Length_Specification key_spec() const override;
+
+      // GCM supports arbitrary nonce lengths
+      bool valid_nonce_length(size_t) const override { return true; }
+
+      void clear();
+   protected:
+      void key_schedule(const byte key[], size_t length) override;
+
+      GCM_Mode(BlockCipher* cipher, size_t tag_size);
+
+      size_t tag_size() const { return m_tag_size; }
+
+      static const size_t BS = 16;
+
+      const size_t m_tag_size;
+      const std::string m_cipher_name;
+
+      std::unique_ptr<StreamCipher> m_ctr;
+      secure_vector<byte> m_H;
+      secure_vector<byte> m_H_ad;
+      secure_vector<byte> m_mac;
+      secure_vector<byte> m_enc_y0;
+      size_t m_ad_len, m_text_len;
+   };
+
+/**
+* GCM Encryption
+*/
+class BOTAN_DLL GCM_Encryption : public GCM_Mode
+   {
+   public:
+      /**
+      * @param cipher the 128 bit block cipher to use
+      * @param tag_size is how big the auth tag will be
+      */
+      GCM_Encryption(BlockCipher* cipher, size_t tag_size = 16) :
+         GCM_Mode(cipher, tag_size) {}
+
+      size_t output_length(size_t input_length) const override
+         { return input_length + tag_size(); }
+
+      size_t minimum_final_size() const override { return 0; }
+
+      void update(secure_vector<byte>& blocks, size_t offset) override;
+
+      void finish(secure_vector<byte>& final_block, size_t offset) override;
+   };
+
+/**
+* GCM Decryption
+*/
+class BOTAN_DLL GCM_Decryption : public GCM_Mode
+   {
+   public:
+      /**
+      * @param cipher the 128 bit block cipher to use
+      * @param tag_size is how big the auth tag will be
+      */
+      GCM_Decryption(BlockCipher* cipher, size_t tag_size = 16) :
+         GCM_Mode(cipher, tag_size) {}
+
+      size_t output_length(size_t input_length) const override
+         {
+         BOTAN_ASSERT(input_length > tag_size(), "Sufficient input");
+         return input_length - tag_size();
+         }
+
+      size_t minimum_final_size() const override { return tag_size(); }
+
+      void update(secure_vector<byte>& blocks, size_t offset) override;
+
+      void finish(secure_vector<byte>& final_block, size_t offset) override;
+   };
+
+}
+
+#endif
diff --git a/src/modes/aead/gcm/info.txt b/src/modes/aead/gcm/info.txt
new file mode 100644
index 000000000..698cd0803
--- /dev/null
+++ b/src/modes/aead/gcm/info.txt
@@ -0,0 +1,6 @@
+define AEAD_GCM
+
+<requires>
+block
+ctr
+</requires>
diff --git a/src/modes/aead/info.txt b/src/modes/aead/info.txt
new file mode 100644
index 000000000..c2985ea85
--- /dev/null
+++ b/src/modes/aead/info.txt
@@ -0,0 +1 @@
+define AEAD_MODES
diff --git a/src/modes/aead/ocb/info.txt b/src/modes/aead/ocb/info.txt
new file mode 100644
index 000000000..8d6a93ed9
--- /dev/null
+++ b/src/modes/aead/ocb/info.txt
@@ -0,0 +1,6 @@
+define AEAD_OCB
+
+<requires>
+block
+cmac
+</requires>
diff --git a/src/modes/aead/ocb/ocb.cpp b/src/modes/aead/ocb/ocb.cpp
new file mode 100644
index 000000000..4cbd8bde8
--- /dev/null
+++ b/src/modes/aead/ocb/ocb.cpp
@@ -0,0 +1,444 @@
+/*
+* OCB Mode
+* (C) 2013 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#include <botan/ocb.h>
+#include <botan/cmac.h>
+#include <botan/internal/xor_buf.h>
+#include <botan/internal/bit_ops.h>
+#include <algorithm>
+
+namespace Botan {
+
+// Has to be in Botan namespace so unique_ptr can reference it
+class L_computer
+   {
+   public:
+      L_computer(const BlockCipher& cipher)
+         {
+         m_L_star.resize(cipher.block_size());
+         cipher.encrypt(m_L_star);
+         m_L_dollar = poly_double(star());
+         m_L.push_back(poly_double(dollar()));
+         }
+
+      const secure_vector<byte>& star() const { return m_L_star; }
+
+      const secure_vector<byte>& dollar() const { return m_L_dollar; }
+
+      const secure_vector<byte>& operator()(size_t i) const { return get(i); }
+
+      const secure_vector<byte>& get(size_t i) const
+         {
+         while(m_L.size() <= i)
+            m_L.push_back(poly_double(m_L.back()));
+
+         return m_L.at(i);
+         }
+
+   private:
+      secure_vector<byte> poly_double(const secure_vector<byte>& in) const
+         {
+         return CMAC::poly_double(in, 0x87);
+         }
+
+      secure_vector<byte> m_L_dollar, m_L_star;
+      mutable std::vector<secure_vector<byte>> m_L;
+   };
+
+class Nonce_State
+   {
+   public:
+      Nonce_State(const BlockCipher& cipher) : m_cipher(cipher) {}
+
+      secure_vector<byte> update_nonce(const byte nonce[],
+                                       size_t nonce_len);
+   private:
+      const BlockCipher& m_cipher;
+      secure_vector<byte> m_last_nonce;
+      secure_vector<byte> m_stretch;
+   };
+
+secure_vector<byte>
+Nonce_State::update_nonce(const byte nonce[], size_t nonce_len)
+   {
+   const size_t BS = 16;
+
+   BOTAN_ASSERT(nonce_len < BS, "Nonce is less than 128 bits");
+
+   secure_vector<byte> nonce_buf(BS);
+
+   copy_mem(&nonce_buf[BS - nonce_len], nonce, nonce_len);
+   nonce_buf[BS - nonce_len - 1] = 1;
+
+   const byte bottom = nonce_buf[15] & 0x3F;
+   nonce_buf[15] &= 0xC0;
+
+   const bool need_new_stretch = (m_last_nonce != nonce_buf);
+
+   if(need_new_stretch)
+      {
+      m_last_nonce = nonce_buf;
+
+      m_cipher.encrypt(nonce_buf);
+
+      for(size_t i = 0; i != 8; ++i)
+         nonce_buf.push_back(nonce_buf[i] ^ nonce_buf[i+1]);
+
+      m_stretch = nonce_buf;
+      }
+
+   // now set the offset from stretch and bottom
+
+   const size_t shift_bytes = bottom / 8;
+   const size_t shift_bits  = bottom % 8;
+
+   secure_vector<byte> offset(BS);
+   for(size_t i = 0; i != BS; ++i)
+      {
+      offset[i]  = (m_stretch[i+shift_bytes] << shift_bits);
+      offset[i] |= (m_stretch[i+shift_bytes+1] >> (8-shift_bits));
+      }
+
+   return offset;
+   }
+
+namespace {
+
+/*
+* OCB's HASH
+*/
+secure_vector<byte> ocb_hash(const L_computer& L,
+                             const BlockCipher& cipher,
+                             const byte ad[], size_t ad_len)
+   {
+   const size_t BS = cipher.block_size();
+
+   secure_vector<byte> sum(BS);
+   secure_vector<byte> offset(BS);
+
+   secure_vector<byte> buf(BS);
+
+   const size_t ad_blocks = (ad_len / BS);
+   const size_t ad_remainder = (ad_len % BS);
+
+   for(size_t i = 0; i != ad_blocks; ++i)
+      {
+      // this loop could run in parallel
+      offset ^= L(ctz(i+1));
+
+      buf = offset;
+      xor_buf(&buf[0], &ad[BS*i], BS);
+
+      cipher.encrypt(buf);
+
+      sum ^= buf;
+      }
+
+   if(ad_remainder)
+      {
+      offset ^= L.star();
+
+      buf = offset;
+      xor_buf(&buf[0], &ad[BS*ad_blocks], ad_remainder);
+      buf[ad_len % BS] ^= 0x80;
+
+      cipher.encrypt(buf);
+
+      sum ^= buf;
+      }
+
+   return sum;
+   }
+
+}
+
+OCB_Mode::OCB_Mode(BlockCipher* cipher, size_t tag_size) :
+   m_cipher(cipher),
+   m_tag_size(tag_size),
+   m_ad_hash(BS), m_offset(BS), m_checksum(BS)
+   {
+   if(m_cipher->block_size() != BS)
+      throw std::invalid_argument("OCB requires a 128 bit cipher so cannot be used with " +
+                                  m_cipher->name());
+
+   if(m_tag_size != 16) // fixme: 64, 96 bits also supported
+      throw std::invalid_argument("OCB cannot produce a " + std::to_string(m_tag_size) +
+                                  " byte tag");
+
+   }
+
+OCB_Mode::~OCB_Mode() { /* for unique_ptr destructor */ }
+
+void OCB_Mode::clear()
+   {
+   m_cipher.reset();
+   m_L.reset();
+   zeroise(m_ad_hash);
+   zeroise(m_offset);
+   zeroise(m_checksum);
+   }
+
+bool OCB_Mode::valid_nonce_length(size_t length) const
+   {
+   return (length > 0 && length < 16);
+   }
+
+std::string OCB_Mode::name() const
+   {
+   return m_cipher->name() + "/OCB"; // include tag size
+   }
+
+size_t OCB_Mode::update_granularity() const
+   {
+   return 8 * m_cipher->parallel_bytes();
+   }
+
+Key_Length_Specification OCB_Mode::key_spec() const
+   {
+   return m_cipher->key_spec();
+   }
+
+void OCB_Mode::key_schedule(const byte key[], size_t length)
+   {
+   m_cipher->set_key(key, length);
+   m_L.reset(new L_computer(*m_cipher));
+   m_nonce_state.reset(new Nonce_State(*m_cipher));
+   }
+
+void OCB_Mode::set_associated_data(const byte ad[], size_t ad_len)
+   {
+   BOTAN_ASSERT(m_L, "A key was set");
+   m_ad_hash = ocb_hash(*m_L, *m_cipher, &ad[0], ad_len);
+   }
+
+secure_vector<byte> OCB_Mode::start(const byte nonce[], size_t nonce_len)
+   {
+   if(!valid_nonce_length(nonce_len))
+      throw Invalid_IV_Length(name(), nonce_len);
+
+   BOTAN_ASSERT(m_nonce_state, "A key was set");
+
+   m_offset = m_nonce_state->update_nonce(nonce, nonce_len);
+   zeroise(m_checksum);
+   m_block_index = 0;
+
+   return secure_vector<byte>();
+   }
+
+void OCB_Encryption::encrypt(byte buffer[], size_t blocks)
+   {
+   const L_computer& L = *m_L; // convenient name
+
+   const size_t par_bytes = m_cipher->parallel_bytes();
+
+   BOTAN_ASSERT(par_bytes % BS == 0, "Cipher is parallel in full blocks");
+
+   const size_t par_blocks = par_bytes / BS;
+
+   secure_vector<byte> csum_accum(par_bytes);
+   secure_vector<byte> offsets(par_bytes);
+
+   size_t blocks_left = blocks;
+
+   while(blocks_left)
+      {
+      const size_t proc_blocks = std::min(blocks_left, par_blocks);
+      const size_t proc_bytes = proc_blocks * BS;
+
+      for(size_t i = 0; i != proc_blocks; ++i)
+         { // could be done in parallel
+         m_offset ^= L(ctz(++m_block_index));
+         copy_mem(&offsets[BS*i], &m_offset[0], BS);
+         }
+
+      xor_buf(&csum_accum[0], &buffer[0], proc_bytes);
+
+      xor_buf(&buffer[0], &offsets[0], proc_bytes);
+
+      m_cipher->encrypt_n(&buffer[0], &buffer[0], proc_blocks);
+
+      xor_buf(&buffer[0], &offsets[0], proc_bytes);
+
+      buffer += proc_bytes;
+      blocks_left -= proc_blocks;
+      }
+
+   // fold into checksum
+   for(size_t i = 0; i != csum_accum.size(); ++i)
+      m_checksum[i % BS] ^= csum_accum[i];
+   }
+
+void OCB_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];
+
+   BOTAN_ASSERT(sz % BS == 0, "Input length is an even number of blocks");
+
+   encrypt(buf, sz / BS);
+   }
+
+void OCB_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];
+
+   if(sz)
+      {
+      const size_t final_full_blocks = sz / BS;
+      const size_t remainder_bytes = sz - (final_full_blocks * BS);
+
+      encrypt(buf, final_full_blocks);
+
+      if(remainder_bytes)
+         {
+         BOTAN_ASSERT(remainder_bytes < BS, "Only a partial block left");
+         byte* remainder = &buf[sz - remainder_bytes];
+
+         xor_buf(&m_checksum[0], &remainder[0], remainder_bytes);
+         m_checksum[remainder_bytes] ^= 0x80;
+
+         m_offset ^= m_L->star(); // Offset_*
+
+         secure_vector<byte> buf(BS);
+         m_cipher->encrypt(m_offset, buf);
+         xor_buf(&remainder[0], &buf[0], remainder_bytes);
+         }
+      }
+
+   // now compute the tag
+   secure_vector<byte> mac = m_offset;
+   mac ^= m_checksum;
+   mac ^= m_L->dollar();
+
+   m_cipher->encrypt(mac);
+
+   mac ^= m_ad_hash;
+
+   buffer += std::make_pair(&mac[0], tag_size());
+
+   zeroise(m_checksum);
+   zeroise(m_offset);
+   m_block_index = 0;
+   }
+
+void OCB_Decryption::decrypt(byte buffer[], size_t blocks)
+   {
+   const L_computer& L = *m_L; // convenient name
+
+   const size_t par_bytes = m_cipher->parallel_bytes();
+
+   BOTAN_ASSERT(par_bytes % BS == 0, "Cipher is parallel in full blocks");
+
+   const size_t par_blocks = par_bytes / BS;
+
+   secure_vector<byte> csum_accum(par_bytes);
+   secure_vector<byte> offsets(par_bytes);
+
+   size_t blocks_left = blocks;
+
+   while(blocks_left)
+      {
+      const size_t proc_blocks = std::min(blocks_left, par_blocks);
+      const size_t proc_bytes = proc_blocks * BS;
+
+      for(size_t i = 0; i != proc_blocks; ++i)
+         { // could be done in parallel
+         m_offset ^= L(ctz(++m_block_index));
+         copy_mem(&offsets[BS*i], &m_offset[0], BS);
+         }
+
+      xor_buf(&buffer[0], &offsets[0], proc_bytes);
+
+      m_cipher->decrypt_n(&buffer[0], &buffer[0], proc_blocks);
+
+      xor_buf(&buffer[0], &offsets[0], proc_bytes);
+
+      xor_buf(&csum_accum[0], &buffer[0], proc_bytes);
+
+      buffer += proc_bytes;
+      blocks_left -= proc_blocks;
+      }
+
+   // fold into checksum
+   for(size_t i = 0; i != csum_accum.size(); ++i)
+      m_checksum[i % BS] ^= csum_accum[i];
+   }
+
+void OCB_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];
+
+   BOTAN_ASSERT(sz % BS == 0, "Input length is an even number of blocks");
+
+   decrypt(buf, sz / BS);
+   }
+
+void OCB_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 >= tag_size(), "We have the tag");
+
+   const size_t remaining = sz - tag_size();
+
+   if(remaining)
+      {
+      const size_t final_full_blocks = remaining / BS;
+      const size_t final_bytes = remaining - (final_full_blocks * BS);
+
+      decrypt(&buf[0], final_full_blocks);
+
+      if(final_bytes)
+         {
+         BOTAN_ASSERT(final_bytes < BS, "Only a partial block left");
+
+         byte* remainder = &buf[remaining - final_bytes];
+
+         m_offset ^= m_L->star(); // Offset_*
+
+         secure_vector<byte> pad(BS);
+         m_cipher->encrypt(m_offset, pad); // P_*
+
+         xor_buf(&remainder[0], &pad[0], final_bytes);
+
+         xor_buf(&m_checksum[0], &remainder[0], final_bytes);
+         m_checksum[final_bytes] ^= 0x80;
+         }
+      }
+
+   // compute the mac
+   secure_vector<byte> mac = m_offset;
+   mac ^= m_checksum;
+   mac ^= m_L->dollar();
+
+   m_cipher->encrypt(mac);
+
+   mac ^= m_ad_hash;
+
+   // reset state
+   zeroise(m_checksum);
+   zeroise(m_offset);
+   m_block_index = 0;
+
+   // compare mac
+   const byte* included_tag = &buf[remaining];
+
+   if(!same_mem(&mac[0], included_tag, tag_size()))
+      throw Integrity_Failure("OCB tag check failed");
+
+   // remove tag from end of message
+   buffer.resize(remaining + offset);
+   }
+
+}
diff --git a/src/modes/aead/ocb/ocb.h b/src/modes/aead/ocb/ocb.h
new file mode 100644
index 000000000..ea7729348
--- /dev/null
+++ b/src/modes/aead/ocb/ocb.h
@@ -0,0 +1,124 @@
+/*
+* OCB Mode
+* (C) 2013 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#ifndef BOTAN_AEAD_OCB_H__
+#define BOTAN_AEAD_OCB_H__
+
+#include <botan/aead.h>
+#include <botan/block_cipher.h>
+#include <botan/buf_filt.h>
+#include <memory>
+
+namespace Botan {
+
+class L_computer;
+class Nonce_State;
+
+/**
+* OCB Mode (base class for OCB_Encryption and OCB_Decryption). Note
+* that OCB is patented, but is freely licensed in some circumstances.
+*
+* @see "The OCB Authenticated-Encryption Algorithm" internet draft
+        http://tools.ietf.org/html/draft-irtf-cfrg-ocb-01
+* @see Free Licenses http://www.cs.ucdavis.edu/~rogaway/ocb/license.htm
+* @see OCB home page http://www.cs.ucdavis.edu/~rogaway/ocb
+*/
+class BOTAN_DLL OCB_Mode : public AEAD_Mode
+   {
+   public:
+      secure_vector<byte> start(const byte nonce[], size_t nonce_len) override;
+
+      void set_associated_data(const byte ad[], size_t ad_len) override;
+
+      std::string name() const override;
+
+      size_t update_granularity() const;
+
+      Key_Length_Specification key_spec() const override;
+
+      bool valid_nonce_length(size_t) const override;
+
+      void clear();
+
+      ~OCB_Mode();
+   protected:
+      static const size_t BS = 16; // intrinsic to OCB definition
+
+      /**
+      * @param cipher the 128-bit block cipher to use
+      * @param tag_size is how big the auth tag will be
+      */
+      OCB_Mode(BlockCipher* cipher, size_t tag_size);
+
+      void key_schedule(const byte key[], size_t length) override;
+
+      size_t tag_size() const { return m_tag_size; }
+
+      // fixme make these private
+      std::unique_ptr<BlockCipher> m_cipher;
+      std::unique_ptr<L_computer> m_L;
+
+      size_t m_tag_size = 0;
+      size_t m_block_index = 0;
+
+      secure_vector<byte> m_ad_hash;
+      secure_vector<byte> m_offset;
+      secure_vector<byte> m_checksum;
+   private:
+      std::unique_ptr<Nonce_State> m_nonce_state;
+   };
+
+class BOTAN_DLL OCB_Encryption : public OCB_Mode
+   {
+   public:
+      /**
+      * @param cipher the 128-bit block cipher to use
+      * @param tag_size is how big the auth tag will be
+      */
+      OCB_Encryption(BlockCipher* cipher, size_t tag_size = 16) :
+         OCB_Mode(cipher, tag_size) {}
+
+      size_t output_length(size_t input_length) const override
+         { return input_length + tag_size(); }
+
+      size_t minimum_final_size() const override { return 0; }
+
+      void update(secure_vector<byte>& blocks, size_t offset) override;
+
+      void finish(secure_vector<byte>& final_block, size_t offset) override;
+   private:
+      void encrypt(byte input[], size_t blocks);
+   };
+
+class BOTAN_DLL OCB_Decryption : public OCB_Mode
+   {
+   public:
+      /**
+      * @param cipher the 128-bit block cipher to use
+      * @param tag_size is how big the auth tag will be
+      */
+      OCB_Decryption(BlockCipher* cipher, size_t tag_size = 16) :
+         OCB_Mode(cipher, tag_size) {}
+
+      size_t output_length(size_t input_length) const override
+         {
+         BOTAN_ASSERT(input_length > tag_size(), "Sufficient input");
+         return input_length - tag_size();
+         }
+
+      size_t minimum_final_size() const override { return tag_size(); }
+
+      void update(secure_vector<byte>& blocks, size_t offset) override;
+
+      void finish(secure_vector<byte>& final_block, size_t offset) override;
+   private:
+      void decrypt(byte input[], size_t blocks);
+   };
+
+}
+
+#endif