1 files changed, 142 insertions, 0 deletions
diff --git a/src/rng/x931_rng/x931_rng.cpp b/src/rng/x931_rng/x931_rng.cpp
new file mode 100644
index 000000000..f4b0f71a9
--- /dev/null
+++ b/src/rng/x931_rng/x931_rng.cpp
@@ -0,0 +1,142 @@
+/*************************************************
+* ANSI X9.31 RNG Source File                     *
+* (C) 1999-2008 Jack Lloyd                       *
+*************************************************/
+
+#include <botan/x931_rng.h>
+#include <botan/lookup.h>
+#include <botan/xor_buf.h>
+#include <algorithm>
+
+namespace Botan {
+
+/*************************************************
+* Generate a buffer of random bytes              *
+*************************************************/
+void ANSI_X931_RNG::randomize(byte out[], u32bit length)
+   {
+   if(!is_seeded())
+      reseed();
+
+   while(length)
+      {
+      if(position == R.size())
+         update_buffer();
+
+      const u32bit copied = std::min(length, R.size() - position);
+
+      copy_mem(out, R + position, copied);
+      out += copied;
+      length -= copied;
+      position += copied;
+      }
+   }
+
+/*************************************************
+* Refill the internal state                      *
+*************************************************/
+void ANSI_X931_RNG::update_buffer()
+   {
+   SecureVector<byte> DT(cipher->BLOCK_SIZE);
+
+   prng->randomize(DT, DT.size());
+   cipher->encrypt(DT);
+
+   xor_buf(R, V, DT, cipher->BLOCK_SIZE);
+   cipher->encrypt(R);
+
+   xor_buf(V, R, DT, cipher->BLOCK_SIZE);
+   cipher->encrypt(V);
+
+   position = 0;
+   }
+
+/*************************************************
+* Reseed the internal state                      *
+*************************************************/
+void ANSI_X931_RNG::reseed()
+   {
+   prng->reseed();
+
+   SecureVector<byte> key(cipher->MAXIMUM_KEYLENGTH);
+   prng->randomize(key, key.size());
+   cipher->set_key(key, key.size());
+
+   if(V.size() != cipher->BLOCK_SIZE)
+      V.create(cipher->BLOCK_SIZE);
+   prng->randomize(V, V.size());
+
+   update_buffer();
+   }
+
+/*************************************************
+* Add a entropy source to the underlying PRNG    *
+*************************************************/
+void ANSI_X931_RNG::add_entropy_source(EntropySource* src)
+   {
+   prng->add_entropy_source(src);
+   }
+
+/*************************************************
+* Add some entropy to the underlying PRNG        *
+*************************************************/
+void ANSI_X931_RNG::add_entropy(const byte input[], u32bit length)
+   {
+   prng->add_entropy(input, length);
+   }
+
+/*************************************************
+* Check if the the PRNG is seeded                *
+*************************************************/
+bool ANSI_X931_RNG::is_seeded() const
+   {
+   return V.has_items();
+   }
+
+/*************************************************
+* Clear memory of sensitive data                 *
+*************************************************/
+void ANSI_X931_RNG::clear() throw()
+   {
+   cipher->clear();
+   prng->clear();
+   R.clear();
+   V.destroy();
+
+   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(!prng_ptr)
+      throw Invalid_Argument("ANSI_X931_RNG constructor: NULL prng");
+
+   prng = prng_ptr;
+   cipher = get_block_cipher(cipher_name);
+
+   R.create(cipher->BLOCK_SIZE);
+   position = 0;
+   }
+
+/*************************************************
+* ANSI X931 RNG Destructor                       *
+*************************************************/
+ANSI_X931_RNG::~ANSI_X931_RNG()
+   {
+   delete cipher;
+   delete prng;
+   }
+
+}