1 files changed, 59 insertions, 0 deletions
diff --git a/comm/third_party/botan/src/lib/pubkey/rfc6979/rfc6979.cpp b/comm/third_party/botan/src/lib/pubkey/rfc6979/rfc6979.cpp
new file mode 100644
index 0000000000..94b313c3a2
--- /dev/null
+++ b/comm/third_party/botan/src/lib/pubkey/rfc6979/rfc6979.cpp
@@ -0,0 +1,59 @@
+/*
+* RFC 6979 Deterministic Nonce Generator
+* (C) 2014,2015 Jack Lloyd
+*
+* Botan is released under the Simplified BSD License (see license.txt)
+*/
+
+#include <botan/rfc6979.h>
+#include <botan/hmac_drbg.h>
+#include <botan/mac.h>
+
+namespace Botan {
+
+RFC6979_Nonce_Generator::RFC6979_Nonce_Generator(const std::string& hash,
+                                                 const BigInt& order,
+                                                 const BigInt& x) :
+   m_order(order),
+   m_qlen(m_order.bits()),
+   m_rlen(m_qlen / 8 + (m_qlen % 8 ? 1 : 0)),
+   m_rng_in(m_rlen * 2),
+   m_rng_out(m_rlen)
+   {
+   m_hmac_drbg.reset(new HMAC_DRBG(MessageAuthenticationCode::create("HMAC(" + hash + ")")));
+   BigInt::encode_1363(m_rng_in.data(), m_rlen, x);
+   }
+
+RFC6979_Nonce_Generator::~RFC6979_Nonce_Generator()
+   {
+   // for ~unique_ptr
+   }
+
+const BigInt& RFC6979_Nonce_Generator::nonce_for(const BigInt& m)
+   {
+   BigInt::encode_1363(&m_rng_in[m_rlen], m_rlen, m);
+   m_hmac_drbg->clear();
+   m_hmac_drbg->initialize_with(m_rng_in.data(), m_rng_in.size());
+
+   do
+      {
+      m_hmac_drbg->randomize(m_rng_out.data(), m_rng_out.size());
+      m_k.binary_decode(m_rng_out.data(), m_rng_out.size());
+      m_k >>= (8*m_rlen - m_qlen);
+      }
+   while(m_k == 0 || m_k >= m_order);
+
+   return m_k;
+   }
+
+BigInt generate_rfc6979_nonce(const BigInt& x,
+                              const BigInt& q,
+                              const BigInt& h,
+                              const std::string& hash)
+   {
+   RFC6979_Nonce_Generator gen(hash, q, x);
+   BigInt k = gen.nonce_for(h);
+   return k;
+   }
+
+}