1 files changed, 120 insertions, 0 deletions
diff --git a/src/constructs/aont/package.cpp b/src/constructs/aont/package.cpp
new file mode 100644
index 000000000..37bad46c8
--- /dev/null
+++ b/src/constructs/aont/package.cpp
@@ -0,0 +1,120 @@
+/*
+* Rivest's Package Tranform
+*
+* (C) 2009 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#include <botan/package.h>
+#include <botan/filters.h>
+#include <botan/ctr.h>
+#include <botan/loadstor.h>
+#include <botan/xor_buf.h>
+
+namespace Botan {
+
+namespace AllOrNothingTransform {
+
+void package(RandomNumberGenerator& rng,
+             BlockCipher* cipher,
+             const byte input[], u32bit input_len,
+             byte output[])
+   {
+   if(!cipher->valid_keylength(cipher->BLOCK_SIZE))
+      throw Invalid_Argument("AONT::package: Invalid cipher");
+
+   // The all-zero string which is used both as the CTR IV and as K0
+   const std::string all_zeros(cipher->BLOCK_SIZE*2, '0');
+
+   SymmetricKey package_key(rng, cipher->BLOCK_SIZE);
+
+   Pipe pipe(new StreamCipher_Filter(new CTR_BE(cipher), package_key));
+
+   pipe.process_msg(input, input_len);
+   pipe.read(output, pipe.remaining());
+
+   // Set K0 (the all zero key)
+   cipher->set_key(SymmetricKey(all_zeros));
+
+   SecureVector<byte> buf(cipher->BLOCK_SIZE);
+
+   const u32bit blocks =
+      (input_len + cipher->BLOCK_SIZE - 1) / cipher->BLOCK_SIZE;
+
+   byte* final_block = output + input_len;
+   clear_mem(final_block, cipher->BLOCK_SIZE);
+
+   // XOR the hash blocks into the final block
+   for(u32bit i = 0; i != blocks; ++i)
+      {
+      u32bit left = std::min<u32bit>(cipher->BLOCK_SIZE,
+                                     input_len - cipher->BLOCK_SIZE * i);
+
+      buf.clear();
+      copy_mem(&buf[0], output + cipher->BLOCK_SIZE * i, left);
+
+      for(u32bit j = 0; j != 4; ++j)
+         buf[cipher->BLOCK_SIZE - 1 - j] ^= get_byte(3-j, i);
+
+      cipher->encrypt(buf);
+
+      xor_buf(final_block, buf, cipher->BLOCK_SIZE);
+      }
+
+   // XOR the random package key into the final block
+   xor_buf(final_block, package_key.begin(), cipher->BLOCK_SIZE);
+   }
+
+void unpackage(BlockCipher* cipher,
+               const byte input[], u32bit input_len,
+               byte output[])
+   {
+   if(!cipher->valid_keylength(cipher->BLOCK_SIZE))
+      throw Invalid_Argument("AONT::unpackage: Invalid cipher");
+
+   if(input_len < cipher->BLOCK_SIZE)
+      throw Invalid_Argument("AONT::unpackage: Input too short");
+
+   // The all-zero string which is used both as the CTR IV and as K0
+   const std::string all_zeros(cipher->BLOCK_SIZE*2, '0');
+
+   cipher->set_key(SymmetricKey(all_zeros));
+
+   SecureVector<byte> package_key(cipher->BLOCK_SIZE);
+   SecureVector<byte> buf(cipher->BLOCK_SIZE);
+
+   // Copy the package key (masked with the block hashes)
+   copy_mem(&package_key[0],
+            input + (input_len - cipher->BLOCK_SIZE),
+            cipher->BLOCK_SIZE);
+
+   const u32bit blocks = ((input_len - 1) / cipher->BLOCK_SIZE);
+
+   // XOR the blocks into the package key bits
+   for(u32bit i = 0; i != blocks; ++i)
+      {
+      u32bit left = std::min<u32bit>(cipher->BLOCK_SIZE,
+                                     input_len - cipher->BLOCK_SIZE * (i+1));
+
+      buf.clear();
+      copy_mem(&buf[0], input + cipher->BLOCK_SIZE * i, left);
+
+      for(u32bit j = 0; j != 4; ++j)
+         buf[cipher->BLOCK_SIZE - 1 - j] ^= get_byte(3-j, i);
+
+      cipher->encrypt(buf);
+
+      xor_buf(&package_key[0], buf, cipher->BLOCK_SIZE);
+      }
+
+   Pipe pipe(new StreamCipher_Filter(new CTR_BE(cipher), package_key));
+
+   pipe.process_msg(input, input_len - cipher->BLOCK_SIZE);
+
+   pipe.read(output, pipe.remaining());
+   }
+
+}
+
+}