Initial checkin1.5.6

1 files changed, 136 insertions, 0 deletions

diff --git a/src/x931_rng.cpp b/src/x931_rng.cpp
new file mode 100644
index 000000000..ab16c7bba
--- /dev/null
+++ b/src/x931_rng.cpp
@@ -0,0 +1,136 @@
+/*************************************************
+* ANSI X9.31 RNG Source File                     *
+* (C) 1999-2006 The Botan Project                *
+*************************************************/
+
+#include <botan/x931_rng.h>
+#include <botan/lookup.h>
+#include <botan/randpool.h>
+#include <botan/bit_ops.h>
+#include <algorithm>
+
+namespace Botan {
+
+/*************************************************
+* Generate a buffer of random bytes              *
+*************************************************/
+void ANSI_X931_RNG::randomize(byte out[], u32bit length) throw(PRNG_Unseeded)
+   {
+   if(!is_seeded())
+      throw PRNG_Unseeded(name());
+
+   while(length)
+      {
+      const u32bit copied = std::min(length, R.size() - position);
+
+      copy_mem(out, R + position, copied);
+      out += copied;
+      length -= copied;
+      position += copied;
+
+      if(position == R.size())
+         {
+         update_buffer();
+         position = 0;
+         }
+      }
+   }
+
+/*************************************************
+* Refill the internal state                      *
+*************************************************/
+void ANSI_X931_RNG::update_buffer()
+   {
+   const u32bit BLOCK_SIZE = cipher->BLOCK_SIZE;
+
+   SecureVector<byte> DT(BLOCK_SIZE);
+
+   prng->randomize(DT, DT.size());
+   cipher->encrypt(DT);
+
+   xor_buf(R, V, DT, BLOCK_SIZE);
+   cipher->encrypt(R);
+
+   xor_buf(V, R, DT, BLOCK_SIZE);
+   cipher->encrypt(V);
+   }
+
+/*************************************************
+* Add entropy to internal state                  *
+*************************************************/
+void ANSI_X931_RNG::add_randomness(const byte data[], u32bit length)
+   {
+   prng->add_entropy(data, length);
+
+   if(is_seeded())
+      {
+      SecureVector<byte> key(cipher->MAXIMUM_KEYLENGTH);
+      prng->randomize(key, key.size());
+      cipher->set_key(key, key.size());
+
+      prng->randomize(V, V.size());
+
+      update_buffer();
+      }
+   }
+
+/*************************************************
+* Check if the the PRNG is seeded                *
+*************************************************/
+bool ANSI_X931_RNG::is_seeded() const
+   {
+   return prng->is_seeded();
+   }
+
+/*************************************************
+* Clear memory of sensitive data                 *
+*************************************************/
+void ANSI_X931_RNG::clear() throw()
+   {
+   cipher->clear();
+   prng->clear();
+   R.clear();
+   V.clear();
+
+   position = 0;
+   }
+
+/*************************************************
+* Return the name of this type                   *
+*************************************************/
+std::string ANSI_X931_RNG::name() const
+   {
+   return "X9.31(" + cipher->name() + ")";
+   }
+
+/*************************************************
+* ANSI X931 RNG Constructor                      *
+*************************************************/
+ANSI_X931_RNG::ANSI_X931_RNG(const std::string& cipher_name,
+                             RandomNumberGenerator* prng_ptr)
+   {
+   if(cipher_name == "")
+      cipher = get_block_cipher("AES-256");
+   else
+      cipher = get_block_cipher(cipher_name);
+
+   const u32bit BLOCK_SIZE = cipher->BLOCK_SIZE;
+
+   V.create(BLOCK_SIZE);
+   R.create(BLOCK_SIZE);
+
+   prng = (prng_ptr ? prng_ptr : new Randpool);
+
+   position = 0;
+   }
+
+/*************************************************
+* ANSI X931 RNG Destructor                       *
+*************************************************/
+ANSI_X931_RNG::~ANSI_X931_RNG()
+   {
+   delete cipher;
+   delete prng;
+   }
+
+}