1 files changed, 102 insertions, 0 deletions
diff --git a/comm/third_party/botan/src/lib/pk_pad/emsa_x931/emsa_x931.cpp b/comm/third_party/botan/src/lib/pk_pad/emsa_x931/emsa_x931.cpp
new file mode 100644
index 0000000000..b1f698f86d
--- /dev/null
+++ b/comm/third_party/botan/src/lib/pk_pad/emsa_x931/emsa_x931.cpp
@@ -0,0 +1,102 @@
+/*
+* EMSA_X931
+* (C) 1999-2007 Jack Lloyd
+*
+* Botan is released under the Simplified BSD License (see license.txt)
+*/
+
+#include <botan/emsa_x931.h>
+#include <botan/exceptn.h>
+#include <botan/hash_id.h>
+
+namespace Botan {
+
+namespace {
+
+secure_vector<uint8_t> emsa2_encoding(const secure_vector<uint8_t>& msg,
+                                   size_t output_bits,
+                                   const secure_vector<uint8_t>& empty_hash,
+                                   uint8_t hash_id)
+   {
+   const size_t HASH_SIZE = empty_hash.size();
+
+   size_t output_length = (output_bits + 1) / 8;
+
+   if(msg.size() != HASH_SIZE)
+      throw Encoding_Error("EMSA_X931::encoding_of: Bad input length");
+   if(output_length < HASH_SIZE + 4)
+      throw Encoding_Error("EMSA_X931::encoding_of: Output length is too small");
+
+   const bool empty_input = (msg == empty_hash);
+
+   secure_vector<uint8_t> output(output_length);
+
+   output[0] = (empty_input ? 0x4B : 0x6B);
+   output[output_length - 3 - HASH_SIZE] = 0xBA;
+   set_mem(&output[1], output_length - 4 - HASH_SIZE, 0xBB);
+   buffer_insert(output, output_length - (HASH_SIZE + 2), msg.data(), msg.size());
+   output[output_length-2] = hash_id;
+   output[output_length-1] = 0xCC;
+
+   return output;
+   }
+
+}
+
+std::string EMSA_X931::name() const
+   {
+   return "EMSA2(" + m_hash->name() + ")";
+   }
+
+void EMSA_X931::update(const uint8_t input[], size_t length)
+   {
+   m_hash->update(input, length);
+   }
+
+secure_vector<uint8_t> EMSA_X931::raw_data()
+   {
+   return m_hash->final();
+   }
+
+/*
+* EMSA_X931 Encode Operation
+*/
+secure_vector<uint8_t> EMSA_X931::encoding_of(const secure_vector<uint8_t>& msg,
+                                      size_t output_bits,
+                                      RandomNumberGenerator&)
+   {
+   return emsa2_encoding(msg, output_bits, m_empty_hash, m_hash_id);
+   }
+
+/*
+* EMSA_X931 Verify Operation
+*/
+bool EMSA_X931::verify(const secure_vector<uint8_t>& coded,
+                   const secure_vector<uint8_t>& raw,
+                   size_t key_bits)
+   {
+   try
+      {
+      return (coded == emsa2_encoding(raw, key_bits,
+                                      m_empty_hash, m_hash_id));
+      }
+   catch(...)
+      {
+      return false;
+      }
+   }
+
+/*
+* EMSA_X931 Constructor
+*/
+EMSA_X931::EMSA_X931(HashFunction* hash) : m_hash(hash)
+   {
+   m_empty_hash = m_hash->final();
+
+   m_hash_id = ieee1363_hash_id(hash->name());
+
+   if(!m_hash_id)
+      throw Encoding_Error("EMSA_X931 no hash identifier for " + hash->name());
+   }
+
+}